refactor: 重构异步任务系统和计费服务架构

- 重构任务系统：新增 lifecycle (TaskStatus/BillingStatus)、context、application 模块
- 将 video tasks 泛化为 async tasks，支持更通用的异步任务管理
- 新增 Gemini Files 管理模块和管理界面
- 重构 billing 服务：拆分 schema.py 和 service.py
- 新增 candidate 服务模块用于请求候选管理
- 数据库迁移：添加 billing_status、request_id、gemini_file_mappings 表和索引
- 移除废弃的 video_telemetry、task orchestrator 等模块

src/services/auth/oauth/service.py

@@ -804,8 +804,33 @@ class OAuthService:
 
         cfg = OAuthService._get_provider_config(db, provider_type)
 
+        # Read all required fields first, then release DB connection before any awaits.
+        # This prevents holding a pooled connection while doing network I/O.
         auth_url = provider.get_effective_authorization_url(cfg)
         token_url = provider.get_effective_token_url(cfg)
+        redirect_uri = cfg.redirect_uri
+        client_id = cfg.client_id
+        has_secret = bool(cfg.client_secret_encrypted)
+        client_secret = cfg.get_client_secret() if has_secret else None
+
+        # Release DB connection (safe only when session has no pending changes).
+        try:
+            has_pending_changes = bool(db.new) or bool(db.dirty) or bool(db.deleted)
+        except Exception:
+            has_pending_changes = False
+        if not has_pending_changes:
+            original_expire_on_commit = getattr(db, "expire_on_commit", True)
+            db.expire_on_commit = False
+            try:
+                if db.in_transaction():
+                    db.commit()
+            except Exception:
+                try:
+                    db.rollback()
+                except Exception:
+                    pass
+            finally:
+                db.expire_on_commit = original_expire_on_commit
 
         async def _reachable(url: str) -> bool:
             try:
@@ -823,7 +848,7 @@ class OAuthService:
         secret_status = "unknown"
         details = ""
 
-        if cfg.client_secret_encrypted:
+        if has_secret and client_secret:
             # 使用无效 code 做一次 token 请求（仅做粗略判定）
             try:
                 async with httpx.AsyncClient(
@@ -834,9 +859,9 @@ class OAuthService:
                         data={
                             "grant_type": "authorization_code",
                             "code": "invalid",
-                            "redirect_uri": cfg.redirect_uri,
-                            "client_id": cfg.client_id,
-                            "client_secret": cfg.get_client_secret(),
+                            "redirect_uri": redirect_uri,
+                            "client_id": client_id,
+                            "client_secret": client_secret,
                         },
                     )
                 try:

src/services/billing/__init__.py

@@ -29,6 +29,8 @@ from src.services.billing.models import (
     CostBreakdown,
     StandardizedUsage,
 )
+from src.services.billing.schema import BillingSnapshot, CostResult
+from src.services.billing.service import BillingService
 from src.services.billing.templates import BILLING_TEMPLATE_REGISTRY, BillingTemplates
 from src.services.billing.usage_mapper import UsageMapper, map_usage, map_usage_from_response
 
@@ -44,6 +46,10 @@ __all__ = [
     # 计算器
     "BillingCalculator",
     "calculate_request_cost",
+    # 统一入口（Phase2）
+    "BillingService",
+    "BillingSnapshot",
+    "CostResult",
     # 映射器
     "UsageMapper",
     "map_usage",

src/services/billing/schema.py

@@ -0,0 +1,64 @@
+"""
+Billing schema (stable contracts)
+
+These dataclasses are meant to be stored in `Usage.request_metadata` / `Task.request_metadata`
+for auditability. They are internal-only and MUST NOT be exposed to end users without sanitizing.
+"""
+
+from __future__ import annotations
+
+from dataclasses import dataclass, field
+from typing import Any, Literal
+
+BILLING_SNAPSHOT_SCHEMA_VERSION = "1.0"
+
+BillingSnapshotStatus = Literal["complete", "incomplete", "no_rule", "legacy"]
+
+
+@dataclass(frozen=True)
+class BillingSnapshot:
+    """Stable billing snapshot for audit."""
+
+    schema_version: str = BILLING_SNAPSHOT_SCHEMA_VERSION
+
+    # Rule info (optional for legacy/no_rule)
+    rule_id: str | None = None
+    rule_name: str | None = None
+    scope: str | None = None
+
+    # Rule expression (internal, do not expose to clients)
+    expression: str | None = None
+
+    # Dimensions
+    dimensions_used: dict[str, Any] = field(default_factory=dict)
+    missing_required: list[str] = field(default_factory=list)
+
+    # Result
+    cost: float = 0.0
+    status: BillingSnapshotStatus = "no_rule"
+
+    # Audit
+    calculated_at: str = ""  # ISO 8601
+
+    def to_dict(self) -> dict[str, Any]:
+        return {
+            "schema_version": self.schema_version,
+            "rule_id": self.rule_id,
+            "rule_name": self.rule_name,
+            "scope": self.scope,
+            "expression": self.expression,
+            "dimensions_used": self.dimensions_used,
+            "missing_required": self.missing_required,
+            "cost": self.cost,
+            "status": self.status,
+            "calculated_at": self.calculated_at,
+        }
+
+
+@dataclass(frozen=True)
+class CostResult:
+    """Billing calculation output."""
+
+    cost: float
+    status: BillingSnapshotStatus
+    snapshot: BillingSnapshot

src/services/billing/service.py

@@ -0,0 +1,145 @@
+from __future__ import annotations
+
+from datetime import datetime, timezone
+from typing import Any
+
+from sqlalchemy.orm import Session
+
+from src.config.settings import config
+from src.core.logger import logger
+from src.services.billing.dimension_collector_service import DimensionCollectorService
+from src.services.billing.formula_engine import BillingIncompleteError, FormulaEngine
+from src.services.billing.rule_service import BillingRuleService
+from src.services.model.cost import ModelCostService
+
+from .schema import BILLING_SNAPSHOT_SCHEMA_VERSION, BillingSnapshot, CostResult
+
+
+class BillingService:
+    """
+    BillingService (pure-ish application helper for billing domain).
+
+    Notes:
+    - This service **does not** write Usage rows.
+    - It may read billing rules & collectors from DB.
+    """
+
+    def __init__(self, db: Session):
+        self.db = db
+        self._formula_engine = FormulaEngine()
+        self._dimension_collector = DimensionCollectorService(db)
+
+    def collect_dimensions(
+        self,
+        *,
+        api_format: str | None,
+        task_type: str | None,
+        request: dict[str, Any] | None = None,
+        response: dict[str, Any] | None = None,
+        metadata: dict[str, Any] | None = None,
+        base_dimensions: dict[str, Any] | None = None,
+    ) -> dict[str, Any]:
+        return self._dimension_collector.collect_dimensions(
+            api_format=api_format,
+            task_type=task_type,
+            request=request,
+            response=response,
+            metadata=metadata,
+            base_dimensions=base_dimensions,
+        )
+
+    def calculate(
+        self,
+        *,
+        task_type: str,
+        model: str,
+        provider_id: str,
+        dimensions: dict[str, Any],
+        strict_mode: bool | None = None,
+    ) -> CostResult:
+        """
+        Calculate cost for a task.
+
+        Returns:
+            CostResult (includes BillingSnapshot)
+
+        Raises:
+            BillingIncompleteError: when strict_mode=True and required dims missing.
+        """
+        strict = config.billing_strict_mode if strict_mode is None else bool(strict_mode)
+
+        lookup = BillingRuleService.find_rule(
+            self.db,
+            provider_id=provider_id,
+            model_name=model,
+            task_type=task_type,
+        )
+
+        if lookup and lookup.rule and lookup.rule.expression:
+            rule = lookup.rule
+            result = self._formula_engine.evaluate(
+                expression=rule.expression,
+                variables=rule.variables or {},
+                dimensions=dimensions,
+                dimension_mappings=rule.dimension_mappings or {},
+                strict_mode=strict,
+            )
+            cost = float(result.cost) if result.status == "complete" else 0.0
+            snapshot = BillingSnapshot(
+                schema_version=BILLING_SNAPSHOT_SCHEMA_VERSION,
+                rule_id=str(rule.id),
+                rule_name=str(rule.name),
+                scope=str(getattr(lookup, "scope", None) or ""),
+                expression=str(rule.expression),
+                dimensions_used=dimensions,
+                missing_required=result.missing_required,
+                cost=cost,
+                status=result.status,
+                calculated_at=datetime.now(timezone.utc).isoformat(),
+            )
+            return CostResult(cost=cost, status=result.status, snapshot=snapshot)
+
+        # No rule fallback
+        if task_type in ("chat", "cli"):
+            input_tokens = int(dimensions.get("input_tokens") or 0)
+            output_tokens = int(dimensions.get("output_tokens") or 0)
+            cost = float(
+                ModelCostService.calculate_cost(
+                    model=model,
+                    input_tokens=input_tokens,
+                    output_tokens=output_tokens,
+                )
+            )
+            snapshot = BillingSnapshot(
+                schema_version=BILLING_SNAPSHOT_SCHEMA_VERSION,
+                rule_id=None,
+                rule_name=None,
+                scope=None,
+                expression=None,
+                dimensions_used=dimensions,
+                missing_required=[],
+                cost=cost,
+                status="legacy",
+                calculated_at=datetime.now(timezone.utc).isoformat(),
+            )
+            return CostResult(cost=cost, status="legacy", snapshot=snapshot)
+
+        logger.warning(
+            "No billing rule for task (task_type=%s, model=%s, provider_id=%s)",
+            task_type,
+            model,
+            provider_id,
+        )
+        snapshot = BillingSnapshot(
+            schema_version=BILLING_SNAPSHOT_SCHEMA_VERSION,
+            rule_id=None,
+            rule_name=None,
+            scope=None,
+            expression=None,
+            dimensions_used=dimensions,
+            missing_required=[],
+            cost=0.0,
+            status="no_rule",
+            calculated_at=datetime.now(timezone.utc).isoformat(),
+        )
+        return CostResult(cost=0.0, status="no_rule", snapshot=snapshot)

src/services/cache/aware_scheduler.py

@@ -182,6 +182,43 @@ class CacheAwareScheduler:
             "last_reservation_result": None,
         }
 
+    @staticmethod
+    def _release_db_connection_before_await(db: Session) -> None:
+        """
+        Best-effort: end a read-only transaction before awaiting async I/O.
+
+        This scheduler does a lot of async work (cache/Redis) mixed with sync SQLAlchemy reads.
+        If a SELECT has already started a transaction, the pooled connection can remain checked
+        out while we await, causing pool pressure under concurrency.
+
+        Safety:
+        - Only commits when the Session has no ORM pending changes.
+        - Temporarily disables expire_on_commit to keep already-loaded ORM objects usable.
+        """
+        try:
+            if db is None:
+                return
+            has_pending_changes = bool(db.new) or bool(db.dirty) or bool(db.deleted)
+            if has_pending_changes:
+                return
+            if not db.in_transaction():
+                return
+
+            original_expire_on_commit = getattr(db, "expire_on_commit", True)
+            db.expire_on_commit = False
+            try:
+                db.commit()
+            except Exception:
+                try:
+                    db.rollback()
+                except Exception:
+                    pass
+            finally:
+                db.expire_on_commit = original_expire_on_commit
+        except Exception:
+            # Never let this optimization break scheduling
+            return
+
     async def _ensure_initialized(self) -> None:
         """确保所有异步组件已初始化"""
         if self._affinity_manager is None:
@@ -577,6 +614,8 @@ class CacheAwareScheduler:
         Returns:
             (候选列表, global_model_id) - global_model_id 用于缓存亲和性
         """
+        # If the caller already touched the DB, release the connection before we do async work.
+        self._release_db_connection_before_await(db)
         await self._ensure_initialized()
 
         target_format = normalize_endpoint_signature(api_format)
@@ -648,6 +687,9 @@ class CacheAwareScheduler:
             provider_limit=provider_limit,
         )
 
+        # Provider query starts a transaction; release connection before entering async candidate build.
+        self._release_db_connection_before_await(db)
+
         logger.debug(
             "[Scheduler] Found %d active providers",
             len(providers),
@@ -680,8 +722,13 @@ class CacheAwareScheduler:
 
         # 2. 构建候选列表（传入 is_stream 和 capability_requirements 用于过滤）
         from src.config.settings import config
+        from src.services.system.config import SystemConfigService
 
-        global_conversion_enabled = config.format_conversion_enabled
+        # 全局格式转换开关：优先使用数据库配置，回退到环境变量
+        global_conversion_enabled = SystemConfigService.is_format_conversion_enabled(db)
+        # 如果环境变量明确禁用，则禁用（环境变量可作为强制禁用开关）
+        if not config.format_conversion_enabled:
+            global_conversion_enabled = False
         candidates = await self._build_candidates(
             db=db,
             providers=providers,
@@ -801,6 +848,9 @@ class CacheAwareScheduler:
             - supported_capabilities: 模型支持的能力列表
             - provider_model_names: Provider 侧可用的模型名称集合（主名称 + 映射名称，按 api_format 过滤）
         """
+        # Avoid holding a DB connection while awaiting cache/Redis inside ModelCacheService.
+        self._release_db_connection_before_await(db)
+
         # 使用 ModelCacheService 解析模型名称（支持映射名）
         global_model = await ModelCacheService.resolve_global_model_by_name_or_mapping(
             db, model_name
@@ -1120,18 +1170,34 @@ class CacheAwareScheduler:
                     str(getattr(endpoint, "endpoint_kind", "")).strip().lower(),
                 )
 
+                # 计算格式转换的有效开关状态（三层优先级）
+                # 全局 ON → 强制允许（跳过端点检查）
+                # 全局 OFF → 提供商 ON → 强制允许（跳过端点检查）
+                # 全局 OFF → 提供商 OFF → 看端点配置
+                provider_allows_conversion = getattr(provider, "enable_format_conversion", True)
+                effective_conversion_enabled = (
+                    global_conversion_enabled or provider_allows_conversion
+                )
+                # 如果全局或提供商开关为 ON，跳过端点配置检查
+                skip_endpoint_check = global_conversion_enabled or provider_allows_conversion
+
                 is_compatible, needs_conversion, _compat_reason = is_format_compatible(
                     client_format_str,
                     endpoint_format_str,
                     getattr(endpoint, "format_acceptance_config", None),
                     is_stream,
-                    global_conversion_enabled,
+                    effective_conversion_enabled,
+                    skip_endpoint_check=skip_endpoint_check,
                 )
                 logger.debug(
-                    "[Scheduler] Format compatibility: client=%s, endpoint=%s, compatible=%s, reason=%s",
+                    "[Scheduler] Format compatibility: client=%s, endpoint=%s, compatible=%s, "
+                    "global=%s, provider=%s, skip_endpoint=%s, reason=%s",
                     client_format_str,
                     endpoint_format_str,
                     is_compatible,
+                    global_conversion_enabled,
+                    provider_allows_conversion,
+                    skip_endpoint_check,
                     _compat_reason,
                 )
                 if not is_compatible:

src/services/candidate/__init__.py

@@ -0,0 +1,28 @@
+"""
+Candidate domain (Phase2)
+
+This package centralizes:
+- candidate resolving (Provider/Endpoint/Key combinations)
+- request_candidates recording & audit
+- failover execution policies
+"""
+
+from src.services.candidate.policy import RetryMode, RetryPolicy, SkipPolicy
+from src.services.candidate.schema import (
+    CANDIDATE_KEY_SCHEMA_VERSION,
+    CandidateKey,
+    CandidateResult,
+)
+from src.services.candidate.service import CandidateService
+
+__all__ = [
+    "CandidateService",
+    # schema
+    "CANDIDATE_KEY_SCHEMA_VERSION",
+    "CandidateKey",
+    "CandidateResult",
+    # policies
+    "RetryMode",
+    "RetryPolicy",
+    "SkipPolicy",
+]

src/services/candidate/failover.py

@@ -0,0 +1,57 @@
+from __future__ import annotations
+
+from typing import Any, Protocol
+
+from sqlalchemy.orm import Session
+
+from src.services.cache.aware_scheduler import ProviderCandidate
+
+from .policy import RetryPolicy, SkipPolicy
+from .schema import CandidateKey, CandidateResult
+
+
+class AttemptFunc(Protocol):
+    async def __call__(self, candidate: ProviderCandidate) -> Any: ...
+
+
+class FailoverEngine:
+    """
+    FailoverEngine executes candidate attempts under policies.
+
+    Phase2 scaffolding: implementation will gradually replace legacy orchestrators.
+    """
+
+    def __init__(self, db: Session):
+        self.db = db
+
+    async def execute(
+        self,
+        *,
+        candidates: list[ProviderCandidate],
+        attempt_func: AttemptFunc,
+        retry_policy: RetryPolicy,
+        skip_policy: SkipPolicy,
+        request_id: str | None = None,
+        max_candidates: int | None = None,
+    ) -> CandidateResult:
+        # NOTE: intentionally minimal for now; legacy orchestrators still in use.
+        # This will be implemented when migrating video/chat flows to CandidateService.
+        _ = (retry_policy, skip_policy, request_id, max_candidates)
+        candidate_keys: list[CandidateKey] = []
+        for idx, cand in enumerate(candidates):
+            candidate_keys.append(
+                CandidateKey(
+                    candidate_index=idx,
+                    provider_id=str(cand.provider.id),
+                    provider_name=str(cand.provider.name),
+                    endpoint_id=str(cand.endpoint.id),
+                    key_id=str(cand.key.id),
+                    key_name=str(getattr(cand.key, "name", "") or ""),
+                    auth_type=str(getattr(cand.key, "auth_type", "") or ""),
+                    priority=int(getattr(cand.key, "priority", 0) or 0),
+                    is_cached=bool(getattr(cand, "is_cached", False)),
+                    status="available",
+                )
+            )
+
+        raise NotImplementedError("FailoverEngine.execute is not implemented yet")

src/services/candidate/policy.py

@@ -0,0 +1,41 @@
+from __future__ import annotations
+
+from dataclasses import dataclass
+from enum import Enum
+
+
+class RetryMode(str, Enum):
+    """Retry mode for candidate attempts."""
+
+    PRE_EXPAND = "pre_expand"  # pre-create retry slots (sync)
+    ON_DEMAND = "on_demand"  # create retry record only when retry happens
+    DISABLED = "disabled"  # no retry
+
+
+@dataclass(frozen=True)
+class RetryPolicy:
+    """Unified retry policy."""
+
+    mode: RetryMode = RetryMode.DISABLED
+    max_retries: int = 1
+    retry_on_cached_only: bool = True
+
+    @classmethod
+    def for_sync_task(cls) -> "RetryPolicy":
+        return cls(mode=RetryMode.PRE_EXPAND, max_retries=2)
+
+    @classmethod
+    def for_async_task(cls) -> "RetryPolicy":
+        return cls(mode=RetryMode.DISABLED, max_retries=1)
+
+    @classmethod
+    def for_async_submit_with_retry(cls) -> "RetryPolicy":
+        return cls(mode=RetryMode.ON_DEMAND, max_retries=2)
+
+
+@dataclass(frozen=True)
+class SkipPolicy:
+    """Rules for skipping unsupported candidates."""
+
+    allow_format_conversion: bool = True
+    supported_auth_types: set[str] | None = None

src/services/candidate/recorder.py

@@ -0,0 +1,59 @@
+from __future__ import annotations
+
+from sqlalchemy.orm import Session
+
+from src.models.database import RequestCandidate
+
+from .schema import CandidateKey
+
+
+class CandidateRecorder:
+    """Read helpers for RequestCandidate audit data."""
+
+    def __init__(self, db: Session):
+        self.db = db
+
+    def get_candidate_keys(self, request_id: str) -> list[CandidateKey]:
+        rows: list[RequestCandidate] = (
+            self.db.query(RequestCandidate)
+            .filter(RequestCandidate.request_id == request_id)
+            .order_by(RequestCandidate.candidate_index.asc(), RequestCandidate.retry_index.asc())
+            .all()
+        )
+
+        result: list[CandidateKey] = []
+        for row in rows:
+            provider_name = None
+            if getattr(row, "provider", None) is not None:
+                provider_name = getattr(row.provider, "name", None)
+
+            key_name = None
+            auth_type = None
+            priority = None
+            if getattr(row, "key", None) is not None:
+                key_name = getattr(row.key, "name", None)
+                auth_type = getattr(row.key, "auth_type", None)
+                priority = getattr(row.key, "priority", None)
+
+            result.append(
+                CandidateKey(
+                    candidate_index=int(row.candidate_index or 0),
+                    retry_index=int(row.retry_index or 0),
+                    provider_id=str(row.provider_id) if row.provider_id else None,
+                    provider_name=str(provider_name) if provider_name else None,
+                    endpoint_id=str(row.endpoint_id) if row.endpoint_id else None,
+                    key_id=str(row.key_id) if row.key_id else None,
+                    key_name=str(key_name) if key_name else None,
+                    auth_type=str(auth_type) if auth_type else None,
+                    priority=int(priority) if priority is not None else None,
+                    is_cached=bool(getattr(row, "is_cached", False)),
+                    status=str(getattr(row, "status", "") or "pending"),
+                    skip_reason=getattr(row, "skip_reason", None),
+                    error_type=getattr(row, "error_type", None),
+                    error_message=getattr(row, "error_message", None),
+                    status_code=getattr(row, "status_code", None),
+                    latency_ms=getattr(row, "latency_ms", None),
+                )
+            )
+
+        return result

src/services/candidate/resolver.py

@@ -0,0 +1,10 @@
+"""
+CandidateResolver facade import.
+
+Phase2 keeps the implementation in `services/orchestration/` for compatibility,
+and gradually migrates it into this package.
+"""
+
+from src.services.orchestration.candidate_resolver import CandidateResolver
+
+__all__ = ["CandidateResolver"]

src/services/candidate/schema.py

@@ -0,0 +1,71 @@
+from __future__ import annotations
+
+from dataclasses import dataclass
+from typing import Any
+
+from src.services.cache.aware_scheduler import ProviderCandidate
+
+CANDIDATE_KEY_SCHEMA_VERSION = "1.0"
+
+
+@dataclass(frozen=True)
+class CandidateKey:
+    """Stable candidate key snapshot for audit."""
+
+    schema_version: str = CANDIDATE_KEY_SCHEMA_VERSION
+
+    candidate_index: int = 0
+    retry_index: int = 0
+
+    provider_id: str | None = None
+    provider_name: str | None = None
+    endpoint_id: str | None = None
+    key_id: str | None = None
+    key_name: str | None = None
+    auth_type: str | None = None
+    priority: int | None = None
+    is_cached: bool = False
+
+    status: str = "pending"  # pending/success/failed/skipped/available/...
+    skip_reason: str | None = None
+    error_type: str | None = None
+    error_message: str | None = None
+    status_code: int | None = None
+    latency_ms: int | None = None
+
+    def to_dict(self) -> dict[str, Any]:
+        data: dict[str, Any] = {
+            "schema_version": self.schema_version,
+            "candidate_index": self.candidate_index,
+            "retry_index": self.retry_index,
+            "provider_id": self.provider_id,
+            "provider_name": self.provider_name,
+            "endpoint_id": self.endpoint_id,
+            "key_id": self.key_id,
+            "key_name": self.key_name,
+            "auth_type": self.auth_type,
+            "priority": self.priority,
+            "is_cached": self.is_cached,
+            "status": self.status,
+            "skip_reason": self.skip_reason,
+            "error_type": self.error_type,
+            "error_message": self.error_message,
+            "status_code": self.status_code,
+            "latency_ms": self.latency_ms,
+        }
+        # drop Nones for compact audit payload
+        return {k: v for k, v in data.items() if v is not None}
+
+
+@dataclass(slots=True)
+class CandidateResult:
+    """Failover execution result."""
+
+    success: bool
+    selected: ProviderCandidate | None
+    selected_index: int | None
+    candidate_keys: list[CandidateKey]
+
+    external_task_id: str | None = None
+    error: Exception | None = None
+    last_status_code: int | None = None

src/services/candidate/service.py

@@ -0,0 +1,515 @@
+from __future__ import annotations
+
+import re
+from datetime import datetime, timezone
+from typing import Any
+
+import httpx
+from sqlalchemy import update
+from sqlalchemy.orm import Session
+
+from src.config.settings import config
+from src.core.exceptions import ProviderNotAvailableException
+from src.core.logger import logger
+from src.models.database import ApiKey, RequestCandidate
+from src.services.billing.rule_service import BillingRuleLookupResult, BillingRuleService
+from src.services.cache.aware_scheduler import ProviderCandidate, get_cache_aware_scheduler
+from src.services.candidate.submit import (
+    AllCandidatesFailedError,
+    SubmitOutcome,
+    UpstreamClientRequestError,
+)
+from src.services.orchestration.error_classifier import ErrorClassifier
+from src.services.system.config import SystemConfigService
+
+from .recorder import CandidateRecorder
+from .resolver import CandidateResolver
+from .schema import CandidateKey
+
+_SENSITIVE_PATTERN = re.compile(
+    r"(api[_-]?key|token|bearer|authorization)[=:\s]+\S+",
+    re.IGNORECASE,
+)
+
+
+def _sanitize(message: str, max_length: int = 200) -> str:
+    if not message:
+        return "request_failed"
+    return _SENSITIVE_PATTERN.sub("[REDACTED]", message)[:max_length]
+
+
+class CandidateService:
+    """
+    CandidateService (Facade).
+
+    Phase2 note: this is introduced as a new domain entrypoint. Legacy orchestrators
+    still exist and will be migrated gradually to use this service.
+    """
+
+    def __init__(self, db: Session, redis_client: Any | None = None) -> None:
+        self.db = db
+        self.redis = redis_client
+        self._cache_scheduler = None
+        self._resolver: CandidateResolver | None = None
+        self._error_classifier: ErrorClassifier | None = None
+        self._recorder = CandidateRecorder(db)
+
+    async def _ensure_initialized(self) -> None:
+        if self._cache_scheduler is not None:
+            return
+
+        priority_mode = SystemConfigService.get_config(
+            self.db,
+            "provider_priority_mode",
+            "provider",
+        )
+        scheduling_mode = SystemConfigService.get_config(
+            self.db,
+            "scheduling_mode",
+            "cache_affinity",
+        )
+        self._cache_scheduler = await get_cache_aware_scheduler(
+            self.redis,
+            priority_mode=priority_mode,
+            scheduling_mode=scheduling_mode,
+        )
+        self._resolver = CandidateResolver(db=self.db, cache_scheduler=self._cache_scheduler)
+        self._error_classifier = ErrorClassifier(db=self.db, cache_scheduler=self._cache_scheduler)
+
+    async def resolve(
+        self,
+        *,
+        api_format: str,
+        model_name: str,
+        affinity_key: str,
+        user_api_key: ApiKey | None = None,
+        request_id: str | None = None,
+        is_stream: bool = False,
+        capability_requirements: dict[str, bool] | None = None,
+        preferred_key_ids: list[str] | None = None,
+    ) -> tuple[list[ProviderCandidate], str]:
+        await self._ensure_initialized()
+        assert self._resolver is not None
+        return await self._resolver.fetch_candidates(
+            api_format=api_format,
+            model_name=model_name,
+            affinity_key=affinity_key,
+            user_api_key=user_api_key,
+            request_id=request_id,
+            is_stream=is_stream,
+            capability_requirements=capability_requirements,
+            preferred_key_ids=preferred_key_ids,
+        )
+
+    def _should_stop_on_http_error(self, *, status_code: int, error_text: str) -> bool:
+        """
+        Decide whether an upstream HTTP error is a client error (no failover).
+
+        Rules:
+        - 401/403/429 are usually key/permission/ratelimit issues -> allow failover
+        - other 4xx: stop only if ErrorClassifier says it's a client error
+        """
+        if status_code in (401, 403, 429):
+            return False
+        if 400 <= status_code < 500:
+            assert self._error_classifier is not None
+            return self._error_classifier.is_client_error(error_text)
+        return False
+
+    async def submit_with_failover(
+        self,
+        *,
+        api_format: str,
+        model_name: str,
+        affinity_key: str,
+        user_api_key: ApiKey,
+        request_id: str | None,
+        task_type: str,
+        submit_func: Any,
+        extract_external_task_id: Any,
+        supported_auth_types: set[str] | None = None,
+        allow_format_conversion: bool = False,
+        capability_requirements: dict[str, bool] | None = None,
+        max_candidates: int | None = None,
+    ) -> SubmitOutcome:
+        """
+        Submit async task with failover, returning the selected candidate + external_task_id.
+
+        Phase2 submit entrypoint (replaces legacy submit orchestrator).
+        """
+        # IMPORTANT:
+        # This method awaits upstream HTTP calls. If we have an open DB transaction before awaiting,
+        # the connection can be held for a long time (pool exhaustion under concurrency).
+        #
+        # Also note SQLAlchemy's default expire_on_commit=True would expire ORM objects and may
+        # trigger unexpected lazy DB loads after we commit (potentially during the await).
+        # We disable it temporarily to keep candidate/provider/key objects in-memory.
+        original_expire_on_commit = getattr(self.db, "expire_on_commit", True)
+        self.db.expire_on_commit = False
+        await self._ensure_initialized()
+        assert self._resolver is not None
+        try:
+            candidates, _global_model_id = await self._resolver.fetch_candidates(
+                api_format=api_format,
+                model_name=model_name,
+                affinity_key=affinity_key,
+                user_api_key=user_api_key,
+                request_id=request_id,
+                is_stream=False,
+                capability_requirements=capability_requirements,
+            )
+
+            if not candidates:
+                raise ProviderNotAvailableException("No candidates available")
+
+            if max_candidates is not None and max_candidates > 0:
+                candidates = candidates[:max_candidates]
+
+            # Pre-create RequestCandidate records (no retry expand for async submit stage)
+            record_map: dict[tuple[int, int], str] = {}
+            if request_id:
+                try:
+                    record_map = self.create_candidate_records(
+                        candidates=candidates,
+                        request_id=request_id,
+                        user_api_key=user_api_key,
+                        required_capabilities=capability_requirements,
+                        expand_retries=False,
+                    )
+                except Exception as exc:
+                    logger.warning(
+                        "[CandidateService] Failed to create candidate records: %s",
+                        _sanitize(str(exc)),
+                    )
+                    record_map = {}
+
+            candidate_keys: list[dict[str, Any]] = []
+            eligible_count = 0
+            last_status_code: int | None = None
+
+            for idx, cand in enumerate(candidates):
+                now = datetime.now(timezone.utc)
+                auth_type = getattr(cand.key, "auth_type", "api_key") or "api_key"
+
+                candidate_info: dict[str, Any] = {
+                    "index": idx,
+                    "provider_id": cand.provider.id,
+                    "provider_name": cand.provider.name,
+                    "endpoint_id": cand.endpoint.id,
+                    "key_id": cand.key.id,
+                    "key_name": getattr(cand.key, "name", None),
+                    "auth_type": auth_type,
+                    "priority": getattr(cand.key, "priority", 0) or 0,
+                    "is_cached": bool(getattr(cand, "is_cached", False)),
+                }
+                candidate_keys.append(candidate_info)
+
+                record_id = record_map.get((idx, 0))
+
+                # Scheduler marked skip
+                if getattr(cand, "is_skipped", False):
+                    skip_reason = getattr(cand, "skip_reason", None) or "skipped"
+                    candidate_info.update({"skipped": True, "skip_reason": skip_reason})
+                    if record_id:
+                        # record is usually already skipped, but keep it consistent
+                        self.db.execute(
+                            update(RequestCandidate)
+                            .where(RequestCandidate.id == record_id)
+                            .values(status="skipped", skip_reason=skip_reason)
+                        )
+                    continue
+
+                # Format conversion checks
+                # 优先级：全局开关 ON 强制允许，全局开关 OFF 看提供商开关
+                needs_conversion = bool(getattr(cand, "needs_conversion", False))
+                if needs_conversion:
+                    # 1. Check handler-level switch (handler 不支持则直接跳过)
+                    if not allow_format_conversion:
+                        skip_reason = "format_conversion_not_supported"
+                        candidate_info.update({"skipped": True, "skip_reason": skip_reason})
+                        if record_id:
+                            self.db.execute(
+                                update(RequestCandidate)
+                                .where(RequestCandidate.id == record_id)
+                                .values(status="skipped", skip_reason=skip_reason)
+                            )
+                        continue
+
+                    # 2. Check global + provider switches
+                    # 全局 ON → 允许；全局 OFF → 看提供商
+                    from src.services.system.config import SystemConfigService
+
+                    global_enabled = SystemConfigService.is_format_conversion_enabled(self.db)
+                    provider_enabled = getattr(cand.provider, "enable_format_conversion", True)
+                    effective_enabled = global_enabled or provider_enabled
+
+                    if not effective_enabled:
+                        skip_reason = "format_conversion_disabled"
+                        candidate_info.update(
+                            {
+                                "skipped": True,
+                                "skip_reason": skip_reason,
+                                "global_conversion_enabled": global_enabled,
+                                "provider_conversion_enabled": provider_enabled,
+                            }
+                        )
+                        if record_id:
+                            self.db.execute(
+                                update(RequestCandidate)
+                                .where(RequestCandidate.id == record_id)
+                                .values(status="skipped", skip_reason=skip_reason)
+                            )
+                        continue
+
+                # auth_type filter
+                if supported_auth_types is not None and auth_type not in supported_auth_types:
+                    skip_reason = f"unsupported_auth_type:{auth_type}"
+                    candidate_info.update({"skipped": True, "skip_reason": skip_reason})
+                    if record_id:
+                        self.db.execute(
+                            update(RequestCandidate)
+                            .where(RequestCandidate.id == record_id)
+                            .values(status="skipped", skip_reason=skip_reason)
+                        )
+                    continue
+
+                # billing rule filter
+                rule_lookup: BillingRuleLookupResult | None = None
+                has_billing_rule = True
+                if config.billing_require_rule:
+                    rule_lookup = BillingRuleService.find_rule(
+                        self.db,
+                        provider_id=cand.provider.id,
+                        model_name=model_name,
+                        task_type=task_type,
+                    )
+                    has_billing_rule = rule_lookup is not None
+                    if not has_billing_rule:
+                        skip_reason = "billing_rule_missing"
+                        candidate_info.update(
+                            {"has_billing_rule": False, "skipped": True, "skip_reason": skip_reason}
+                        )
+                        if record_id:
+                            self.db.execute(
+                                update(RequestCandidate)
+                                .where(RequestCandidate.id == record_id)
+                                .values(status="skipped", skip_reason=skip_reason)
+                            )
+                        continue
+                candidate_info["has_billing_rule"] = has_billing_rule
+
+                eligible_count += 1
+
+                # Mark pending
+                if record_id:
+                    self.db.execute(
+                        update(RequestCandidate)
+                        .where(RequestCandidate.id == record_id)
+                        .values(status="pending", started_at=now)
+                    )
+
+                # Flush/commit BEFORE awaiting upstream submit to avoid holding DB connections
+                # during potentially slow network operations.
+                if self.db.in_transaction():
+                    try:
+                        self.db.commit()
+                    except Exception:
+                        self.db.rollback()
+                        raise
+
+                # Attempt submit (upstream HTTP)
+                try:
+                    response: httpx.Response = await submit_func(cand)
+                except Exception as exc:
+                    finished_at = datetime.now(timezone.utc)
+                    error_msg = _sanitize(str(exc))
+                    candidate_info.update(
+                        {
+                            "attempt_status": "exception",
+                            "error_type": type(exc).__name__,
+                            "error_message": error_msg,
+                        }
+                    )
+                    if record_id:
+                        self.db.execute(
+                            update(RequestCandidate)
+                            .where(RequestCandidate.id == record_id)
+                            .values(
+                                status="failed",
+                                error_type=type(exc).__name__,
+                                error_message=error_msg,
+                                finished_at=finished_at,
+                            )
+                        )
+                    continue
+
+                last_status_code = int(getattr(response, "status_code", 0) or 0)
+
+                if response.status_code >= 400:
+                    finished_at = datetime.now(timezone.utc)
+                    try:
+                        error_text = response.text or ""
+                    except Exception:
+                        error_text = ""
+                    error_msg = _sanitize(error_text)
+                    candidate_info.update(
+                        {
+                            "attempt_status": "http_error",
+                            "status_code": response.status_code,
+                            "error_message": error_msg,
+                        }
+                    )
+                    if record_id:
+                        self.db.execute(
+                            update(RequestCandidate)
+                            .where(RequestCandidate.id == record_id)
+                            .values(
+                                status="failed",
+                                status_code=response.status_code,
+                                error_type="http_error",
+                                error_message=error_msg,
+                                finished_at=finished_at,
+                            )
+                        )
+
+                    if self._should_stop_on_http_error(
+                        status_code=response.status_code, error_text=error_text
+                    ):
+                        try:
+                            self.db.commit()
+                        except Exception:
+                            self.db.rollback()
+                        raise UpstreamClientRequestError(
+                            response=response,
+                            candidate_keys=candidate_keys,
+                        )
+                    continue
+
+                # Parse JSON
+                payload: dict[str, Any] | None = None
+                try:
+                    data = response.json()
+                    if isinstance(data, dict):
+                        payload = data
+                except Exception as exc:
+                    finished_at = datetime.now(timezone.utc)
+                    error_msg = _sanitize(str(exc))
+                    candidate_info.update(
+                        {
+                            "attempt_status": "invalid_json",
+                            "error_type": type(exc).__name__,
+                            "error_message": error_msg,
+                        }
+                    )
+                    if record_id:
+                        self.db.execute(
+                            update(RequestCandidate)
+                            .where(RequestCandidate.id == record_id)
+                            .values(
+                                status="failed",
+                                status_code=response.status_code,
+                                error_type="invalid_json",
+                                error_message=error_msg,
+                                finished_at=finished_at,
+                            )
+                        )
+                    continue
+
+                external_task_id = extract_external_task_id(payload or {})
+                if not external_task_id:
+                    finished_at = datetime.now(timezone.utc)
+                    candidate_info.update(
+                        {
+                            "attempt_status": "empty_task_id",
+                            "error_message": "Upstream returned empty task id",
+                        }
+                    )
+                    if record_id:
+                        self.db.execute(
+                            update(RequestCandidate)
+                            .where(RequestCandidate.id == record_id)
+                            .values(
+                                status="failed",
+                                status_code=response.status_code,
+                                error_type="empty_task_id",
+                                error_message="Upstream returned empty task id",
+                                finished_at=finished_at,
+                            )
+                        )
+                    continue
+
+                # Success
+                finished_at = datetime.now(timezone.utc)
+                candidate_info.update({"attempt_status": "success", "selected": True})
+                if record_id:
+                    self.db.execute(
+                        update(RequestCandidate)
+                        .where(RequestCandidate.id == record_id)
+                        .values(
+                            status="success",
+                            status_code=response.status_code,
+                            finished_at=finished_at,
+                        )
+                    )
+                try:
+                    self.db.commit()
+                except Exception:
+                    self.db.rollback()
+
+                return SubmitOutcome(
+                    candidate=cand,
+                    candidate_keys=candidate_keys,
+                    external_task_id=str(external_task_id),
+                    rule_lookup=rule_lookup,
+                    upstream_payload=payload,
+                    upstream_headers=dict(response.headers),
+                    upstream_status_code=response.status_code,
+                )
+
+            # Persist candidate records before raising
+            try:
+                self.db.commit()
+            except Exception:
+                self.db.rollback()
+
+            if eligible_count == 0:
+                reason = "no_eligible_candidates"
+                if config.billing_require_rule:
+                    reason = "no_candidate_with_billing_rule"
+                raise AllCandidatesFailedError(
+                    reason=reason,
+                    candidate_keys=candidate_keys,
+                    last_status_code=last_status_code,
+                )
+
+            raise AllCandidatesFailedError(
+                reason="all_candidates_failed",
+                candidate_keys=candidate_keys,
+                last_status_code=last_status_code,
+            )
+        finally:
+            # Restore Session behavior for the rest of the request lifecycle.
+            self.db.expire_on_commit = original_expire_on_commit
+
+    def create_candidate_records(
+        self,
+        *,
+        candidates: list[ProviderCandidate],
+        request_id: str,
+        user_api_key: ApiKey,
+        required_capabilities: dict[str, bool] | None = None,
+        expand_retries: bool = True,
+    ) -> dict[tuple[int, int], str]:
+        # CandidateResolver.create_candidate_records is currently the canonical implementation
+        assert self._resolver is not None, "Call resolve() once before create_candidate_records()"
+        return self._resolver.create_candidate_records(
+            all_candidates=candidates,
+            request_id=request_id,
+            user_id=str(user_api_key.user_id),
+            user_api_key=user_api_key,
+            required_capabilities=required_capabilities,
+            expand_retries=expand_retries,
+        )
+
+    def get_candidate_keys(self, request_id: str) -> list["CandidateKey"]:
+        return self._recorder.get_candidate_keys(request_id)

src/services/candidate/submit.py

@@ -0,0 +1,66 @@
+from __future__ import annotations
+
+from dataclasses import dataclass
+from typing import Any, Protocol, runtime_checkable
+
+import httpx
+
+from src.services.billing.rule_service import BillingRuleLookupResult
+from src.services.cache.aware_scheduler import ProviderCandidate
+
+
+@runtime_checkable
+class SubmitFunc(Protocol):
+    async def __call__(self, candidate: ProviderCandidate) -> httpx.Response: ...
+
+
+@runtime_checkable
+class ExtractExternalTaskIdFunc(Protocol):
+    def __call__(self, payload: dict[str, Any]) -> str | None: ...
+
+
+class UpstreamClientRequestError(RuntimeError):
+    """可判定为客户端请求问题（不应 failover）的上游错误。"""
+
+    def __init__(
+        self,
+        *,
+        response: httpx.Response,
+        candidate_keys: list[dict[str, Any]],
+    ) -> None:
+        self.response = response
+        self.candidate_keys = candidate_keys
+        super().__init__(f"Upstream client error: HTTP {response.status_code}")
+
+
+class AllCandidatesFailedError(RuntimeError):
+    def __init__(
+        self,
+        *,
+        reason: str,
+        candidate_keys: list[dict[str, Any]],
+        last_status_code: int | None = None,
+    ) -> None:
+        self.reason = reason
+        self.candidate_keys = candidate_keys
+        self.last_status_code = last_status_code
+        super().__init__(f"All candidates failed: {reason}")
+
+
+class CandidateUnsupportedError(RuntimeError):
+    """候选不被当前任务支持（如 auth_type/格式转换需求不支持）。"""
+
+
+class CandidateSubmissionError(RuntimeError):
+    """候选提交异常（网络/解密/解析等）。"""
+
+
+@dataclass(slots=True)
+class SubmitOutcome:
+    candidate: ProviderCandidate
+    candidate_keys: list[dict[str, Any]]
+    external_task_id: str
+    rule_lookup: BillingRuleLookupResult | None
+    upstream_payload: dict[str, Any] | None = None
+    upstream_headers: dict[str, str] | None = None
+    upstream_status_code: int | None = None

src/services/gemini_files_mapping.py

@@ -1,21 +1,41 @@
 """
-Gemini Files API - 文件与 Key 绑定缓存
+Gemini Files API - 文件与 Key 绑定映射服务
 
 用于在上传文件后记录 file_id -> provider_key_id，
 并在后续 generateContent 请求中优先使用同一 Key。
+
+存储策略：
+- 数据库（持久化）：主存储，支持服务重启后恢复
+- Redis（缓存）：加速读取，TTL=48小时
+
+读取策略：
+1. 先查 Redis 缓存
+2. 缓存未命中时回查数据库
+3. 从数据库读取后回填缓存
+
+清理策略：
+- 数据库中 expires_at 过期的记录由定时任务清理
+- Redis 缓存由 TTL 自动过期
 """
 
 from __future__ import annotations
 
-from typing import Any, Dict, Optional, Set
+import uuid
+from datetime import datetime, timedelta, timezone
+from typing import Any
+
+from sqlalchemy import delete
+from sqlalchemy.orm import Session
 
 from src.core.cache_service import CacheService
+from src.core.logger import logger
 
 FILE_MAPPING_TTL_SECONDS = 60 * 60 * 48  # 48小时
 FILE_MAPPING_CACHE_PREFIX = "gemini_files:key"
 
 
 def _normalize_file_name(file_name: str) -> str:
+    """规范化文件名，确保以 files/ 开头"""
     name = (file_name or "").strip()
     if not name:
         return ""
@@ -23,31 +43,294 @@ def _normalize_file_name(file_name: str) -> str:
 
 
 def build_file_mapping_key(file_name: str) -> str:
+    """构建 Redis 缓存键"""
     normalized = _normalize_file_name(file_name)
     return f"{FILE_MAPPING_CACHE_PREFIX}:{normalized}" if normalized else ""
 
 
-async def store_file_key_mapping(file_name: str, key_id: str) -> None:
-    cache_key = build_file_mapping_key(file_name)
-    if not cache_key or not key_id:
+# =============================================================================
+# 异步接口（用于请求处理流程）
+# =============================================================================
+
+
+async def store_file_key_mapping(
+    file_name: str,
+    key_id: str,
+    user_id: str | None = None,
+    display_name: str | None = None,
+    mime_type: str | None = None,
+    source_hash: str | None = None,
+) -> None:
+    """
+    存储文件→Key 映射（同时写入 Redis 和数据库）
+
+    Args:
+        file_name: 文件名（如 files/abc123）
+        key_id: Provider Key ID
+        user_id: 用户 ID（可选，用于权限验证）
+        display_name: 文件显示名（可选）
+        mime_type: 文件 MIME 类型（可选）
+        source_hash: 源文件哈希（可选，用于关联相同源文件的不同上传）
+    """
+    normalized_name = _normalize_file_name(file_name)
+    if not normalized_name or not key_id:
         return
+
+    # 1. 写入 Redis 缓存
+    cache_key = build_file_mapping_key(normalized_name)
     await CacheService.set(cache_key, str(key_id), ttl_seconds=FILE_MAPPING_TTL_SECONDS)
 
+    # 2. 写入数据库（异步执行，不阻塞主流程）
+    try:
+        await _store_to_database(
+            file_name=normalized_name,
+            key_id=key_id,
+            user_id=user_id,
+            display_name=display_name,
+            mime_type=mime_type,
+            source_hash=source_hash,
+        )
+    except Exception as e:
+        # 数据库写入失败只记录警告，不影响主流程
+        logger.warning(f"Failed to persist Gemini file mapping to database: {e}")
+
+
+async def _store_to_database(
+    file_name: str,
+    key_id: str,
+    user_id: str | None = None,
+    display_name: str | None = None,
+    mime_type: str | None = None,
+    source_hash: str | None = None,
+) -> None:
+    """将映射写入数据库"""
+    from src.database import get_db_context
+    from src.models.database import GeminiFileMapping
+
+    now = datetime.now(timezone.utc)
+    expires_at = now + timedelta(hours=48)
+
+    with get_db_context() as db:
+        # 使用 upsert 逻辑：存在则更新，不存在则插入
+        existing = (
+            db.query(GeminiFileMapping).filter(GeminiFileMapping.file_name == file_name).first()
+        )
+
+        if existing:
+            # 更新现有记录
+            existing.key_id = key_id
+            existing.user_id = user_id
+            existing.display_name = display_name
+            existing.mime_type = mime_type
+            existing.source_hash = source_hash
+            existing.expires_at = expires_at
+        else:
+            # 插入新记录
+            mapping = GeminiFileMapping(
+                id=str(uuid.uuid4()),
+                file_name=file_name,
+                key_id=key_id,
+                user_id=user_id,
+                display_name=display_name,
+                mime_type=mime_type,
+                source_hash=source_hash,
+                created_at=now,
+                expires_at=expires_at,
+            )
+            db.add(mapping)
+
+        db.commit()
+
 
 async def get_file_key_mapping(file_name: str) -> str | None:
-    cache_key = build_file_mapping_key(file_name)
-    if not cache_key:
+    """
+    获取文件→Key 映射
+
+    读取策略：
+    1. 先查 Redis 缓存
+    2. 缓存未命中时回查数据库
+    3. 从数据库读取后回填缓存
+
+    Args:
+        file_name: 文件名（如 files/abc123）
+
+    Returns:
+        Provider Key ID，如果不存在或已过期则返回 None
+    """
+    normalized_name = _normalize_file_name(file_name)
+    if not normalized_name:
         return None
-    value = await CacheService.get(cache_key)
-    if value:
-        return str(value)
+
+    cache_key = build_file_mapping_key(normalized_name)
+
+    # 1. 先查 Redis 缓存
+    cached_value = await CacheService.get(cache_key)
+    if cached_value:
+        return str(cached_value)
+
+    # 2. 缓存未命中，回查数据库
+    key_id = await _get_from_database(normalized_name)
+
+    if key_id:
+        # 3. 回填缓存（使用剩余有效期或默认 TTL）
+        await CacheService.set(cache_key, key_id, ttl_seconds=FILE_MAPPING_TTL_SECONDS)
+        logger.debug(f"Gemini file mapping cache refilled from database: {normalized_name}")
+
+    return key_id
+
+
+async def _get_from_database(file_name: str) -> str | None:
+    """从数据库查询映射"""
+    from src.database import get_db_context
+    from src.models.database import GeminiFileMapping
+
+    now = datetime.now(timezone.utc)
+
+    try:
+        with get_db_context() as db:
+            mapping = (
+                db.query(GeminiFileMapping)
+                .filter(
+                    GeminiFileMapping.file_name == file_name,
+                    GeminiFileMapping.expires_at > now,  # 只返回未过期的
+                )
+                .first()
+            )
+
+            if mapping:
+                return str(mapping.key_id)
+    except Exception as e:
+        logger.warning(f"Failed to query Gemini file mapping from database: {e}")
+
     return None
 
 
+async def get_all_key_ids_for_file(file_name: str) -> list[str]:
+    """
+    获取支持指定文件的所有 Key ID 列表
+
+    当同一个源文件被上传到多个 Key 时，返回所有可用的 Key ID。
+    这允许系统在首选 Key 不可用时选择其他 Key。
+
+    Args:
+        file_name: 文件名（如 files/abc123）
+
+    Returns:
+        所有支持该文件的 Key ID 列表（包括原始映射和具有相同 source_hash 的映射）
+    """
+    from src.database import get_db_context
+    from src.models.database import GeminiFileMapping
+
+    normalized_name = _normalize_file_name(file_name)
+    if not normalized_name:
+        return []
+
+    now = datetime.now(timezone.utc)
+
+    try:
+        with get_db_context() as db:
+            # 首先获取原始映射
+            original_mapping = (
+                db.query(GeminiFileMapping)
+                .filter(
+                    GeminiFileMapping.file_name == normalized_name,
+                    GeminiFileMapping.expires_at > now,
+                )
+                .first()
+            )
+
+            if not original_mapping:
+                return []
+
+            key_ids = [str(original_mapping.key_id)]
+
+            # 如果有 source_hash，查找所有具有相同 source_hash 的映射
+            if original_mapping.source_hash:
+                related_mappings = (
+                    db.query(GeminiFileMapping)
+                    .filter(
+                        GeminiFileMapping.source_hash == original_mapping.source_hash,
+                        GeminiFileMapping.expires_at > now,
+                        GeminiFileMapping.file_name != normalized_name,  # 排除原始映射
+                    )
+                    .all()
+                )
+
+                for mapping in related_mappings:
+                    kid = str(mapping.key_id)
+                    if kid not in key_ids:
+                        key_ids.append(kid)
+
+            return key_ids
+    except Exception as e:
+        logger.warning(f"Failed to query related Gemini file mappings: {e}")
+        return []
+
+
 async def delete_file_key_mapping(file_name: str) -> None:
-    cache_key = build_file_mapping_key(file_name)
-    if cache_key:
-        await CacheService.delete(cache_key)
+    """
+    删除文件→Key 映射（同时从 Redis 和数据库删除）
+
+    Args:
+        file_name: 文件名（如 files/abc123）
+    """
+    normalized_name = _normalize_file_name(file_name)
+    if not normalized_name:
+        return
+
+    # 1. 从 Redis 删除
+    cache_key = build_file_mapping_key(normalized_name)
+    await CacheService.delete(cache_key)
+
+    # 2. 从数据库删除
+    try:
+        await _delete_from_database(normalized_name)
+    except Exception as e:
+        logger.warning(f"Failed to delete Gemini file mapping from database: {e}")
+
+
+async def _delete_from_database(file_name: str) -> None:
+    """从数据库删除映射"""
+    from src.database import get_db_context
+    from src.models.database import GeminiFileMapping
+
+    with get_db_context() as db:
+        db.execute(delete(GeminiFileMapping).where(GeminiFileMapping.file_name == file_name))
+        db.commit()
+
+
+# =============================================================================
+# 同步接口（用于定时任务等场景）
+# =============================================================================
+
+
+def cleanup_expired_mappings(db: Session) -> int:
+    """
+    清理过期的文件映射记录（同步方法，供定时任务调用）
+
+    Args:
+        db: 数据库会话
+
+    Returns:
+        删除的记录数
+    """
+    from src.models.database import GeminiFileMapping
+
+    now = datetime.now(timezone.utc)
+
+    result = db.execute(delete(GeminiFileMapping).where(GeminiFileMapping.expires_at <= now))
+    db.commit()
+
+    deleted_count = result.rowcount
+    if deleted_count > 0:
+        logger.info(f"Cleaned up {deleted_count} expired Gemini file mappings")
+
+    return deleted_count
+
+
+# =============================================================================
+# 请求解析工具函数
+# =============================================================================
 
 
 def _extract_file_name_from_uri(file_uri: str) -> str | None:

src/services/model/fetch_scheduler.py

@@ -39,6 +39,10 @@ MAX_CONCURRENT_REQUESTS = 5
 # 单个 Key 处理的超时时间（秒）
 KEY_FETCH_TIMEOUT_SECONDS = 120
 
+# 模型获取 HTTP 请求超时时间（秒）
+# 使用较短的超时（10秒），避免不支持 /models 端点的提供商长时间阻塞
+MODEL_FETCH_HTTP_TIMEOUT = 10.0
+
 # 上游模型缓存 TTL（与定时任务间隔保持一致）
 UPSTREAM_MODELS_CACHE_TTL_SECONDS = MODEL_FETCH_INTERVAL_MINUTES * 60
 
@@ -260,7 +264,48 @@ class ModelFetchScheduler:
             logger.exception(f"更新 Key {key_id} 错误信息失败")
 
     async def _fetch_models_for_key_by_id(self, key_id: str) -> str:
-        """根据 Key ID 获取模型并更新，返回结果状态"""
+        """
+        根据 Key ID 获取模型并更新，返回结果状态
+
+        优化：分两个阶段处理，HTTP 请求期间不持有数据库连接，避免阻塞其他请求
+        """
+        # ========== 阶段 1：准备数据（短暂持有连接）==========
+        fetch_context = self._prepare_fetch_context(key_id)
+        if fetch_context is None:
+            return "skip"
+        if isinstance(fetch_context, str):
+            return fetch_context  # "error" or "skip"
+
+        key_id, provider_id, provider_name, api_key_value, endpoint_configs = fetch_context
+
+        # ========== 阶段 2：HTTP 请求（不持有数据库连接）==========
+        # 使用较短的超时时间（10秒），避免长时间阻塞
+        all_models, errors, has_success = await fetch_models_from_endpoints(
+            endpoint_configs, timeout=MODEL_FETCH_HTTP_TIMEOUT
+        )
+
+        # ========== 阶段 3：更新数据库（获取新连接）==========
+        return await self._update_key_after_fetch(
+            key_id=key_id,
+            provider_id=provider_id,
+            provider_name=provider_name,
+            all_models=all_models,
+            errors=errors,
+            has_success=has_success,
+        )
+
+    def _prepare_fetch_context(
+        self, key_id: str
+    ) -> tuple[str, str, str, str, list[dict]] | str | None:
+        """
+        准备获取模型所需的上下文数据
+
+        Returns:
+            - tuple: (key_id, provider_id, provider_name, api_key_value, endpoint_configs)
+            - "skip": 跳过该 Key
+            - "error": 出错
+            - None: Key 不存在
+        """
         with create_session() as db:
             key = (
                 db.query(ProviderAPIKey)
@@ -271,142 +316,154 @@ class ModelFetchScheduler:
 
             if not key:
                 logger.warning(f"Key {key_id} 不存在，跳过")
-                return "skip"
+                return None
 
             if not key.is_active or not key.auto_fetch_models:
                 logger.debug(f"Key {key_id} 已禁用或关闭自动获取，跳过")
                 return "skip"
 
-            try:
-                result = await self._fetch_models_for_key(db, key)
+            now = datetime.now(timezone.utc)
+            provider_id = key.provider_id
+
+            # 获取 Provider 和 Endpoints
+            provider = (
+                db.query(Provider)
+                .options(joinedload(Provider.endpoints))
+                .filter(Provider.id == provider_id)
+                .first()
+            )
+
+            if not provider:
+                logger.warning(f"Provider {provider_id} 不存在，跳过 Key {key.id}")
+                key.last_models_fetch_error = "Provider not found"
+                key.last_models_fetch_at = now
                 db.commit()
-                return result
+                return "error"
+
+            # Vertex AI 类型不支持自动获取模型
+            auth_type = getattr(key, "auth_type", "api_key") or "api_key"
+            if auth_type == "vertex_ai":
+                key.last_models_fetch_error = "auto_fetch_models 暂不支持 Vertex AI 类型的 Key"
+                key.last_models_fetch_at = now
+                db.commit()
+                logger.info(f"Key {key.id} 为 Vertex AI 类型，跳过自动获取模型")
+                return "skip"
+
+            # 解密 API Key
+            if not key.api_key:
+                logger.warning(f"Key {key.id} 没有 API Key，跳过")
+                key.last_models_fetch_error = "No API key configured"
+                key.last_models_fetch_at = now
+                db.commit()
+                return "error"
+
+            try:
+                api_key_value = crypto_service.decrypt(key.api_key)
             except Exception:
-                db.rollback()
-                raise
+                logger.error(f"解密 Key {key.id} 失败")
+                key.last_models_fetch_error = "Decrypt error"
+                key.last_models_fetch_at = now
+                db.commit()
+                return "error"
 
-    async def _fetch_models_for_key(
+            # 构建 api_format -> endpoint 映射
+            format_to_endpoint: dict[str, object] = {}
+            for endpoint in provider.endpoints:  # type: ignore[attr-defined]
+                if endpoint.is_active:
+                    format_to_endpoint[endpoint.api_format] = endpoint
+
+            if not format_to_endpoint:
+                logger.warning(f"Provider {provider.name} 没有活跃的端点，跳过 Key {key.id}")
+                key.last_models_fetch_error = "No active endpoints"
+                key.last_models_fetch_at = now
+                db.commit()
+                return "error"
+
+            # 使用公共函数构建所有格式的端点配置
+            endpoint_configs = build_all_format_configs(api_key_value, format_to_endpoint)  # type: ignore[arg-type]
+
+            return (key_id, provider_id, provider.name, api_key_value, endpoint_configs)
+
+    async def _update_key_after_fetch(
         self,
-        db: Session,
-        key: ProviderAPIKey,
+        key_id: str,
+        provider_id: str,
+        provider_name: str,
+        all_models: list[dict],
+        errors: list[str],
+        has_success: bool,
     ) -> str:
-        """为单个 Key 获取模型并更新 allowed_models，返回结果状态"""
+        """
+        HTTP 请求完成后更新数据库
+
+        使用新的数据库连接来更新 Key 的 allowed_models
+        """
         now = datetime.now(timezone.utc)
-        provider_id = key.provider_id
 
-        # 获取 Provider 和 Endpoints
-        provider = (
-            db.query(Provider)
-            .options(joinedload(Provider.endpoints))
-            .filter(Provider.id == provider_id)
-            .first()
-        )
+        with create_session() as db:
+            # 重新获取 Key（因为之前的连接已关闭）
+            key = db.query(ProviderAPIKey).filter(ProviderAPIKey.id == key_id).first()
+            if not key:
+                logger.warning(f"Key {key_id} 在更新时不存在")
+                return "error"
 
-        if not provider:
-            logger.warning(f"Provider {provider_id} 不存在，跳过 Key {key.id}")
-            key.last_models_fetch_error = "Provider not found"
+            # 记录获取时间
             key.last_models_fetch_at = now
-            return "error"
 
-        # Vertex AI 类型不支持自动获取模型（需要使用 Service Account 认证）
-        auth_type = getattr(key, "auth_type", "api_key") or "api_key"
-        if auth_type == "vertex_ai":
-            key.last_models_fetch_error = "auto_fetch_models 暂不支持 Vertex AI 类型的 Key"
-            key.last_models_fetch_at = now
-            logger.info(f"Key {key.id} 为 Vertex AI 类型，跳过自动获取模型")
-            return "skip"
+            # 如果没有任何成功的响应，不更新 allowed_models（保留旧数据）
+            if not has_success:
+                error_msg = "; ".join(errors) if errors else "All endpoints failed"
+                key.last_models_fetch_error = error_msg
+                logger.warning(
+                    f"Provider {provider_name} Key {key.id} 所有端点获取失败，保留现有模型列表"
+                )
+                db.commit()
+                return "error"
 
-        # 解密 API Key
-        if not key.api_key:
-            logger.warning(f"Key {key.id} 没有 API Key，跳过")
-            key.last_models_fetch_error = "No API key configured"
-            key.last_models_fetch_at = now
-            return "error"
+            # 有成功的响应，清除错误状态
+            key.last_models_fetch_error = None
 
-        try:
-            api_key_value = crypto_service.decrypt(key.api_key)
-        except Exception:
-            # 不记录异常详情，避免泄露密钥信息
-            logger.error(f"解密 Key {key.id} 失败")
-            key.last_models_fetch_error = "Decrypt error"
-            key.last_models_fetch_at = now
-            return "error"
+            # 去重获取模型 ID 列表
+            fetched_model_ids: set[str] = set()
+            for model in all_models:
+                model_id = model.get("id")
+                if model_id:
+                    fetched_model_ids.add(model_id)
 
-        # 构建 api_format -> endpoint 映射
-        format_to_endpoint: dict[str, object] = {}
-        for endpoint in provider.endpoints:  # type: ignore[attr-defined]
-            if endpoint.is_active:
-                format_to_endpoint[endpoint.api_format] = endpoint
-
-        if not format_to_endpoint:
-            logger.warning(f"Provider {provider.name} 没有活跃的端点，跳过 Key {key.id}")
-            key.last_models_fetch_error = "No active endpoints"
-            key.last_models_fetch_at = now
-            return "error"
-
-        # 使用公共函数构建所有格式的端点配置
-        endpoint_configs = build_all_format_configs(api_key_value, format_to_endpoint)  # type: ignore[arg-type]
-
-        # 并发获取模型
-        all_models, errors, has_success = await fetch_models_from_endpoints(endpoint_configs)
-
-        # 记录获取时间
-        key.last_models_fetch_at = now
-
-        # 如果没有任何成功的响应，不更新 allowed_models（保留旧数据）
-        if not has_success:
-            # 所有端点都失败时，记录错误
-            error_msg = "; ".join(errors) if errors else "All endpoints failed"
-            key.last_models_fetch_error = error_msg
-            logger.warning(
-                f"Provider {provider.name} Key {key.id} 所有端点获取失败，保留现有模型列表"
-            )
-            return "error"
-
-        # 有成功的响应，清除错误状态（部分失败不算失败）
-        key.last_models_fetch_error = None
-
-        # 去重获取模型 ID 列表
-        fetched_model_ids: set[str] = set()
-        for model in all_models:
-            model_id = model.get("id")
-            if model_id:
-                fetched_model_ids.add(model_id)
-
-        logger.info(
-            f"Provider {provider.name} Key {key.id} 获取到 {len(fetched_model_ids)} 个唯一模型"
-        )
-
-        # 写入上游模型缓存（按 model id + api_format 去重后的完整模型信息）
-        seen_keys: set[str] = set()
-        unique_models: list[dict] = []
-        for model in all_models:
-            model_id = model.get("id")
-            api_format = model.get("api_format", "")
-            unique_key = f"{model_id}:{api_format}"
-            if model_id and unique_key not in seen_keys:
-                seen_keys.add(unique_key)
-                unique_models.append(model)
-        await set_upstream_models_to_cache(
-            provider_id,  # type: ignore[arg-type]
-            key.id,  # type: ignore[arg-type]
-            unique_models,
-        )
-
-        # 更新 allowed_models（保留 locked_models）
-        has_changed = self._update_key_allowed_models(key, fetched_model_ids)
-
-        # 如果白名单有变化，触发缓存失效和自动关联检查
-        if has_changed and provider_id:
-            from src.services.model.global_model import on_key_allowed_models_changed
-
-            await on_key_allowed_models_changed(
-                db=db,
-                provider_id=provider_id,
-                allowed_models=list(key.allowed_models or []),
+            logger.info(
+                f"Provider {provider_name} Key {key.id} 获取到 {len(fetched_model_ids)} 个唯一模型"
             )
 
-        return "success"
+            # 写入上游模型缓存（按 model id + api_format 去重后的完整模型信息）
+            seen_keys: set[str] = set()
+            unique_models: list[dict] = []
+            for model in all_models:
+                model_id = model.get("id")
+                api_format = model.get("api_format", "")
+                unique_key = f"{model_id}:{api_format}"
+                if model_id and unique_key not in seen_keys:
+                    seen_keys.add(unique_key)
+                    unique_models.append(model)
+            await set_upstream_models_to_cache(provider_id, key.id, unique_models)
+
+            # 更新 allowed_models（保留 locked_models）
+            has_changed = self._update_key_allowed_models(key, fetched_model_ids)
+
+            db.commit()
+
+            # 如果白名单有变化，触发缓存失效和自动关联检查
+            if has_changed and provider_id:
+                from src.services.model.global_model import on_key_allowed_models_changed
+
+                # 使用新会话处理后续操作
+                with create_session() as db2:
+                    await on_key_allowed_models_changed(
+                        db=db2,
+                        provider_id=provider_id,
+                        allowed_models=list(key.allowed_models or []),
+                    )
+
+            return "success"
 
     def _update_key_allowed_models(self, key: ProviderAPIKey, fetched_model_ids: set[str]) -> bool:
         """

src/services/orchestration/candidate_resolver.py

@@ -156,6 +156,8 @@ class CandidateResolver:
         user_id: str,
         user_api_key: ApiKey,
         required_capabilities: dict[str, bool] | None = None,
+        *,
+        expand_retries: bool = True,
     ) -> dict[tuple[int, int], str]:
         """
         为所有候选预先创建 available 状态记录（批量插入优化）
@@ -211,9 +213,12 @@ class CandidateResolver:
                 candidate_record_map[(candidate_index, 0)] = record_id
             else:
                 # max_retries 已从 Endpoint 迁移到 Provider（Endpoint 仍可能保留旧字段用于兼容）
-                max_retries_for_candidate = (
-                    int(provider.max_retries or 2) if candidate.is_cached else 1
-                )
+                if not expand_retries:
+                    max_retries_for_candidate = 1
+                else:
+                    max_retries_for_candidate = (
+                        int(provider.max_retries or 2) if candidate.is_cached else 1
+                    )
 
                 for retry_index in range(max_retries_for_candidate):
                     record_id = str(uuid.uuid4())

src/services/provider_ops/service.py

@@ -38,6 +38,19 @@ BALANCE_CACHE_TTL = 86400
 # 认证失败缓存 TTL（60 秒，避免频繁重试但允许用户修正后快速重试）
 AUTH_FAILED_CACHE_TTL = 60
 
+# 后台余额刷新并发限制（避免启动时耗尽连接池）
+# 使用较小的值（3）确保不会对连接池造成过大压力
+_balance_refresh_semaphore: asyncio.Semaphore | None = None
+
+
+def _get_balance_refresh_semaphore() -> asyncio.Semaphore:
+    """获取余额刷新信号量（延迟初始化）"""
+    global _balance_refresh_semaphore
+    if _balance_refresh_semaphore is None:
+        # 限制为 3 个并发，确保后台任务不会占用太多连接
+        _balance_refresh_semaphore = asyncio.Semaphore(3)
+    return _balance_refresh_semaphore
+
 
 def _get_batch_balance_concurrency() -> int:
     """
@@ -98,6 +111,44 @@ class ProviderOpsService:
         # 连接器缓存 {provider_id: ProviderConnector}
         self._connectors: dict[str, ProviderConnector] = {}
 
+    def _release_db_connection_before_await(self) -> None:
+        """
+        Release pooled DB connection before long awaits (network/Redis).
+
+        SQLAlchemy Session will keep a connection checked out while a transaction is open,
+        even for read-only queries. In async code, this can exhaust the pool if we `await`
+        network I/O while holding that transaction.
+
+        Safety:
+        - Only commits when the session has no pending changes (new/dirty/deleted).
+        - Temporarily disables expire_on_commit to avoid unexpected lazy reloads.
+        """
+        try:
+            has_pending_changes = bool(self.db.new) or bool(self.db.dirty) or bool(self.db.deleted)
+        except Exception:
+            has_pending_changes = False
+
+        if has_pending_changes:
+            return
+
+        try:
+            if not self.db.in_transaction():
+                return
+        except Exception:
+            return
+
+        original_expire_on_commit = getattr(self.db, "expire_on_commit", True)
+        self.db.expire_on_commit = False
+        try:
+            self.db.commit()
+        except Exception:
+            try:
+                self.db.rollback()
+            except Exception:
+                pass
+        finally:
+            self.db.expire_on_commit = original_expire_on_commit
+
     # ==================== 配置管理 ====================
 
     def get_config(self, provider_id: str) -> ProviderOpsConfig | None:
@@ -251,6 +302,9 @@ class ProviderOpsService:
         if not actual_credentials:
             return False, "未提供凭据"
 
+        # Avoid holding a DB connection while awaiting network I/O.
+        self._release_db_connection_before_await()
+
         # 建立连接
         logger.info(
             f"尝试连接: provider_id={provider_id}, "
@@ -333,6 +387,8 @@ class ProviderOpsService:
                 )
             connector = self._connectors.get(provider_id)
 
+        # Avoid holding a DB connection while awaiting authentication checks.
+        self._release_db_connection_before_await()
         if not connector or not await connector.is_authenticated():
             return ActionResult(
                 status=ActionStatus.AUTH_EXPIRED,
@@ -373,6 +429,9 @@ class ProviderOpsService:
         # 创建操作实例
         action = architecture.get_action(action_type, merged_config)
 
+        # Avoid holding a DB connection while awaiting the upstream action.
+        self._release_db_connection_before_await()
+
         # 执行操作
         async with connector.get_client() as client:
             result = await action.execute(client)
@@ -422,6 +481,9 @@ class ProviderOpsService:
         Returns:
             操作结果（可能是缓存的）
         """
+        # Avoid holding a DB connection while awaiting Redis/cache I/O.
+        self._release_db_connection_before_await()
+
         # 尝试从缓存获取
         cached = await self._get_cached_balance(provider_id)
 
@@ -453,7 +515,20 @@ class ProviderOpsService:
 
         注意：这是一个后台任务，使用独立的短生命周期 session，
         避免长时间占用连接池资源。
+
+        使用信号量限制并发数，避免启动时多个刷新任务同时运行导致连接池耗尽。
         """
+        semaphore = _get_balance_refresh_semaphore()
+
+        # 尝试获取信号量，如果无法立即获取则跳过本次刷新
+        # 这样可以避免在连接池紧张时阻塞
+        try:
+            # 使用 wait_for 设置超时，避免无限等待
+            await asyncio.wait_for(semaphore.acquire(), timeout=5.0)
+        except asyncio.TimeoutError:
+            logger.debug(f"异步刷新余额跳过（并发限制）: provider_id={provider_id}")
+            return
+
         db = None
         try:
             # 后台任务需要创建独立的 session，因为原请求的 session 可能已关闭
@@ -469,6 +544,8 @@ class ProviderOpsService:
                     db.close()
                 except Exception:
                     pass
+            # 释放信号量
+            semaphore.release()
 
     async def _clear_balance_cache(self, provider_id: str) -> None:
         """清除余额缓存"""
@@ -762,6 +839,9 @@ class ProviderOpsService:
         if not provider_ids:
             return {}
 
+        # Release the DB connection before awaiting many async cache refreshes.
+        self._release_db_connection_before_await()
+
         # 使用信号量限制并发数，避免同时发起过多请求耗尽连接池
         concurrency = _get_batch_balance_concurrency()
         semaphore = asyncio.Semaphore(concurrency)
@@ -822,6 +902,9 @@ class ProviderOpsService:
 
         from src.utils.ssl_utils import get_ssl_context
 
+        # Avoid holding a DB connection while awaiting verify pre-processing / network.
+        self._release_db_connection_before_await()
+
         # 移除 base_url 末尾的斜杠
         base_url = base_url.rstrip("/")
 

src/services/system/config.py

@@ -136,6 +136,11 @@ class SystemConfigService:
             "value": [],
             "description": "邮箱后缀列表，配合 email_suffix_mode 使用",
         },
+        # 格式转换开关
+        "enable_format_conversion": {
+            "value": False,
+            "description": "全局格式转换开关：开启时强制允许所有提供商的格式转换；关闭时由各提供商自行决定",
+        },
         "audit_log_retention_days": {
             "value": 30,
             "description": "审计日志保留天数，超过此天数的审计日志将被自动清理",
@@ -358,6 +363,11 @@ class SystemConfigService:
         """获取敏感请求头列表"""
         return cls.get_config(db, "sensitive_headers", [])
 
+    @classmethod
+    def is_format_conversion_enabled(cls, db: Session) -> bool:
+        """检查全局格式转换是否启用"""
+        return bool(cls.get_config(db, "enable_format_conversion", True))
+
     @classmethod
     def mask_sensitive_headers(cls, db: Session, headers: dict[str, Any]) -> dict[str, Any]:
         """脱敏敏感请求头"""

src/services/system/maintenance_scheduler.py

@@ -8,6 +8,7 @@
 - 审计日志清理：定期清理过期的审计日志
 - 连接池监控：定期检查数据库连接池状态
 - Pending 状态清理：清理异常的 Pending 状态记录
+- Gemini 文件映射清理：清理过期的 Gemini 文件→Key 映射
 
 使用 APScheduler 进行任务调度，支持时区配置。
 """
@@ -103,6 +104,14 @@ class MaintenanceScheduler:
             name="审计日志清理",
         )
 
+        # Gemini 文件映射清理 - 每小时执行
+        scheduler.add_interval_job(
+            self._scheduled_gemini_file_mapping_cleanup,
+            hours=1,
+            job_id="gemini_file_mapping_cleanup",
+            name="Gemini文件映射清理",
+        )
+
         # Provider 签到任务 - 凌晨 1:05 执行
         scheduler.add_cron_job(
             self._scheduled_provider_checkin,
@@ -117,8 +126,9 @@ class MaintenanceScheduler:
 
     async def _run_startup_tasks(self) -> None:
         """启动时执行的初始化任务"""
-        # 延迟一点执行，确保系统完全启动
-        await asyncio.sleep(2)
+        # 延迟执行，等待系统完全启动（Redis 连接、其他后台任务稳定）
+        # 增加延迟时间避免与 UsageQueueConsumer 等后台任务竞争数据库连接
+        await asyncio.sleep(10)
 
         try:
             logger.info("启动时执行首次清理任务...")
@@ -170,6 +180,10 @@ class MaintenanceScheduler:
         """审计日志清理任务（定时调用）"""
         await self._perform_audit_cleanup()
 
+    async def _scheduled_gemini_file_mapping_cleanup(self) -> None:
+        """Gemini 文件映射清理任务（定时调用）"""
+        await self._perform_gemini_file_mapping_cleanup()
+
     async def _scheduled_provider_checkin(self) -> None:
         """Provider 签到任务（定时调用）"""
         await self._perform_provider_checkin()
@@ -483,6 +497,26 @@ class MaintenanceScheduler:
         finally:
             db.close()
 
+    async def _perform_gemini_file_mapping_cleanup(self) -> None:
+        """清理过期的 Gemini 文件映射记录"""
+        db = create_session()
+        try:
+            from src.services.gemini_files_mapping import cleanup_expired_mappings
+
+            deleted_count = cleanup_expired_mappings(db)
+
+            if deleted_count > 0:
+                logger.info(f"清理了 {deleted_count} 条过期的 Gemini 文件映射")
+
+        except Exception as e:
+            logger.exception(f"Gemini 文件映射清理失败: {e}")
+            try:
+                db.rollback()
+            except Exception:
+                pass
+        finally:
+            db.close()
+
     async def _perform_provider_checkin(self) -> None:
         """执行 Provider 签到任务
 
@@ -508,8 +542,21 @@ class MaintenanceScheduler:
 
             logger.info(f"开始执行 Provider 签到，共 {len(provider_ids)} 个...")
 
-            # 创建 ProviderOpsService 并执行批量余额查询（会触发签到）
-            service = ProviderOpsService(db)
+            # 释放主 session 的连接，避免在整个签到期间占用连接池
+            # （后续每个 provider 将使用独立短生命周期 session）
+            try:
+                if db.in_transaction():
+                    db.commit()
+            except Exception:
+                try:
+                    db.rollback()
+                except Exception:
+                    pass
+            try:
+                db.close()
+            except Exception:
+                pass
+            db = None
 
             # 使用信号量限制并发，避免同时发起过多请求
             concurrency = 3  # 签到任务并发数
@@ -518,7 +565,9 @@ class MaintenanceScheduler:
             async def _checkin_provider(provider_id: str) -> tuple[str, bool, str]:
                 """执行单个 Provider 的签到"""
                 async with semaphore:
+                    task_db = create_session()
                     try:
+                        service = ProviderOpsService(task_db)
                         # 触发余额查询（会先执行签到）
                         result = await service.query_balance(provider_id)
                         # 检查签到结果
@@ -537,6 +586,11 @@ class MaintenanceScheduler:
                     except Exception as e:
                         logger.warning(f"Provider {provider_id} 签到失败: {e}")
                         return provider_id, False, str(e)
+                    finally:
+                        try:
+                            task_db.close()
+                        except Exception:
+                            pass
 
             # 并行执行签到
             tasks = [_checkin_provider(pid) for pid in provider_ids]
@@ -556,7 +610,8 @@ class MaintenanceScheduler:
         except Exception as e:
             logger.exception(f"Provider 签到任务执行失败: {e}")
         finally:
-            db.close()
+            if db is not None:
+                db.close()
 
     async def _perform_cleanup(self) -> None:
         """执行清理任务"""

src/services/task/__init__.py

@@ -1,25 +1,13 @@
 """
-异步任务服务层
+任务服务层（Phase2）
 
-提供视频/图片/音频等异步任务的：
-- 提交阶段故障转移（AsyncTaskOrchestrator）
-- 终态计费与 Usage 写入（VideoTelemetry 等）
+统一任务框架相关的应用层入口：
+- 候选提交阶段：`services.candidate.CandidateService`
+- 终态结算：`services.task.application.TaskApplicationService`
 """
 
-from .orchestrator import (
-    AllCandidatesFailedError,
-    AsyncTaskOrchestrator,
-    CandidateSubmissionError,
-    CandidateUnsupportedError,
-    SubmitOutcome,
-    UpstreamClientRequestError,
-)
+from .application import TaskApplicationService
 
 __all__ = [
-    "AsyncTaskOrchestrator",
-    "SubmitOutcome",
-    "AllCandidatesFailedError",
-    "UpstreamClientRequestError",
-    "CandidateUnsupportedError",
-    "CandidateSubmissionError",
+    "TaskApplicationService",
 ]

src/services/task/application.py

@@ -0,0 +1,312 @@
+from __future__ import annotations
+
+from datetime import datetime, timezone
+from typing import Any
+
+from sqlalchemy.orm import Session
+
+from src.config.settings import config
+from src.core.logger import logger
+from src.models.database import ApiKey, Provider, Usage, User, VideoTask
+from src.services.billing.dimension_collector_service import DimensionCollectorService
+from src.services.billing.formula_engine import BillingIncompleteError, FormulaEngine
+from src.services.billing.rule_service import BillingRuleService
+from src.services.usage.service import UsageService
+
+
+class TaskApplicationService:
+    """
+    TaskApplicationService (Phase2)
+
+    当前仅先收敛"终态结算"入口，用于替代旧版 VideoTelemetry 直写 Usage 的流程。
+    后续将扩展 submit/cancel 并迁移候选编排逻辑。
+    """
+
+    def __init__(self, db: Session, *, redis_client: Any | None = None) -> None:
+        self.db = db
+        self.redis = redis_client
+
+    async def finalize_video_task(self, task: VideoTask) -> bool:
+        """
+        更新视频任务的计费信息（轮询完成后调用）。
+
+        异步任务的计费流程：
+        1. 提交成功时：Usage 已结算（billing_status='settled'，费用=0）
+        2. 轮询完成时：更新实际费用（成功则计费，失败则保持0）
+
+        返回 True 表示成功更新，False 表示无需更新（如已是最终状态）
+        """
+        request_id = getattr(task, "request_id", None) or task.id
+
+        existing = self.db.query(Usage).filter(Usage.request_id == request_id).first()
+        if not existing:
+            # Usage 不存在，尝试创建并结算（兜底逻辑）
+            logger.warning(
+                "Usage not found for video task, creating fallback: task_id=%s request_id=%s",
+                task.id,
+                request_id,
+            )
+            return await self._create_fallback_usage(task, request_id)
+
+        # 检查是否已有计费更新标记（避免重复计费）
+        metadata = existing.request_metadata or {}
+        if metadata.get("billing_updated_at"):
+            logger.debug(
+                "Video task billing already updated: task_id=%s request_id=%s",
+                task.id,
+                request_id,
+            )
+            return False
+
+        # 计算异步任务总耗时（ms）
+        response_time_ms: int | None = None
+        if task.submitted_at and task.completed_at:
+            delta = task.completed_at - task.submitted_at
+            response_time_ms = int(delta.total_seconds() * 1000)
+
+        # === 收集计费维度 ===
+        base_dimensions: dict[str, Any] = {
+            "duration_seconds": task.duration_seconds,
+            "resolution": task.resolution,
+            "aspect_ratio": task.aspect_ratio,
+            "size": task.size or "",
+            "retry_count": task.retry_count,
+        }
+
+        collector_metadata: dict[str, Any] = {
+            "task": {
+                "id": task.id,
+                "external_task_id": task.external_task_id,
+                "model": task.model,
+                "duration_seconds": task.duration_seconds,
+                "resolution": task.resolution,
+                "aspect_ratio": task.aspect_ratio,
+                "size": task.size,
+                "retry_count": task.retry_count,
+                "video_size_bytes": task.video_size_bytes,
+            },
+            "result": {
+                "video_url": task.video_url,
+                "video_urls": task.video_urls or [],
+            },
+        }
+
+        dims = DimensionCollectorService(self.db).collect_dimensions(
+            api_format=task.provider_api_format,
+            task_type="video",
+            request=task.original_request_body or {},
+            response=(
+                (task.request_metadata or {}).get("poll_raw_response")
+                if isinstance(task.request_metadata, dict)
+                else None
+            ),
+            metadata=collector_metadata,
+            base_dimensions=base_dimensions,
+        )
+
+        # === 计算成本（优先使用冻结的 billing_rule_snapshot）===
+        rule_snapshot = None
+        if isinstance(task.request_metadata, dict):
+            rule_snapshot = task.request_metadata.get("billing_rule_snapshot")
+
+        expression = None
+        variables: dict[str, Any] | None = None
+        dimension_mappings: dict[str, dict[str, Any]] | None = None
+        rule_id = None
+        rule_name = None
+        rule_scope = None
+
+        if isinstance(rule_snapshot, dict) and rule_snapshot.get("status") == "ok":
+            rule_id = rule_snapshot.get("rule_id")
+            rule_name = rule_snapshot.get("rule_name")
+            rule_scope = rule_snapshot.get("scope")
+            expression = rule_snapshot.get("expression")
+            variables = rule_snapshot.get("variables") or {}
+            dimension_mappings = rule_snapshot.get("dimension_mappings") or {}
+        else:
+            lookup = BillingRuleService.find_rule(
+                self.db,
+                provider_id=task.provider_id,
+                model_name=task.model,
+                task_type="video",
+            )
+            if lookup:
+                rule = lookup.rule
+                rule_id = rule.id
+                rule_name = rule.name
+                rule_scope = getattr(lookup, "scope", None)
+                expression = rule.expression
+                variables = rule.variables or {}
+                dimension_mappings = rule.dimension_mappings or {}
+
+        billing_snapshot: dict[str, Any] = {
+            "schema_version": "1.0",
+            "rule_id": str(rule_id) if rule_id else None,
+            "rule_name": str(rule_name) if rule_name else None,
+            "scope": str(rule_scope) if rule_scope else None,
+            "expression": str(expression) if expression else None,
+            "dimensions_used": dims,
+            "missing_required": [],
+            "cost": 0.0,
+            "status": "no_rule",
+            "calculated_at": datetime.now(timezone.utc).isoformat(),
+        }
+
+        cost = 0.0
+        # 只有任务成功时才计费
+        if task.status == "completed" and expression:
+            engine = FormulaEngine()
+            try:
+                result = engine.evaluate(
+                    expression=str(expression),
+                    variables=variables,
+                    dimensions=dims,
+                    dimension_mappings=dimension_mappings,
+                    strict_mode=config.billing_strict_mode,
+                )
+                billing_snapshot["status"] = result.status
+                billing_snapshot["missing_required"] = result.missing_required
+                if result.status == "complete":
+                    cost = float(result.cost)
+                billing_snapshot["cost"] = cost
+            except BillingIncompleteError as exc:
+                # strict_mode=true：标记任务失败并隐藏产物，避免"免费放行"
+                task.status = "failed"
+                task.error_code = "billing_incomplete"
+                task.error_message = f"Missing required dimensions: {exc.missing_required}"
+                task.video_url = None
+                task.video_urls = None
+                billing_snapshot["status"] = "incomplete"
+                billing_snapshot["missing_required"] = exc.missing_required
+                billing_snapshot["cost"] = 0.0
+            except Exception as exc:
+                billing_snapshot["status"] = "incomplete"
+                billing_snapshot["error"] = str(exc)
+                billing_snapshot["cost"] = 0.0
+
+        # 回写到 task.request_metadata 便于审计/重算
+        # 重新赋值整个字典，确保 SQLAlchemy 检测到变更
+        metadata = dict(task.request_metadata) if task.request_metadata else {}
+        metadata["billing_snapshot"] = billing_snapshot
+        task.request_metadata = metadata
+
+        # === 更新已结算的 Usage 计费信息 ===
+        updated = UsageService.update_settled_billing(
+            self.db,
+            request_id=request_id,
+            total_cost_usd=cost,
+            request_cost_usd=cost,
+            status="completed" if task.status == "completed" else "failed",
+            status_code=200 if task.status == "completed" else 500,
+            error_message=(
+                None
+                if task.status == "completed"
+                else (task.error_message or task.error_code or "video_task_failed")
+            ),
+            response_time_ms=response_time_ms,
+            billing_snapshot=billing_snapshot,
+            extra_metadata={
+                "dimensions": dims,
+                "raw_response_ref": {
+                    "video_task_id": task.id,
+                    "field": "video_tasks.request_metadata.poll_raw_response",
+                },
+            },
+        )
+
+        if updated:
+            logger.debug(
+                "Updated video task billing: task_id=%s request_id=%s cost=%.6f",
+                task.id,
+                request_id,
+                cost,
+            )
+        else:
+            logger.warning(
+                "Failed to update video task billing (may already be updated): "
+                "task_id=%s request_id=%s",
+                task.id,
+                request_id,
+            )
+
+        return updated
+
+    async def _create_fallback_usage(self, task: VideoTask, request_id: str) -> bool:
+        """
+        兜底逻辑：当 Usage 不存在时创建完整记录。
+        这种情况理论上不应发生（submit 阶段已创建），但保留以防万一。
+        """
+        user_obj = self.db.query(User).filter(User.id == task.user_id).first()
+        api_key_obj = (
+            self.db.query(ApiKey).filter(ApiKey.id == task.api_key_id).first()
+            if task.api_key_id
+            else None
+        )
+        provider_obj = (
+            self.db.query(Provider).filter(Provider.id == task.provider_id).first()
+            if task.provider_id
+            else None
+        )
+        provider_name = provider_obj.name if provider_obj else "unknown"
+
+        # 计算响应时间
+        response_time_ms: int | None = None
+        if task.submitted_at and task.completed_at:
+            delta = task.completed_at - task.submitted_at
+            response_time_ms = int(delta.total_seconds() * 1000)
+
+        try:
+            await UsageService.record_usage_with_custom_cost(
+                db=self.db,
+                user=user_obj,
+                api_key=api_key_obj,
+                provider=provider_name,
+                model=task.model,
+                request_type="video",
+                total_cost_usd=0.0,  # 兜底记录不计费
+                request_cost_usd=0.0,
+                input_tokens=0,
+                output_tokens=0,
+                cache_creation_input_tokens=0,
+                cache_read_input_tokens=0,
+                api_format=task.client_api_format,
+                endpoint_api_format=task.provider_api_format,
+                has_format_conversion=bool(task.format_converted),
+                is_stream=False,
+                response_time_ms=response_time_ms,
+                first_byte_time_ms=None,
+                status_code=200 if task.status == "completed" else 500,
+                error_message=(
+                    None
+                    if task.status == "completed"
+                    else (task.error_message or task.error_code or "video_task_failed")
+                ),
+                metadata={
+                    "fallback_created": True,
+                    "video_task_id": task.id,
+                },
+                request_headers=(
+                    (task.request_metadata or {}).get("request_headers")
+                    if isinstance(task.request_metadata, dict)
+                    else None
+                ),
+                request_body=task.original_request_body,
+                provider_request_headers=None,
+                response_headers=None,
+                client_response_headers=None,
+                response_body=None,
+                request_id=request_id,
+                provider_id=task.provider_id,
+                provider_endpoint_id=task.endpoint_id,
+                provider_api_key_id=task.key_id,
+                status="completed" if task.status == "completed" else "failed",
+                target_model=None,
+            )
+            return True
+        except Exception as exc:
+            logger.exception(
+                "Failed to create fallback usage for video task=%s: %s",
+                task.id,
+                str(exc),
+            )
+            return False

src/services/task/context.py

@@ -0,0 +1,36 @@
+from __future__ import annotations
+
+from dataclasses import dataclass, field
+from enum import Enum
+
+
+class TaskMode(str, Enum):
+    SYNC = "sync"
+    ASYNC = "async"
+
+
+@dataclass(slots=True)
+class TaskContext:
+    """
+    TaskContext (pure DTO)
+
+    - Only primitive types / IDs
+    - Serializable & safe to pass across processes
+    """
+
+    request_id: str
+    task_type: str  # chat/cli/video/image/audio
+    task_mode: TaskMode
+
+    user_id: str
+    api_key_id: str
+
+    client_ip: str = ""
+    user_agent: str = ""
+    start_time: float = 0.0
+
+    api_format: str | None = None
+    model: str | None = None
+    mapped_model: str | None = None
+
+    capability_requirements: dict[str, bool] = field(default_factory=dict)

src/services/task/impl/__init__.py

@@ -1,3 +1,7 @@
-"""Task telemetry implementations for concrete task types (video/image/audio)."""
+"""Per-task-type implementations (Phase2).
+
+Currently includes:
+- video: polling adapter
+"""
 
 __all__ = []

src/services/task/impl/video_poller.py

@@ -0,0 +1,626 @@
+"""
+Video task poller adapter.
+
+Implements the video-specific poll/normalize/update logic used by TaskPollerService.
+
+优化：HTTP 请求期间不持有数据库连接，避免阻塞其他请求。
+采用三阶段处理：准备数据 -> HTTP 请求 -> 更新数据库。
+"""
+
+from __future__ import annotations
+
+import json
+from dataclasses import dataclass
+from datetime import datetime, timedelta, timezone
+from typing import Any
+
+from sqlalchemy.orm import Session
+
+from src.api.handlers.base.request_builder import ProviderAuthInfo, get_provider_auth
+from src.api.handlers.base.video_handler_base import (
+    normalize_gemini_operation_id,
+    sanitize_error_message,
+)
+from src.clients.http_client import HTTPClientPool
+from src.config.settings import config
+from src.core.api_format import (
+    build_upstream_headers_for_endpoint,
+    get_extra_headers_from_endpoint,
+    make_signature_key,
+)
+from src.core.api_format.conversion.internal_video import InternalVideoPollResult, VideoStatus
+from src.core.api_format.conversion.normalizers.gemini import GeminiNormalizer
+from src.core.api_format.conversion.normalizers.openai import OpenAINormalizer
+from src.core.crypto import crypto_service
+from src.core.logger import logger
+from src.database import create_session
+from src.models.database import ProviderAPIKey, ProviderEndpoint, VideoTask
+from src.services.task.application import TaskApplicationService
+
+
+@dataclass(slots=True)
+class VideoPollContext:
+    """视频轮询上下文，保存 HTTP 请求所需的数据（不依赖数据库会话）"""
+
+    task_id: str
+    external_task_id: str
+    provider_api_format: str
+    base_url: str
+    upstream_key: str
+    headers: dict[str, str]
+    # 用于更新任务的原始数据
+    poll_count: int
+    retry_count: int
+    poll_interval_seconds: int
+    max_poll_count: int
+    current_status: str
+
+
+# 永久性错误指示词（用于降级判断，不应重试）
+_PERMANENT_ERROR_INDICATORS = frozenset(
+    {
+        "not found",
+        "404",
+        "unauthorized",
+        "401",
+        "forbidden",
+        "403",
+        "invalid request",
+        "invalid api key",
+        "does not exist",
+    }
+)
+
+
+class PollHTTPError(RuntimeError):
+    """HTTP 轮询错误，携带状态码便于区分临时/永久错误"""
+
+    def __init__(self, status_code: int, message: str):
+        # 确保错误信息包含状态码
+        full_message = f"HTTP {status_code}: {message}" if message else f"HTTP {status_code}"
+        super().__init__(full_message)
+        self.status_code = status_code
+        self.original_message = message
+
+
+class VideoTaskPollerAdapter:
+    task_type = "video"
+
+    # scheduler
+    job_id = "task_poller:video"
+    job_name = "视频任务轮询"
+    interval_seconds = config.video_poll_interval_seconds
+
+    # distributed lock
+    lock_key = "task_poller:video:lock"
+    lock_ttl = 60
+
+    # execution
+    batch_size = config.video_poll_batch_size
+    concurrency = config.video_poll_concurrency
+    consecutive_failure_alert_threshold = 5
+    max_backoff_seconds = 300
+
+    def __init__(self) -> None:
+        self._openai_normalizer = OpenAINormalizer()
+        self._gemini_normalizer = GeminiNormalizer()
+
+    def sanitize_error_message(self, message: str) -> str:
+        return sanitize_error_message(message)
+
+    def list_due_task_ids(self, db: Session, *, now: datetime, limit: int) -> list[str]:
+        tasks = (
+            db.query(VideoTask)
+            .filter(
+                VideoTask.status.in_(
+                    [
+                        VideoStatus.SUBMITTED.value,
+                        VideoStatus.QUEUED.value,
+                        VideoStatus.PROCESSING.value,
+                    ]
+                ),
+                VideoTask.next_poll_at <= now,
+                VideoTask.poll_count < VideoTask.max_poll_count,
+            )
+            .order_by(VideoTask.next_poll_at.asc())
+            .limit(limit)
+            .all()
+        )
+        return [t.id for t in tasks]
+
+    def get_task(self, db: Session, task_id: str) -> VideoTask | None:
+        # SQLAlchemy 1.4+ API
+        return db.get(VideoTask, task_id)
+
+    # ==================== 分阶段处理方法（优化数据库连接占用）====================
+
+    async def prepare_poll_context(
+        self, db: Session, task: VideoTask
+    ) -> VideoPollContext | InternalVideoPollResult:
+        """
+        阶段 1：准备轮询上下文（短暂持有数据库连接）
+
+        Returns:
+            VideoPollContext: 成功时返回上下文
+            InternalVideoPollResult: 失败时返回错误结果
+        """
+        if not task.endpoint_id or not task.key_id:
+            return InternalVideoPollResult(
+                status=VideoStatus.FAILED,
+                error_code="missing_provider_info",
+                error_message="Task missing endpoint_id or key_id",
+            )
+
+        endpoint = self._get_endpoint(db, task.endpoint_id)
+        key = self._get_key(db, task.key_id)
+
+        if not key.api_key:
+            return InternalVideoPollResult(
+                status=VideoStatus.FAILED,
+                error_code="provider_config_error",
+                error_message="Provider key not properly configured",
+            )
+
+        try:
+            upstream_key = crypto_service.decrypt(key.api_key)
+        except Exception:
+            logger.warning("Failed to decrypt provider key for task %s", task.id)
+            return InternalVideoPollResult(
+                status=VideoStatus.FAILED,
+                error_code="decryption_error",
+                error_message="Failed to decrypt provider key",
+            )
+
+        provider_format = (task.provider_api_format or "").strip().lower()
+        if not provider_format:
+            provider_format = make_signature_key(
+                str(getattr(endpoint, "api_family", "")).strip().lower(),
+                str(getattr(endpoint, "endpoint_kind", "")).strip().lower(),
+            )
+
+        # 构建请求头
+        if provider_format.startswith("gemini:"):
+            auth_info = await get_provider_auth(endpoint, key)
+        else:
+            auth_info = None
+        headers = self._build_headers(provider_format, upstream_key, endpoint, auth_info)
+
+        return VideoPollContext(
+            task_id=task.id,
+            external_task_id=task.external_task_id or "",
+            provider_api_format=provider_format,
+            base_url=endpoint.base_url or "",
+            upstream_key=upstream_key,
+            headers=headers,
+            poll_count=task.poll_count,
+            retry_count=task.retry_count,
+            poll_interval_seconds=task.poll_interval_seconds,
+            max_poll_count=task.max_poll_count,
+            current_status=task.status,
+        )
+
+    async def poll_task_http(self, ctx: VideoPollContext) -> InternalVideoPollResult:
+        """
+        阶段 2：执行 HTTP 请求（不持有数据库连接）
+
+        Args:
+            ctx: 轮询上下文
+
+        Returns:
+            InternalVideoPollResult: 轮询结果
+        """
+        if not ctx.external_task_id:
+            return InternalVideoPollResult(
+                status=VideoStatus.FAILED,
+                error_code="missing_external_task_id",
+                error_message="Task missing external_task_id",
+            )
+
+        if ctx.provider_api_format.startswith("gemini:"):
+            return await self._poll_gemini_with_context(ctx)
+        return await self._poll_openai_with_context(ctx)
+
+    async def update_task_after_poll(
+        self,
+        task_id: str,
+        result: InternalVideoPollResult,
+        ctx: VideoPollContext | None,
+        redis_client: Any | None,
+        error_exception: Exception | None = None,
+    ) -> None:
+        """
+        阶段 3：更新数据库（获取新的数据库连接）
+
+        Args:
+            task_id: 任务 ID
+            result: 轮询结果
+            ctx: 轮询上下文（准备阶段就失败时为 None）
+            redis_client: Redis 客户端
+            error_exception: 如果 HTTP 请求失败，传入异常对象
+        """
+        with create_session() as db:
+            task = db.get(VideoTask, task_id)
+            if not task:
+                logger.warning("Task %s disappeared during poll update", task_id)
+                return
+
+            if error_exception is not None and ctx is not None:
+                # HTTP 请求失败（需要 ctx 来计算 backoff）
+                self._handle_poll_error(task, error_exception, ctx)
+            elif result.status == VideoStatus.COMPLETED:
+                task.status = VideoStatus.COMPLETED.value
+                task.video_url = result.video_url
+                task.video_expires_at = result.expires_at
+                task.completed_at = datetime.now(timezone.utc)
+                task.progress_percent = 100
+                if result.video_urls:
+                    task.video_urls = result.video_urls
+                self._attach_poll_raw_response(task, result)
+            elif result.status == VideoStatus.FAILED:
+                task.status = VideoStatus.FAILED.value
+                task.error_code = result.error_code
+                task.error_message = result.error_message
+                task.completed_at = datetime.now(timezone.utc)
+                self._attach_poll_raw_response(task, result)
+            else:
+                task.poll_count += 1
+                task.progress_percent = result.progress_percent
+                task.next_poll_at = datetime.now(timezone.utc) + timedelta(
+                    seconds=task.poll_interval_seconds
+                )
+
+            # 超时检查
+            task.updated_at = datetime.now(timezone.utc)
+            if task.poll_count >= task.max_poll_count and task.status not in [
+                VideoStatus.COMPLETED.value,
+                VideoStatus.FAILED.value,
+                VideoStatus.CANCELLED.value,
+            ]:
+                task.status = VideoStatus.FAILED.value
+                task.error_code = "poll_timeout"
+                task.error_message = f"Task timed out after {task.poll_count} polls"
+                task.completed_at = datetime.now(timezone.utc)
+
+            # 终态结算
+            if task.status in (VideoStatus.COMPLETED.value, VideoStatus.FAILED.value):
+                try:
+                    await TaskApplicationService(db, redis_client=redis_client).finalize_video_task(
+                        task
+                    )
+                except Exception as exc:
+                    logger.exception(
+                        "Failed to record video usage for task=%s: %s",
+                        task.id,
+                        sanitize_error_message(str(exc)),
+                    )
+
+            db.commit()
+
+    def _handle_poll_error(self, task: VideoTask, exc: Exception, ctx: VideoPollContext) -> None:
+        """处理轮询错误"""
+        task.poll_count += 1
+        error_msg = sanitize_error_message(str(exc))
+        logger.warning("Poll error for task %s: %s", task.id, error_msg)
+        task.progress_message = f"Poll error: {error_msg}"
+
+        status_code = exc.status_code if isinstance(exc, PollHTTPError) else None
+        is_permanent = self._is_permanent_error(exc, status_code=status_code)
+        if is_permanent:
+            task.status = VideoStatus.FAILED.value
+            task.error_code = "poll_permanent_error"
+            task.error_message = error_msg
+            task.completed_at = datetime.now(timezone.utc)
+        else:
+            backoff = min(
+                ctx.poll_interval_seconds * (2 ** min(ctx.retry_count, 5)),
+                self.max_backoff_seconds,
+            )
+            task.retry_count += 1
+            task.next_poll_at = datetime.now(timezone.utc) + timedelta(seconds=backoff)
+
+    async def _poll_openai_with_context(self, ctx: VideoPollContext) -> InternalVideoPollResult:
+        """使用上下文进行 OpenAI 轮询（不需要数据库）"""
+        url = self._build_openai_url(ctx.base_url, ctx.external_task_id)
+
+        client = await HTTPClientPool.get_default_client_async()
+        response = await client.get(url, headers=ctx.headers)
+        if response.status_code >= 400:
+            error_message = self._extract_error_message(response.text, response.status_code)
+            raise PollHTTPError(response.status_code, error_message)
+
+        payload = response.json()
+        return self._openai_normalizer.video_poll_to_internal(payload)
+
+    async def _poll_gemini_with_context(self, ctx: VideoPollContext) -> InternalVideoPollResult:
+        """使用上下文进行 Gemini 轮询（不需要数据库）"""
+        operation_name = normalize_gemini_operation_id(ctx.external_task_id)
+        url = self._build_gemini_url(ctx.base_url, operation_name)
+
+        logger.debug(
+            "[VideoPoller] Gemini poll: task=%s external_id=%s url=%s",
+            ctx.task_id,
+            ctx.external_task_id,
+            url,
+        )
+
+        client = await HTTPClientPool.get_default_client_async()
+        response = await client.get(url, headers=ctx.headers)
+        if response.status_code >= 400:
+            logger.warning(
+                "[VideoPoller] Gemini poll failed: task=%s status=%s response=%s",
+                ctx.task_id,
+                response.status_code,
+                response.text[:500] if response.text else "(empty)",
+            )
+            error_message = self._extract_error_message(response.text, response.status_code)
+            raise PollHTTPError(response.status_code, error_message)
+
+        payload = response.json()
+        return self._gemini_normalizer.video_poll_to_internal(payload)
+
+    # ==================== 旧版方法（保留兼容性）====================
+
+    async def poll_single_task(
+        self, db: Session, task: VideoTask, *, redis_client: Any | None
+    ) -> None:
+        """
+        旧版单任务轮询方法（保留向后兼容）
+
+        注意：此方法在 HTTP 请求期间持有数据库连接，建议使用分阶段方法。
+        """
+        try:
+            result = await self._poll_task_status(db, task)
+            if result.status == VideoStatus.COMPLETED:
+                task.status = VideoStatus.COMPLETED.value
+                task.video_url = result.video_url
+                task.video_expires_at = result.expires_at
+                task.completed_at = datetime.now(timezone.utc)
+                task.progress_percent = 100
+                if result.video_urls:
+                    task.video_urls = result.video_urls
+                self._attach_poll_raw_response(task, result)
+            elif result.status == VideoStatus.FAILED:
+                task.status = VideoStatus.FAILED.value
+                task.error_code = result.error_code
+                task.error_message = result.error_message
+                task.completed_at = datetime.now(timezone.utc)
+                self._attach_poll_raw_response(task, result)
+            else:
+                task.poll_count += 1
+                task.progress_percent = result.progress_percent
+                task.next_poll_at = datetime.now(timezone.utc) + timedelta(
+                    seconds=task.poll_interval_seconds
+                )
+        except Exception as exc:
+            task.poll_count += 1
+            error_msg = sanitize_error_message(str(exc))
+            logger.warning("Poll error for task %s: %s", task.id, error_msg)
+            task.progress_message = f"Poll error: {error_msg}"
+
+            status_code = exc.status_code if isinstance(exc, PollHTTPError) else None
+            is_permanent = self._is_permanent_error(exc, status_code=status_code)
+            if is_permanent:
+                task.status = VideoStatus.FAILED.value
+                task.error_code = "poll_permanent_error"
+                task.error_message = error_msg
+                task.completed_at = datetime.now(timezone.utc)
+            else:
+                backoff = min(
+                    task.poll_interval_seconds * (2 ** min(task.retry_count, 5)),
+                    self.max_backoff_seconds,
+                )
+                task.retry_count += 1
+                task.next_poll_at = datetime.now(timezone.utc) + timedelta(seconds=backoff)
+
+        # 超时：超过最大轮询次数且未进入终态
+        task.updated_at = datetime.now(timezone.utc)
+        if task.poll_count >= task.max_poll_count and task.status not in [
+            VideoStatus.COMPLETED.value,
+            VideoStatus.FAILED.value,
+            VideoStatus.CANCELLED.value,
+        ]:
+            task.status = VideoStatus.FAILED.value
+            task.error_code = "poll_timeout"
+            task.error_message = f"Task timed out after {task.poll_count} polls"
+            task.completed_at = datetime.now(timezone.utc)
+
+        # 终态结算
+        if task.status in (VideoStatus.COMPLETED.value, VideoStatus.FAILED.value):
+            try:
+                await TaskApplicationService(db, redis_client=redis_client).finalize_video_task(
+                    task
+                )
+            except Exception as exc:
+                logger.exception(
+                    "Failed to record video usage for task=%s: %s",
+                    task.id,
+                    sanitize_error_message(str(exc)),
+                )
+
+    def _attach_poll_raw_response(self, task: VideoTask, result: InternalVideoPollResult) -> None:
+        if not result.raw_response:
+            return
+        # 重新赋值整个字典，确保 SQLAlchemy 检测到变更
+        # （直接修改 JSON 字段内部不会自动标记为 dirty）
+        metadata = dict(task.request_metadata) if task.request_metadata else {}
+        metadata["poll_raw_response"] = result.raw_response
+        task.request_metadata = metadata
+
+    def _is_permanent_error(self, exc: Exception, status_code: int | None = None) -> bool:
+        if status_code is not None:
+            return 400 <= status_code < 500 and status_code != 429
+        error_msg = str(exc).lower()
+        return any(indicator in error_msg for indicator in _PERMANENT_ERROR_INDICATORS)
+
+    async def _poll_task_status(self, db: Session, task: VideoTask) -> InternalVideoPollResult:
+        if not task.endpoint_id or not task.key_id:
+            return InternalVideoPollResult(
+                status=VideoStatus.FAILED,
+                error_code="missing_provider_info",
+                error_message="Task missing endpoint_id or key_id",
+            )
+        endpoint = self._get_endpoint(db, task.endpoint_id)
+        key = self._get_key(db, task.key_id)
+        if not key.api_key:
+            return InternalVideoPollResult(
+                status=VideoStatus.FAILED,
+                error_code="provider_config_error",
+                error_message="Provider key not properly configured",
+            )
+        try:
+            upstream_key = crypto_service.decrypt(key.api_key)
+        except Exception:
+            logger.warning("Failed to decrypt provider key for task %s", task.id)
+            return InternalVideoPollResult(
+                status=VideoStatus.FAILED,
+                error_code="decryption_error",
+                error_message="Failed to decrypt provider key",
+            )
+
+        provider_format = (task.provider_api_format or "").strip().lower()
+        if not provider_format:
+            provider_format = make_signature_key(
+                str(getattr(endpoint, "api_family", "")).strip().lower(),
+                str(getattr(endpoint, "endpoint_kind", "")).strip().lower(),
+            )
+
+        if provider_format.startswith("gemini:"):
+            auth_info = await get_provider_auth(endpoint, key)
+            return await self._poll_gemini(task, endpoint, upstream_key, auth_info)
+        return await self._poll_openai(task, endpoint, upstream_key)
+
+    async def _poll_openai(
+        self,
+        task: VideoTask,
+        endpoint: ProviderEndpoint,
+        upstream_key: str,
+    ) -> InternalVideoPollResult:
+        if not task.external_task_id:
+            return InternalVideoPollResult(
+                status=VideoStatus.FAILED,
+                error_code="missing_external_task_id",
+                error_message="Task missing external_task_id",
+            )
+        url = self._build_openai_url(endpoint.base_url, task.external_task_id)
+        endpoint_sig = (task.provider_api_format or "").strip().lower() or make_signature_key(
+            str(getattr(endpoint, "api_family", "")).strip().lower(),
+            str(getattr(endpoint, "endpoint_kind", "")).strip().lower(),
+        )
+        headers = self._build_headers(endpoint_sig, upstream_key, endpoint)
+
+        client = await HTTPClientPool.get_default_client_async()
+        response = await client.get(url, headers=headers)
+        if response.status_code >= 400:
+            error_message = self._extract_error_message(response.text, response.status_code)
+            raise PollHTTPError(response.status_code, error_message)
+
+        payload = response.json()
+        return self._openai_normalizer.video_poll_to_internal(payload)
+
+    async def _poll_gemini(
+        self,
+        task: VideoTask,
+        endpoint: ProviderEndpoint,
+        upstream_key: str,
+        auth_info: ProviderAuthInfo | None,
+    ) -> InternalVideoPollResult:
+        if not task.external_task_id:
+            return InternalVideoPollResult(
+                status=VideoStatus.FAILED,
+                error_code="missing_external_task_id",
+                error_message="Task missing external_task_id",
+            )
+        operation_name = normalize_gemini_operation_id(task.external_task_id)
+        url = self._build_gemini_url(endpoint.base_url, operation_name)
+        endpoint_sig = (task.provider_api_format or "").strip().lower() or make_signature_key(
+            str(getattr(endpoint, "api_family", "")).strip().lower(),
+            str(getattr(endpoint, "endpoint_kind", "")).strip().lower(),
+        )
+        headers = self._build_headers(endpoint_sig, upstream_key, endpoint, auth_info)
+
+        logger.debug(
+            "[VideoPoller] Gemini poll: task=%s external_id=%s url=%s",
+            task.id,
+            task.external_task_id,
+            url,
+        )
+
+        client = await HTTPClientPool.get_default_client_async()
+        response = await client.get(url, headers=headers)
+        if response.status_code >= 400:
+            logger.warning(
+                "[VideoPoller] Gemini poll failed: task=%s status=%s response=%s",
+                task.id,
+                response.status_code,
+                response.text[:500] if response.text else "(empty)",
+            )
+            error_message = self._extract_error_message(response.text, response.status_code)
+            raise PollHTTPError(response.status_code, error_message)
+
+        payload = response.json()
+        return self._gemini_normalizer.video_poll_to_internal(payload)
+
+    def _build_openai_url(self, base_url: str | None, task_id: str) -> str:
+        base = (base_url or "https://api.openai.com").rstrip("/")
+        if base.endswith("/v1"):
+            return f"{base}/videos/{task_id}"
+        return f"{base}/v1/videos/{task_id}"
+
+    def _build_gemini_url(self, base_url: str | None, operation_name: str) -> str:
+        base = (base_url or "https://generativelanguage.googleapis.com").rstrip("/")
+        if base.endswith("/v1beta"):
+            base = base[: -len("/v1beta")]
+        return f"{base}/v1beta/{operation_name}"
+
+    def _build_headers(
+        self,
+        endpoint_sig: str,
+        upstream_key: str,
+        endpoint: ProviderEndpoint,
+        auth_info: ProviderAuthInfo | None = None,
+    ) -> dict[str, str]:
+        extra_headers = get_extra_headers_from_endpoint(endpoint)
+        headers = build_upstream_headers_for_endpoint(
+            {},
+            endpoint_sig,
+            upstream_key,
+            endpoint_headers=extra_headers,
+        )
+        if auth_info:
+            headers.pop("x-goog-api-key", None)
+            headers[auth_info.auth_header] = auth_info.auth_value
+        return headers
+
+    def _get_endpoint(self, db: Session, endpoint_id: str) -> ProviderEndpoint:
+        endpoint = db.query(ProviderEndpoint).filter(ProviderEndpoint.id == endpoint_id).first()
+        if not endpoint:
+            raise RuntimeError("Provider endpoint not found")
+        return endpoint
+
+    def _get_key(self, db: Session, key_id: str) -> ProviderAPIKey:
+        key = db.query(ProviderAPIKey).filter(ProviderAPIKey.id == key_id).first()
+        if not key:
+            raise RuntimeError("Provider key not found")
+        return key
+
+    def _extract_error_message(self, response_text: str | None, status_code: int) -> str:
+        """从响应中提取有意义的错误信息"""
+        if not response_text:
+            return f"Request failed with status {status_code}"
+
+        # 尝试解析 JSON 格式的错误
+        try:
+            data = json.loads(response_text)
+            # OpenAI 格式: {"error": {"message": "..."}}
+            if isinstance(data.get("error"), dict):
+                error_obj = data["error"]
+                message = error_obj.get("message") or error_obj.get("detail") or str(error_obj)
+                return sanitize_error_message(message)
+            # Gemini 格式: {"error": {"message": "...", "code": 404}}
+            if "message" in data:
+                return sanitize_error_message(data["message"])
+        except (json.JSONDecodeError, TypeError, KeyError):
+            pass
+
+        # 回退到原始文本（截断）
+        return sanitize_error_message(response_text[:500])

src/services/task/impl/video_telemetry.py

@@ -1,320 +0,0 @@
-"""
-VideoTelemetry（Phase3）
-
-将 Video 异步任务的“终态计费 + Usage 写入 + required 缺失告警”从 poller 中抽离出来，
-便于未来 Image/Audio 复用相同框架。
-"""
-
-from __future__ import annotations
-
-from datetime import datetime, timezone
-from typing import Any
-
-from sqlalchemy.orm import Session
-
-from src.api.handlers.base.video_handler_base import sanitize_error_message
-from src.config.settings import config
-from src.core.api_format.conversion.internal_video import VideoStatus
-from src.core.logger import logger
-from src.models.database import ApiKey, Provider, User, VideoTask
-from src.services.billing.dimension_collector_service import DimensionCollectorService
-from src.services.billing.formula_engine import BillingIncompleteError, FormulaEngine
-from src.services.billing.rule_service import BillingRuleService
-from src.services.usage.service import UsageService
-
-
-class VideoTelemetry:
-    def __init__(self, db: Session, *, redis_client: Any | None = None) -> None:
-        self.db = db
-        self.redis = redis_client
-        self._formula_engine = FormulaEngine()
-
-    async def record_terminal_usage(self, task: VideoTask) -> None:
-        """
-        为视频任务终态写入 Usage：
-        - COMPLETED: 使用 FormulaEngine 计算 cost（或 no_rule / incomplete -> cost=0）
-        - FAILED: cost=0
-
-        该方法可能会在 strict_mode 缺失 required 维度时将任务降级为 FAILED 并隐藏产物。
-        """
-        request_id = None
-        if isinstance(task.request_metadata, dict):
-            request_id = task.request_metadata.get("request_id")
-        request_id = request_id or task.id
-
-        # 计算异步任务总耗时（ms）
-        response_time_ms = None
-        if task.submitted_at and task.completed_at:
-            delta = task.completed_at - task.submitted_at
-            response_time_ms = int(delta.total_seconds() * 1000)
-
-        # 基础维度（无需 collectors 也可计费）
-        base_dimensions: dict[str, Any] = {
-            "duration_seconds": task.duration_seconds,
-            "resolution": task.resolution,
-            "aspect_ratio": task.aspect_ratio,
-            "size": task.size or "",
-            "retry_count": task.retry_count,
-        }
-
-        # collectors 可用的 metadata（结构稳定，便于配置 path）
-        collector_metadata: dict[str, Any] = {
-            "task": {
-                "id": task.id,
-                "external_task_id": task.external_task_id,
-                "model": task.model,
-                "duration_seconds": task.duration_seconds,
-                "resolution": task.resolution,
-                "aspect_ratio": task.aspect_ratio,
-                "size": task.size,
-                "retry_count": task.retry_count,
-                "video_size_bytes": task.video_size_bytes,
-            },
-            "result": {
-                "video_url": task.video_url,
-                "video_urls": task.video_urls or [],
-            },
-        }
-
-        # 维度采集：base + collectors 覆盖/补全
-        dims = DimensionCollectorService(self.db).collect_dimensions(
-            api_format=task.provider_api_format,
-            task_type="video",
-            request=task.original_request_body or {},
-            response=(
-                (task.request_metadata or {}).get("poll_raw_response")
-                if isinstance(task.request_metadata, dict)
-                else None
-            ),
-            metadata=collector_metadata,
-            base_dimensions=base_dimensions,
-        )
-
-        # 取冻结的 rule_snapshot；若缺失则回退 DB 查找（兼容旧任务）
-        rule_snapshot = None
-        if isinstance(task.request_metadata, dict):
-            rule_snapshot = task.request_metadata.get("billing_rule_snapshot")
-
-        billing_snapshot: dict[str, Any] = {
-            "status": "complete",
-            "missing_required": [],
-            "strict_mode": config.billing_strict_mode,
-        }
-        cost = 0.0
-
-        if task.status == VideoStatus.FAILED.value:
-            billing_snapshot["billed_reason"] = "task_failed"
-        else:
-            # COMPLETED：计算成本
-            expression = None
-            variables = None
-            dimension_mappings = None
-            rule_id = None
-            rule_name = None
-            rule_scope = None
-
-            if isinstance(rule_snapshot, dict) and rule_snapshot.get("status") == "ok":
-                rule_id = rule_snapshot.get("rule_id")
-                rule_name = rule_snapshot.get("rule_name")
-                rule_scope = rule_snapshot.get("scope")
-                expression = rule_snapshot.get("expression")
-                variables = rule_snapshot.get("variables")
-                dimension_mappings = rule_snapshot.get("dimension_mappings")
-            else:
-                lookup = BillingRuleService.find_rule(
-                    self.db,
-                    provider_id=task.provider_id,
-                    model_name=task.model,
-                    task_type="video",
-                )
-                if lookup:
-                    rule = lookup.rule
-                    rule_id = rule.id
-                    rule_name = rule.name
-                    rule_scope = lookup.scope
-                    expression = rule.expression
-                    variables = rule.variables
-                    dimension_mappings = rule.dimension_mappings
-
-            if not expression:
-                billing_snapshot["status"] = "no_rule"
-                billing_snapshot["cost_breakdown"] = {"total": 0.0}
-                logger.warning(
-                    "No billing rule for video task (request_id=%s, model=%s, provider_id=%s)",
-                    request_id,
-                    task.model,
-                    task.provider_id,
-                )
-            else:
-                billing_snapshot.update(
-                    {
-                        "rule_id": rule_id,
-                        "rule_name": rule_name,
-                        "rule_scope": rule_scope,
-                        "expression": expression,
-                        "variables": variables or {},
-                    }
-                )
-                try:
-                    result = self._formula_engine.evaluate(
-                        expression=expression,
-                        variables=variables or {},
-                        dimensions=dims,
-                        dimension_mappings=dimension_mappings or {},
-                        strict_mode=config.billing_strict_mode,
-                    )
-                    billing_snapshot["status"] = result.status
-                    billing_snapshot["missing_required"] = result.missing_required
-                    billing_snapshot["resolved_values"] = result.resolved_values
-                    if result.status == "complete":
-                        cost = result.cost
-                    else:
-                        logger.error(
-                            "Billing incomplete due to missing required dimensions "
-                            "(request_id=%s, model=%s, missing=%s)",
-                            request_id,
-                            task.model,
-                            result.missing_required,
-                        )
-                        cost = 0.0
-                        await self._maybe_alert_missing_required(
-                            model=task.model,
-                            missing_required=result.missing_required,
-                        )
-                    if result.error:
-                        billing_snapshot["error"] = result.error
-                except BillingIncompleteError as exc:
-                    logger.error(
-                        "Billing strict mode triggered (request_id=%s, model=%s, missing=%s)",
-                        request_id,
-                        task.model,
-                        exc.missing_required,
-                    )
-                    billing_snapshot["status"] = "incomplete"
-                    billing_snapshot["missing_required"] = exc.missing_required
-                    billing_snapshot["resolved_values"] = {}
-                    billing_snapshot["error"] = "strict_mode_missing_required"
-                    cost = 0.0
-
-                    # strict_mode=true：标记任务失败并隐藏产物，避免"免费放行"
-                    task.status = VideoStatus.FAILED.value
-                    task.error_code = "billing_incomplete"
-                    task.error_message = f"Missing required dimensions: {exc.missing_required}"
-                    task.video_url = None
-                    task.video_urls = None
-
-                    await self._maybe_alert_missing_required(
-                        model=task.model,
-                        missing_required=exc.missing_required,
-                    )
-
-                billing_snapshot["cost_breakdown"] = {"total": cost}
-
-        # 将 billing_snapshot 回写到 task.request_metadata 便于对账（不会影响 usage 的单独存档）
-        if task.request_metadata is None:
-            task.request_metadata = {}
-        if isinstance(task.request_metadata, dict):
-            task.request_metadata["billing_snapshot"] = billing_snapshot
-
-        usage_metadata: dict[str, Any] = {
-            "billing_snapshot": billing_snapshot,
-            "dimensions": dims,
-            "raw_response_ref": {
-                "video_task_id": task.id,
-                "field": "video_tasks.request_metadata.poll_raw_response",
-            },
-        }
-
-        # 查询关联对象（用于写入 usage.user_id/api_key_id 等）
-        user_obj = self.db.query(User).filter(User.id == task.user_id).first()
-        api_key_obj = (
-            self.db.query(ApiKey).filter(ApiKey.id == task.api_key_id).first()
-            if task.api_key_id
-            else None
-        )
-        provider_obj = (
-            self.db.query(Provider).filter(Provider.id == task.provider_id).first()
-            if task.provider_id
-            else None
-        )
-        provider_name = provider_obj.name if provider_obj else "unknown"
-
-        await UsageService.record_usage_with_custom_cost(
-            db=self.db,
-            user=user_obj,
-            api_key=api_key_obj,
-            provider=provider_name,
-            model=task.model,
-            request_type="video",
-            total_cost_usd=cost,
-            request_cost_usd=cost,
-            input_tokens=0,
-            output_tokens=0,
-            cache_creation_input_tokens=0,
-            cache_read_input_tokens=0,
-            api_format=task.client_api_format,
-            endpoint_api_format=task.provider_api_format,
-            has_format_conversion=bool(task.format_converted),
-            is_stream=False,
-            response_time_ms=response_time_ms,
-            first_byte_time_ms=None,
-            status_code=200 if task.status == VideoStatus.COMPLETED.value else 500,
-            error_message=(
-                None
-                if task.status == VideoStatus.COMPLETED.value
-                else (task.error_message or task.error_code or "video_task_failed")
-            ),
-            metadata=usage_metadata,
-            request_headers=(
-                (task.request_metadata or {}).get("request_headers")
-                if isinstance(task.request_metadata, dict)
-                else None
-            ),
-            request_body=task.original_request_body,
-            provider_request_headers=None,
-            response_headers=None,
-            client_response_headers=None,
-            response_body=None,
-            request_id=request_id,
-            provider_id=task.provider_id,
-            provider_endpoint_id=task.endpoint_id,
-            provider_api_key_id=task.key_id,
-            status="completed" if task.status == VideoStatus.COMPLETED.value else "failed",
-            target_model=None,
-        )
-
-    async def _maybe_alert_missing_required(
-        self, *, model: str, missing_required: list[str]
-    ) -> None:
-        """required 维度缺失告警：同一 (model, dimension) 1 小时内 >= 10 次触发升级告警。"""
-        if not missing_required:
-            return
-        if not self.redis:
-            logger.error(
-                "Missing required billing dimensions (model=%s): %s", model, missing_required
-            )
-            return
-
-        # 按小时 bucket 聚合
-        now = datetime.now(timezone.utc)
-        hour_bucket = now.strftime("%Y%m%d%H")
-        for dim in missing_required:
-            key = f"billing:missing_required:{model}:{dim}:{hour_bucket}"
-            try:
-                count = await self.redis.incr(key)
-                if count == 1:
-                    await self.redis.expire(key, 3700)
-                if count >= 10:
-                    logger.warning(
-                        "Billing required dimension missing frequently (model=%s, dim=%s, count=%s/hour)",
-                        model,
-                        dim,
-                        count,
-                    )
-            except Exception as exc:
-                logger.warning(
-                    "Failed to record billing alert counter: %s", sanitize_error_message(str(exc))
-                )
-
-
-__all__ = ["VideoTelemetry"]

src/services/task/lifecycle.py

@@ -0,0 +1,27 @@
+from __future__ import annotations
+
+from enum import Enum
+
+
+class TaskStatus(str, Enum):
+    """Generic task status (progress)."""
+
+    PENDING = "pending"
+    STREAMING = "streaming"
+
+    SUBMITTED = "submitted"
+    QUEUED = "queued"
+    PROCESSING = "processing"
+
+    COMPLETED = "completed"
+    FAILED = "failed"
+    CANCELLED = "cancelled"
+    EXPIRED = "expired"
+
+
+class BillingStatus(str, Enum):
+    """Billing settlement status (Usage.billing_status)."""
+
+    PENDING = "pending"
+    SETTLED = "settled"
+    VOID = "void"

src/services/task/orchestrator.py

@@ -1,635 +0,0 @@
-"""
-AsyncTaskOrchestrator
-
-提交阶段故障转移（多候选尝试）：
-- 目标：拿到 external_task_id 后锁定 provider/endpoint/key，后续轮询不再切换。
-- 仅覆盖“提交阶段”；轮询阶段由各 task poller 使用已锁定的信息执行。
-"""
-
-from __future__ import annotations
-
-import re
-import uuid
-from dataclasses import dataclass
-from datetime import datetime, timezone
-from typing import Any, Protocol, runtime_checkable
-
-import httpx
-from redis.asyncio import Redis
-from sqlalchemy.orm import Session
-
-from src.config.settings import config
-from src.core.exceptions import ProviderNotAvailableException
-from src.core.logger import logger
-from src.models.database import ApiKey, RequestCandidate
-from src.services.billing.rule_service import BillingRuleLookupResult, BillingRuleService
-from src.services.cache.aware_scheduler import ProviderCandidate, get_cache_aware_scheduler
-from src.services.orchestration.candidate_resolver import CandidateResolver
-from src.services.orchestration.error_classifier import ErrorClassifier
-from src.services.system.config import SystemConfigService
-
-_SENSITIVE_PATTERN = re.compile(
-    r"(api[_-]?key|token|bearer|authorization)[=:\s]+\S+",
-    re.IGNORECASE,
-)
-
-
-def _sanitize(message: str, max_length: int = 200) -> str:
-    if not message:
-        return "request_failed"
-    return _SENSITIVE_PATTERN.sub("[REDACTED]", message)[:max_length]
-
-
-@runtime_checkable
-class SubmitFunc(Protocol):
-    async def __call__(self, candidate: ProviderCandidate) -> httpx.Response: ...
-
-
-@runtime_checkable
-class ExtractExternalTaskIdFunc(Protocol):
-    def __call__(self, payload: dict[str, Any]) -> str | None: ...
-
-
-class UpstreamClientRequestError(RuntimeError):
-    """可判定为客户端请求问题（不应 failover）的上游错误。"""
-
-    def __init__(
-        self,
-        *,
-        response: httpx.Response,
-        candidate_keys: list[dict[str, Any]],
-    ) -> None:
-        self.response = response
-        self.candidate_keys = candidate_keys
-        super().__init__(f"Upstream client error: HTTP {response.status_code}")
-
-
-class AllCandidatesFailedError(RuntimeError):
-    def __init__(
-        self,
-        *,
-        reason: str,
-        candidate_keys: list[dict[str, Any]],
-        last_status_code: int | None = None,
-    ) -> None:
-        self.reason = reason
-        self.candidate_keys = candidate_keys
-        self.last_status_code = last_status_code
-        super().__init__(f"All candidates failed: {reason}")
-
-
-class CandidateUnsupportedError(RuntimeError):
-    """候选不被当前任务支持（如 auth_type/格式转换需求不支持）。"""
-
-
-class CandidateSubmissionError(RuntimeError):
-    """候选提交异常（网络/解密/解析等）。"""
-
-
-@dataclass(slots=True)
-class SubmitOutcome:
-    candidate: ProviderCandidate
-    candidate_keys: list[dict[str, Any]]
-    external_task_id: str
-    rule_lookup: BillingRuleLookupResult | None
-    upstream_payload: dict[str, Any] | None = None
-
-
-class AsyncTaskOrchestrator:
-    """
-    异步任务编排器：只负责提交阶段的候选遍历与错误处理策略。
-    """
-
-    def __init__(self, db: Session, *, redis_client: Redis | None = None) -> None:
-        self.db = db
-        self.redis = redis_client
-        self._candidate_resolver: CandidateResolver | None = None
-        self._error_classifier: ErrorClassifier | None = None
-
-        self._cache_scheduler = None
-        # 候选记录映射：{candidate_index: RequestCandidate}
-        self._candidate_records: dict[int, RequestCandidate] = {}
-
-    def _create_candidate_records(
-        self,
-        candidates: list[ProviderCandidate],
-        request_id: str | None,
-        user_api_key: ApiKey,
-    ) -> dict[int, RequestCandidate]:
-        """
-        为所有候选预创建 RequestCandidate 记录。
-
-        Args:
-            candidates: 候选列表
-            request_id: 请求 ID
-            user_api_key: 用户 API Key
-
-        Returns:
-            {candidate_index: RequestCandidate} 映射
-        """
-        if not request_id:
-            return {}
-
-        now = datetime.now(timezone.utc)
-        records: dict[int, RequestCandidate] = {}
-
-        for idx, cand in enumerate(candidates):
-            record = RequestCandidate(
-                id=str(uuid.uuid4()),
-                request_id=request_id,
-                candidate_index=idx,
-                retry_index=0,
-                user_id=user_api_key.user_id if user_api_key else None,
-                api_key_id=user_api_key.id if user_api_key else None,
-                provider_id=cand.provider.id,
-                endpoint_id=cand.endpoint.id,
-                key_id=cand.key.id,
-                status="available",
-                is_cached=bool(getattr(cand, "is_cached", False)),
-                created_at=now,
-            )
-            self.db.add(record)
-            records[idx] = record
-
-        try:
-            self.db.flush()
-        except Exception as exc:
-            logger.warning(
-                "[AsyncTaskOrchestrator] Failed to create candidate records: %s",
-                str(exc),
-            )
-            self.db.rollback()
-            return {}
-
-        return records
-
-    def _update_candidate_record(
-        self,
-        idx: int,
-        *,
-        status: str,
-        skip_reason: str | None = None,
-        status_code: int | None = None,
-        error_type: str | None = None,
-        error_message: str | None = None,
-        started_at: datetime | None = None,
-        finished_at: datetime | None = None,
-    ) -> None:
-        """更新候选记录状态。"""
-        record = self._candidate_records.get(idx)
-        if not record:
-            return
-
-        record.status = status
-        if skip_reason is not None:
-            record.skip_reason = skip_reason
-        if status_code is not None:
-            record.status_code = status_code
-        if error_type is not None:
-            record.error_type = error_type
-        if error_message is not None:
-            record.error_message = error_message
-        if started_at is not None:
-            record.started_at = started_at
-        if finished_at is not None:
-            record.finished_at = finished_at
-
-        try:
-            self.db.flush()
-        except Exception as exc:
-            logger.warning(
-                "[AsyncTaskOrchestrator] Failed to update candidate record %d: %s",
-                idx,
-                str(exc),
-            )
-
-    def _commit_candidate_records(self) -> None:
-        """提交候选记录到数据库。"""
-        if not self._candidate_records:
-            return
-        try:
-            self.db.commit()
-        except Exception as exc:
-            logger.warning(
-                "[AsyncTaskOrchestrator] Failed to commit candidate records: %s",
-                str(exc),
-            )
-            self.db.rollback()
-
-    async def _ensure_initialized(self) -> None:
-        if self._cache_scheduler is not None:
-            return
-
-        # 使用 SystemConfigService 读取运行时调度策略（与 Chat/CLI 一致）
-        priority_mode = SystemConfigService.get_config(
-            self.db,
-            "provider_priority_mode",
-            "provider",
-        )
-        scheduling_mode = SystemConfigService.get_config(
-            self.db,
-            "scheduling_mode",
-            "cache_affinity",
-        )
-        self._cache_scheduler = await get_cache_aware_scheduler(
-            self.redis,
-            priority_mode=priority_mode,
-            scheduling_mode=scheduling_mode,
-        )
-
-        self._candidate_resolver = CandidateResolver(
-            db=self.db,
-            cache_scheduler=self._cache_scheduler,
-        )
-        self._error_classifier = ErrorClassifier(db=self.db, cache_scheduler=self._cache_scheduler)
-
-    def _should_stop_on_http_error(self, *, status_code: int, error_text: str) -> bool:
-        """
-        判断某个上游 HTTP 错误是否为“客户端错误”（不应 failover）。
-
-        规则：
-        - 401/403/429：一般是 key/权限/限流问题，优先 failover
-        - 其他 4xx：若 ErrorClassifier 判断为客户端请求错误，则停止
-        """
-        if status_code in (401, 403, 429):
-            return False
-        if 400 <= status_code < 500:
-            assert self._error_classifier is not None
-            return self._error_classifier.is_client_error(error_text)
-        return False
-
-    async def submit_with_failover(
-        self,
-        *,
-        api_format: str,
-        model_name: str,
-        affinity_key: str,
-        user_api_key: ApiKey,
-        request_id: str | None,
-        task_type: str,
-        submit_func: SubmitFunc,
-        extract_external_task_id: ExtractExternalTaskIdFunc,
-        supported_auth_types: set[str] | None = None,
-        allow_format_conversion: bool = False,
-        capability_requirements: dict[str, bool] | None = None,
-        max_candidates: int | None = None,
-    ) -> SubmitOutcome:
-        """
-        提交异步任务并在失败时自动尝试下一个候选，直到拿到 external_task_id。
-
-        Returns:
-            SubmitOutcome（包含选中的候选 + external_task_id + candidate_keys + billing rule lookup）
-
-        Raises:
-            UpstreamClientRequestError: 判定为客户端请求错误（不应 failover）
-            ProviderNotAvailableException: 没有可用候选（调度器层面）
-            AllCandidatesFailedError: 有候选但全部提交失败
-        """
-        await self._ensure_initialized()
-        assert self._candidate_resolver is not None
-
-        logger.info(
-            "[AsyncTaskOrchestrator] submit_with_failover: "
-            "api_format=%s, model=%s, task_type=%s, request_id=%s",
-            api_format,
-            model_name,
-            task_type,
-            request_id,
-        )
-
-        candidates, _global_model_id = await self._candidate_resolver.fetch_candidates(
-            api_format=api_format,
-            model_name=model_name,
-            affinity_key=affinity_key,
-            user_api_key=user_api_key,
-            request_id=request_id,
-            is_stream=False,
-            capability_requirements=capability_requirements,
-        )
-
-        logger.info(
-            "[AsyncTaskOrchestrator] fetch_candidates returned %d candidates for model=%s",
-            len(candidates),
-            model_name,
-        )
-
-        # 如果没有候选，直接抛出异常
-        if not candidates:
-            logger.error(
-                "[AsyncTaskOrchestrator] No candidates returned from fetch_candidates for model=%s",
-                model_name,
-            )
-            raise ProviderNotAvailableException("No candidates available")
-
-        if max_candidates is not None and max_candidates > 0:
-            candidates = candidates[:max_candidates]
-
-        # 创建候选记录（用于链路追踪）
-        self._candidate_records = self._create_candidate_records(
-            candidates=candidates,
-            request_id=request_id,
-            user_api_key=user_api_key,
-        )
-
-        candidate_keys: list[dict[str, Any]] = []
-        eligible_count = 0
-        last_status_code: int | None = None
-
-        for idx, cand in enumerate(candidates):
-            submit_started_at = datetime.now(timezone.utc)
-            auth_type = getattr(cand.key, "auth_type", "api_key") or "api_key"
-            candidate_info: dict[str, Any] = {
-                "index": idx,
-                "provider_id": cand.provider.id,
-                "provider_name": cand.provider.name,
-                "endpoint_id": cand.endpoint.id,
-                "key_id": cand.key.id,
-                "key_name": cand.key.name,
-                "auth_type": auth_type,
-                "priority": getattr(cand.key, "priority", 0) or 0,
-                "is_cached": bool(getattr(cand, "is_cached", False)),
-            }
-            candidate_keys.append(candidate_info)
-
-            logger.info(
-                "[AsyncTaskOrchestrator] Checking candidate %d: provider=%s, is_skipped=%s, skip_reason=%s, needs_conversion=%s, auth_type=%s",
-                idx,
-                cand.provider.name,
-                getattr(cand, "is_skipped", False),
-                getattr(cand, "skip_reason", None),
-                getattr(cand, "needs_conversion", False),
-                auth_type,
-            )
-
-            # 调度器层面标记为跳过（健康/熔断/并发等）
-            if getattr(cand, "is_skipped", False):
-                skip_reason = getattr(cand, "skip_reason", None) or "skipped"
-                candidate_info.update(
-                    {
-                        "skipped": True,
-                        "skip_reason": skip_reason,
-                    }
-                )
-                self._update_candidate_record(idx, status="skipped", skip_reason=skip_reason)
-                logger.info(
-                    "[AsyncTaskOrchestrator] Candidate %d skipped: is_skipped=True, reason=%s",
-                    idx,
-                    cand.skip_reason,
-                )
-                continue
-
-            # 视频/图片等直连 upstream 的 handler 目前不支持跨格式转换
-            if not allow_format_conversion and bool(getattr(cand, "needs_conversion", False)):
-                candidate_info.update(
-                    {"skipped": True, "skip_reason": "format_conversion_not_supported"}
-                )
-                self._update_candidate_record(
-                    idx, status="skipped", skip_reason="format_conversion_not_supported"
-                )
-                logger.info("[AsyncTaskOrchestrator] Candidate %d skipped: needs_conversion", idx)
-                continue
-
-            # auth_type 过滤
-            if supported_auth_types is not None and auth_type not in supported_auth_types:
-                skip_reason = f"unsupported_auth_type:{auth_type}"
-                candidate_info.update(
-                    {
-                        "skipped": True,
-                        "skip_reason": skip_reason,
-                    }
-                )
-                self._update_candidate_record(idx, status="skipped", skip_reason=skip_reason)
-                logger.info(
-                    "[AsyncTaskOrchestrator] Candidate %d skipped: unsupported_auth_type=%s",
-                    idx,
-                    auth_type,
-                )
-                continue
-
-            # billing rule 过滤（可选）
-            rule_lookup: BillingRuleLookupResult | None = None
-            has_billing_rule = True
-            if config.billing_require_rule:
-                logger.info(
-                    "[AsyncTaskOrchestrator] Checking billing rule for candidate %d (billing_require_rule=True)",
-                    idx,
-                )
-                rule_lookup = BillingRuleService.find_rule(
-                    self.db,
-                    provider_id=cand.provider.id,
-                    model_name=model_name,
-                    task_type=task_type,
-                )
-                has_billing_rule = rule_lookup is not None
-                logger.info(
-                    "[AsyncTaskOrchestrator] Billing rule lookup result: has_rule=%s",
-                    has_billing_rule,
-                )
-                if not has_billing_rule:
-                    candidate_info.update(
-                        {
-                            "has_billing_rule": False,
-                            "skipped": True,
-                            "skip_reason": "billing_rule_missing",
-                        }
-                    )
-                    self._update_candidate_record(
-                        idx, status="skipped", skip_reason="billing_rule_missing"
-                    )
-                    logger.info(
-                        "[AsyncTaskOrchestrator] Candidate %d skipped: billing_rule_missing", idx
-                    )
-                    continue
-            candidate_info["has_billing_rule"] = has_billing_rule
-
-            logger.info("[AsyncTaskOrchestrator] Candidate %d eligible, attempting submit", idx)
-            eligible_count += 1
-
-            # 更新记录为 pending 状态（开始尝试）
-            self._update_candidate_record(idx, status="pending", started_at=submit_started_at)
-
-            # 尝试提交
-            try:
-                response = await submit_func(cand)
-            except Exception as exc:
-                finished_at = datetime.now(timezone.utc)
-                logger.error(
-                    "[AsyncTaskOrchestrator] Candidate %d submit exception: %s: %s",
-                    idx,
-                    type(exc).__name__,
-                    str(exc),
-                )
-                error_msg = _sanitize(str(exc))
-                candidate_info.update(
-                    {
-                        "attempt_status": "exception",
-                        "error_type": type(exc).__name__,
-                        "error_message": error_msg,
-                    }
-                )
-                self._update_candidate_record(
-                    idx,
-                    status="failed",
-                    error_type=type(exc).__name__,
-                    error_message=error_msg,
-                    finished_at=finished_at,
-                )
-                continue
-
-            logger.info(
-                "[AsyncTaskOrchestrator] Candidate %d submit response: status_code=%d",
-                idx,
-                response.status_code,
-            )
-
-            last_status_code = int(getattr(response, "status_code", 0) or 0)
-
-            # 上游错误：决定是否停止
-            if response.status_code >= 400:
-                finished_at = datetime.now(timezone.utc)
-                error_text = ""
-                try:
-                    error_text = response.text or ""
-                except Exception:
-                    error_text = ""
-                error_msg = _sanitize(error_text)
-                candidate_info.update(
-                    {
-                        "attempt_status": "http_error",
-                        "status_code": response.status_code,
-                        "error_message": error_msg,
-                    }
-                )
-                self._update_candidate_record(
-                    idx,
-                    status="failed",
-                    status_code=response.status_code,
-                    error_type="http_error",
-                    error_message=error_msg,
-                    finished_at=finished_at,
-                )
-                if self._should_stop_on_http_error(
-                    status_code=response.status_code, error_text=error_text
-                ):
-                    self._commit_candidate_records()
-                    raise UpstreamClientRequestError(
-                        response=response,
-                        candidate_keys=candidate_keys,
-                    )
-                continue
-
-            # 解析任务 ID（200 但缺字段也视为失败并 failover）
-            payload: dict[str, Any] | None = None
-            try:
-                data = response.json()
-                if isinstance(data, dict):
-                    payload = data
-                logger.info(
-                    "[AsyncTaskOrchestrator] Candidate %d response payload: %s",
-                    idx,
-                    str(payload)[:500] if payload else "None",
-                )
-            except Exception as exc:
-                finished_at = datetime.now(timezone.utc)
-                logger.error(
-                    "[AsyncTaskOrchestrator] Candidate %d invalid JSON: %s",
-                    idx,
-                    str(exc),
-                )
-                error_msg = _sanitize(str(exc))
-                candidate_info.update(
-                    {
-                        "attempt_status": "invalid_json",
-                        "error_type": type(exc).__name__,
-                        "error_message": error_msg,
-                    }
-                )
-                self._update_candidate_record(
-                    idx,
-                    status="failed",
-                    status_code=response.status_code,
-                    error_type="invalid_json",
-                    error_message=error_msg,
-                    finished_at=finished_at,
-                )
-                continue
-
-            external_task_id = extract_external_task_id(payload or {})
-            logger.info(
-                "[AsyncTaskOrchestrator] Candidate %d extracted task_id: %s",
-                idx,
-                external_task_id,
-            )
-            if not external_task_id:
-                finished_at = datetime.now(timezone.utc)
-                candidate_info.update(
-                    {
-                        "attempt_status": "empty_task_id",
-                        "error_message": "Upstream returned empty task id",
-                    }
-                )
-                self._update_candidate_record(
-                    idx,
-                    status="failed",
-                    status_code=response.status_code,
-                    error_type="empty_task_id",
-                    error_message="Upstream returned empty task id",
-                    finished_at=finished_at,
-                )
-                logger.warning(
-                    "[AsyncTaskOrchestrator] Candidate %d: empty task_id, payload keys: %s",
-                    idx,
-                    list(payload.keys()) if payload else [],
-                )
-                continue
-
-            # 成功
-            finished_at = datetime.now(timezone.utc)
-            candidate_info.update({"attempt_status": "success", "selected": True})
-            self._update_candidate_record(
-                idx,
-                status="success",
-                status_code=response.status_code,
-                finished_at=finished_at,
-            )
-            self._commit_candidate_records()
-            return SubmitOutcome(
-                candidate=cand,
-                candidate_keys=candidate_keys,
-                external_task_id=str(external_task_id),
-                rule_lookup=rule_lookup,
-                upstream_payload=payload,
-            )
-
-        # 没有任何候选可尝试
-        if not candidates:
-            raise ProviderNotAvailableException("No candidates available")
-
-        # 提交所有候选记录
-        self._commit_candidate_records()
-
-        if eligible_count == 0:
-            reason = "no_eligible_candidates"
-            if config.billing_require_rule:
-                reason = "no_candidate_with_billing_rule"
-            raise AllCandidatesFailedError(
-                reason=reason,
-                candidate_keys=candidate_keys,
-                last_status_code=last_status_code,
-            )
-
-        raise AllCandidatesFailedError(
-            reason="all_candidates_failed",
-            candidate_keys=candidate_keys,
-            last_status_code=last_status_code,
-        )
-
-
-__all__ = [
-    "AsyncTaskOrchestrator",
-    "SubmitOutcome",
-    "AllCandidatesFailedError",
-    "UpstreamClientRequestError",
-    "CandidateUnsupportedError",
-    "CandidateSubmissionError",
-]

src/services/task/task_poller.py

@@ -0,0 +1,240 @@
+"""
+Task poller (Phase2)
+
+Provides a generic polling skeleton for async tasks.
+Currently wired with a video poller adapter.
+
+优化：HTTP 请求期间不持有数据库连接，避免阻塞其他请求。
+采用三阶段处理：准备数据 -> HTTP 请求 -> 更新数据库。
+"""
+
+from __future__ import annotations
+
+import asyncio
+from datetime import datetime, timezone
+from typing import Any, Protocol, runtime_checkable
+from uuid import uuid4
+
+from sqlalchemy.orm import Session
+
+from src.core.api_format.conversion.internal_video import InternalVideoPollResult
+from src.core.logger import logger
+from src.database import create_session
+from src.services.system.scheduler import get_scheduler
+from src.services.task.impl.video_poller import VideoPollContext, VideoTaskPollerAdapter
+
+
+@runtime_checkable
+class TaskPollerAdapter(Protocol):
+    task_type: str
+
+    # scheduler
+    job_id: str
+    job_name: str
+    interval_seconds: int
+
+    # distributed lock (optional, best-effort)
+    lock_key: str
+    lock_ttl: int
+
+    # execution
+    batch_size: int
+    concurrency: int
+    consecutive_failure_alert_threshold: int
+
+    def list_due_task_ids(self, db: Session, *, now: datetime, limit: int) -> list[str]: ...
+
+    def get_task(self, db: Session, task_id: str) -> Any | None: ...
+
+    # 分阶段处理方法（推荐使用）
+    async def prepare_poll_context(
+        self, db: Session, task: Any
+    ) -> Any: ...  # Returns context or error result
+
+    async def poll_task_http(self, ctx: Any) -> Any: ...  # Returns poll result
+
+    async def update_task_after_poll(
+        self,
+        task_id: str,
+        result: Any,
+        ctx: Any,
+        redis_client: Any | None,
+        error_exception: Exception | None = None,
+    ) -> None: ...
+
+    # 旧版方法（保留兼容性）
+    async def poll_single_task(
+        self, db: Session, task: Any, *, redis_client: Any | None
+    ) -> None: ...
+
+    def sanitize_error_message(self, message: str) -> str: ...
+
+
+class TaskPollerService:
+    """Generic background poller for async tasks."""
+
+    def __init__(self, adapter: TaskPollerAdapter) -> None:
+        self.adapter = adapter
+        self._lock = asyncio.Lock()
+        self.redis: Any | None = None
+        self._semaphore: asyncio.Semaphore | None = None
+        self._consecutive_failures = 0
+
+    async def start(self) -> None:
+        if self._semaphore is None:
+            self._semaphore = asyncio.Semaphore(self.adapter.concurrency)
+
+        # lazy import to avoid redis hard dependency in local runs
+        from src.clients.redis_client import get_redis_client
+
+        if self.redis is None:
+            self.redis = await get_redis_client(require_redis=False)
+
+        scheduler = get_scheduler()
+        scheduler.add_interval_job(
+            self.poll_pending_tasks,
+            seconds=self.adapter.interval_seconds,
+            job_id=self.adapter.job_id,
+            name=self.adapter.job_name,
+        )
+
+    async def stop(self) -> None:
+        scheduler = get_scheduler()
+        scheduler.remove_job(self.adapter.job_id)
+
+    async def poll_pending_tasks(self) -> None:
+        async with self._lock:
+            token = await self._acquire_redis_lock()
+            if token is None:
+                return
+
+            try:
+                with create_session() as db:
+                    now = datetime.now(timezone.utc)
+                    task_ids = self.adapter.list_due_task_ids(
+                        db, now=now, limit=self.adapter.batch_size
+                    )
+
+                if not task_ids:
+                    self._consecutive_failures = 0
+                    return
+
+                poll_results: list[bool] = []
+
+                if self._semaphore is None:
+                    self._semaphore = asyncio.Semaphore(self.adapter.concurrency)
+                semaphore = self._semaphore
+
+                async def poll_with_semaphore(task_id: str) -> None:
+                    async with semaphore:
+                        try:
+                            # ========== 阶段 1：准备数据（短暂持有连接）==========
+                            with create_session() as task_db:
+                                task_obj = self.adapter.get_task(task_db, task_id)
+                                if not task_obj:
+                                    logger.warning(
+                                        "[%s] Task %s disappeared during poll",
+                                        self.adapter.task_type,
+                                        task_id,
+                                    )
+                                    poll_results.append(True)
+                                    return
+
+                                ctx_or_result = await self.adapter.prepare_poll_context(
+                                    task_db, task_obj
+                                )
+
+                            # 检查是否是错误结果（而非上下文）
+                            if isinstance(ctx_or_result, InternalVideoPollResult):
+                                # 准备阶段就失败了，直接更新任务状态
+                                await self.adapter.update_task_after_poll(
+                                    task_id=task_id,
+                                    result=ctx_or_result,
+                                    ctx=None,  # type: ignore[arg-type]
+                                    redis_client=self.redis,
+                                )
+                                poll_results.append(True)
+                                return
+
+                            ctx: VideoPollContext = ctx_or_result
+
+                            # ========== 阶段 2：HTTP 请求（不持有数据库连接）==========
+                            error_exception: Exception | None = None
+                            try:
+                                result = await self.adapter.poll_task_http(ctx)
+                            except Exception as http_exc:
+                                # HTTP 请求失败，记录异常以便后续处理
+                                error_exception = http_exc
+                                result = InternalVideoPollResult(
+                                    status=None,  # type: ignore[arg-type]
+                                    error_message=str(http_exc),
+                                )
+
+                            # ========== 阶段 3：更新数据库（获取新连接）==========
+                            await self.adapter.update_task_after_poll(
+                                task_id=task_id,
+                                result=result,
+                                ctx=ctx,
+                                redis_client=self.redis,
+                                error_exception=error_exception,
+                            )
+                            poll_results.append(True)
+                        except Exception as exc:
+                            logger.exception(
+                                "[%s] Unexpected error polling task %s: %s",
+                                self.adapter.task_type,
+                                task_id,
+                                self.adapter.sanitize_error_message(str(exc)),
+                            )
+                            poll_results.append(False)
+
+                async with asyncio.TaskGroup() as tg:
+                    for tid in task_ids:
+                        tg.create_task(poll_with_semaphore(tid))
+
+                batch_failures = sum(1 for r in poll_results if r is False)
+                if batch_failures == len(task_ids):
+                    self._consecutive_failures += 1
+                    if (
+                        self._consecutive_failures
+                        >= self.adapter.consecutive_failure_alert_threshold
+                    ):
+                        logger.error(
+                            "[ALERT] %s poller: %d consecutive batches failed.",
+                            self.adapter.task_type,
+                            self._consecutive_failures,
+                        )
+                else:
+                    self._consecutive_failures = 0
+            finally:
+                await self._release_redis_lock(token)
+
+    async def _acquire_redis_lock(self) -> str | None:
+        if not self.redis:
+            return "no_redis"
+        token = str(uuid4())
+        acquired = await self.redis.set(
+            self.adapter.lock_key, token, nx=True, ex=self.adapter.lock_ttl
+        )
+        return token if acquired else None
+
+    async def _release_redis_lock(self, token: str) -> None:
+        if not self.redis or token == "no_redis":
+            return
+        script = """
+        if redis.call('GET', KEYS[1]) == ARGV[1] then
+            return redis.call('DEL', KEYS[1])
+        end
+        return 0
+        """
+        await self.redis.eval(script, 1, self.adapter.lock_key, token)
+
+
+_task_poller: TaskPollerService | None = None
+
+
+def get_task_poller() -> TaskPollerService:
+    global _task_poller
+    if _task_poller is None:
+        _task_poller = TaskPollerService(VideoTaskPollerAdapter())
+    return _task_poller

src/services/usage/service.py

@@ -576,6 +576,12 @@ class UsageService:
         """更新已存在的 Usage 记录（内部方法）"""
         # 更新关键字段
         existing_usage.provider_name = usage_params["provider_name"]
+        existing_usage.model = usage_params["model"]
+        existing_usage.request_type = usage_params["request_type"]
+        existing_usage.api_format = usage_params["api_format"]
+        existing_usage.endpoint_api_format = usage_params["endpoint_api_format"]
+        existing_usage.has_format_conversion = usage_params["has_format_conversion"]
+        existing_usage.is_stream = usage_params["is_stream"]
         existing_usage.status = usage_params["status"]
         existing_usage.status_code = usage_params["status_code"]
         existing_usage.error_message = usage_params["error_message"]
@@ -621,6 +627,10 @@ class UsageService:
         existing_usage.provider_endpoint_id = usage_params["provider_endpoint_id"]
         existing_usage.provider_api_key_id = usage_params["provider_api_key_id"]
 
+        # 更新元数据（如 billing_snapshot/dimensions 等）
+        if usage_params.get("request_metadata") is not None:
+            existing_usage.request_metadata = usage_params["request_metadata"]
+
         # 更新模型映射信息
         if target_model is not None:
             existing_usage.target_model = target_model
@@ -1000,6 +1010,11 @@ class UsageService:
                 .values(monthly_used_usd=Provider.monthly_used_usd + actual_total_cost)
             )
 
+        # 结算标记：record_usage_async 写入的 Usage 通常为终态记录
+        if status not in ("pending", "streaming"):
+            usage.billing_status = "settled"
+            usage.finalized_at = datetime.now(timezone.utc)
+
         db.commit()  # 立即提交事务，释放数据库锁
         return usage
 
@@ -1172,6 +1187,11 @@ class UsageService:
                 .values(monthly_used_usd=Provider.monthly_used_usd + actual_total_cost)
             )
 
+        # 结算标记：终态请求写入 settled + finalized_at
+        if status not in ("pending", "streaming"):
+            usage.billing_status = "settled"
+            usage.finalized_at = datetime.now(timezone.utc)
+
         # 提交事务
         try:
             db.commit()
@@ -1297,17 +1317,39 @@ class UsageService:
             is_free_tier=is_free_tier,
         )
 
-        # Upsert（与 record_usage 保持一致）
+        # Upsert（并发幂等：优先用 billing_status 作为结算闸门）
+        from sqlalchemy import update
+
         existing_usage = db.query(Usage).filter(Usage.request_id == request_id).first()
         if existing_usage:
-            # 避免重复记账：若已是终态记录，直接返回（批量接口也采用该策略）
-            if existing_usage.status not in ("pending", "streaming"):
+            # 避免重复记账：若已结算/作废，直接返回（防止并发重复加计数）
+            if getattr(existing_usage, "billing_status", None) in ("settled", "void"):
                 logger.debug(
-                    "record_usage_with_custom_cost: request_id=%s already finalized (status=%s), skip",
+                    "record_usage_with_custom_cost: request_id=%s already finalized (billing_status=%s), skip",
                     request_id,
-                    existing_usage.status,
+                    getattr(existing_usage, "billing_status", None),
                 )
                 return existing_usage
+
+            # 并发闸门：只有 billing_status='pending' 的那一次调用可以继续
+            now = datetime.now(timezone.utc)
+            claim = db.execute(
+                update(Usage)
+                .where(
+                    Usage.request_id == request_id,
+                    Usage.billing_status == "pending",
+                )
+                .values(billing_status="settled", finalized_at=now)
+            )
+            if claim.rowcount != 1:
+                # 已被其他 worker 抢先处理（或被 VOID）
+                latest = db.query(Usage).filter(Usage.request_id == request_id).first()
+                return latest or existing_usage
+
+            # 同步 ORM 对象（避免后续代码读到旧值）
+            existing_usage.billing_status = "settled"
+            existing_usage.finalized_at = now
+
             cls._update_existing_usage(existing_usage, usage_params, target_model)
             usage = existing_usage
         else:
@@ -1382,6 +1424,11 @@ class UsageService:
                 .values(monthly_used_usd=Provider.monthly_used_usd + actual_total_cost)
             )
 
+        # 结算标记：record_usage_with_custom_cost 写入/更新的 Usage 通常为终态记录
+        if status not in ("pending", "streaming"):
+            usage.billing_status = "settled"
+            usage.finalized_at = datetime.now(timezone.utc)
+
         try:
             db.commit()
         except Exception as e:
@@ -2147,35 +2194,31 @@ class UsageService:
     # ========== 请求状态追踪方法 ==========
 
     @classmethod
-    def create_pending_usage(
+    def begin_pending_usage(
         cls,
         db: Session,
         request_id: str,
         user: User | None,
         api_key: ApiKey | None,
         model: str,
+        *,
         is_stream: bool = False,
+        request_type: str = "chat",
         api_format: str | None = None,
         request_headers: dict[str, Any] | None = None,
         request_body: Any | None = None,
     ) -> Usage:
         """
-        创建 pending 状态的使用记录（在请求开始时调用）
+        创建（或返回已有）pending Usage 记录，但**不提交事务**。
 
-        Args:
-            db: 数据库会话
-            request_id: 请求ID
-            user: 用户对象
-            api_key: API Key 对象
-            model: 模型名称
-            is_stream: 是否流式请求
-            api_format: API 格式
-            request_headers: 请求头
-            request_body: 请求体
-
-        Returns:
-            创建的 Usage 记录
+        适用场景：
+        - ApplicationService 在同一事务内创建 pending usage + task + candidates
+        - submit 幂等：重复调用同一 request_id 时返回已有记录
         """
+        existing = db.query(Usage).filter(Usage.request_id == request_id).first()
+        if existing:
+            return existing
+
         # 根据配置决定是否记录请求详情
         should_log_headers = SystemConfigService.should_log_headers(db)
         should_log_body = SystemConfigService.should_log_body(db)
@@ -2204,21 +2247,359 @@ class UsageService:
             output_tokens=0,
             total_tokens=0,
             total_cost_usd=0.0,
-            request_type="chat",
+            request_type=request_type,
             api_format=api_format,
             is_stream=is_stream,
             status="pending",
+            billing_status="pending",
             request_headers=processed_request_headers,
             request_body=processed_request_body,
         )
 
         db.add(usage)
+        db.flush()
+        return usage
+
+    @classmethod
+    def create_pending_usage(
+        cls,
+        db: Session,
+        request_id: str,
+        user: User | None,
+        api_key: ApiKey | None,
+        model: str,
+        is_stream: bool = False,
+        request_type: str = "chat",
+        api_format: str | None = None,
+        request_headers: dict[str, Any] | None = None,
+        request_body: Any | None = None,
+    ) -> Usage:
+        """
+        创建 pending 状态的使用记录（在请求开始时调用）
+
+        Args:
+            db: 数据库会话
+            request_id: 请求ID
+            user: 用户对象
+            api_key: API Key 对象
+            model: 模型名称
+            is_stream: 是否流式请求
+            api_format: API 格式
+            request_headers: 请求头
+            request_body: 请求体
+
+        Returns:
+            创建的 Usage 记录
+        """
+        usage = cls.begin_pending_usage(
+            db,
+            request_id=request_id,
+            user=user,
+            api_key=api_key,
+            model=model,
+            is_stream=is_stream,
+            request_type=request_type,
+            api_format=api_format,
+            request_headers=request_headers,
+            request_body=request_body,
+        )
         db.commit()
 
         logger.debug(f"创建 pending 使用记录: request_id={request_id}, model={model}")
 
         return usage
 
+    # ========== billing_status 并发幂等 finalize ==========
+
+    @classmethod
+    def finalize_settled(
+        cls,
+        db: Session,
+        request_id: str,
+        *,
+        total_cost_usd: float,
+        request_cost_usd: float | None = None,
+        status: str = "completed",
+        status_code: int = 200,
+        error_message: str | None = None,
+        response_time_ms: int | None = None,
+        billing_snapshot: dict[str, Any] | None = None,
+        extra_metadata: dict[str, Any] | None = None,
+    ) -> bool:
+        """
+        并发安全的幂等 finalize（settled）。
+
+        约定：
+        - 仅当 billing_status='pending' 时才会生效（rowcount==1）
+        - 不在本方法内 commit，由调用方决定事务提交时机
+        """
+        from sqlalchemy import update
+
+        now = datetime.now(timezone.utc)
+        cost = float(total_cost_usd)
+        request_cost = float(request_cost_usd) if request_cost_usd is not None else cost
+
+        result = db.execute(
+            update(Usage)
+            .where(
+                Usage.request_id == request_id,
+                Usage.billing_status == "pending",
+            )
+            .values(
+                billing_status="settled",
+                finalized_at=now,
+                total_cost_usd=cost,
+                request_cost_usd=request_cost,
+                status=status,
+                status_code=status_code,
+                error_message=error_message,
+                response_time_ms=response_time_ms,
+            )
+        )
+        if result.rowcount != 1:
+            return False
+
+        # 写入审计快照（只在本次 finalize 生效时执行）
+        usage = db.query(Usage).filter(Usage.request_id == request_id).first()
+        if usage:
+            metadata = usage.request_metadata or {}
+            if billing_snapshot is not None:
+                metadata["billing_snapshot"] = billing_snapshot
+            if extra_metadata:
+                metadata.update(extra_metadata)
+            usage.request_metadata = metadata
+
+        return True
+
+    @classmethod
+    def finalize_void(
+        cls,
+        db: Session,
+        request_id: str,
+        *,
+        reason: str | None = None,
+        status_code: int = 499,
+    ) -> bool:
+        """
+        并发安全的幂等 finalize（void，不收费）。
+
+        约定：
+        - 仅当 billing_status='pending' 时才会生效（rowcount==1）
+        - 不在本方法内 commit，由调用方决定事务提交时机
+        """
+        from sqlalchemy import update
+
+        now = datetime.now(timezone.utc)
+        result = db.execute(
+            update(Usage)
+            .where(
+                Usage.request_id == request_id,
+                Usage.billing_status == "pending",
+            )
+            .values(
+                billing_status="void",
+                finalized_at=now,
+                total_cost_usd=0.0,
+                request_cost_usd=0.0,
+                status="cancelled",
+                status_code=status_code,
+                error_message=reason,
+                response_time_ms=None,
+            )
+        )
+        return result.rowcount == 1
+
+    @classmethod
+    def finalize_submitted(
+        cls,
+        db: Session,
+        request_id: str,
+        *,
+        provider_name: str,
+        provider_id: str | None = None,
+        provider_endpoint_id: str | None = None,
+        provider_api_key_id: str | None = None,
+        response_time_ms: int | None = None,
+        status_code: int = 200,
+        endpoint_api_format: str | None = None,
+        provider_request_headers: dict[str, Any] | None = None,
+        response_headers: dict[str, Any] | None = None,
+        response_body: Any | None = None,
+    ) -> bool:
+        """
+        异步任务提交成功时的幂等结算。
+
+        将 pending 使用记录标记为 settled，费用暂时为 0。
+        后续轮询完成后通过 update_settled_billing 更新实际费用。
+
+        约定：
+        - 仅当 billing_status='pending' 时才会生效（rowcount==1）
+        - 不在本方法内 commit，由调用方决定事务提交时机
+        """
+        from sqlalchemy import update
+
+        now = datetime.now(timezone.utc)
+
+        # 处理响应头和响应体
+        should_log_headers = SystemConfigService.should_log_headers(db)
+        should_log_body = SystemConfigService.should_log_body(db)
+
+        processed_provider_headers = None
+        if should_log_headers and provider_request_headers:
+            processed_provider_headers = SystemConfigService.mask_sensitive_headers(
+                db, provider_request_headers
+            )
+
+        processed_response_headers = None
+        if should_log_headers and response_headers:
+            processed_response_headers = dict(response_headers)
+
+        processed_response_body = None
+        if should_log_body and response_body:
+            processed_response_body = SystemConfigService.truncate_body(
+                db, response_body, is_request=False
+            )
+
+        values: dict[str, Any] = {
+            "billing_status": "settled",
+            "finalized_at": now,
+            "total_cost_usd": 0.0,
+            "request_cost_usd": 0.0,
+            "status": "completed",
+            "status_code": status_code,
+            "response_time_ms": response_time_ms,
+            "provider_name": provider_name,
+            "provider_id": provider_id,
+            "provider_endpoint_id": provider_endpoint_id,
+            "provider_api_key_id": provider_api_key_id,
+            "endpoint_api_format": endpoint_api_format,
+        }
+
+        if processed_provider_headers is not None:
+            values["provider_request_headers"] = processed_provider_headers
+        if processed_response_headers is not None:
+            values["response_headers"] = processed_response_headers
+        if processed_response_body is not None:
+            values["response_body"] = processed_response_body
+
+        result = db.execute(
+            update(Usage)
+            .where(
+                Usage.request_id == request_id,
+                Usage.billing_status == "pending",
+            )
+            .values(**values)
+        )
+        return result.rowcount == 1
+
+    @classmethod
+    def update_settled_billing(
+        cls,
+        db: Session,
+        request_id: str,
+        *,
+        total_cost_usd: float,
+        request_cost_usd: float | None = None,
+        status: str = "completed",
+        status_code: int = 200,
+        error_message: str | None = None,
+        response_time_ms: int | None = None,
+        billing_snapshot: dict[str, Any] | None = None,
+        extra_metadata: dict[str, Any] | None = None,
+    ) -> bool:
+        """
+        更新已结算记录的计费信息（用于异步任务轮询完成后）。
+
+        与 finalize_settled 不同：
+        - finalize_settled: pending -> settled（首次结算）
+        - update_settled_billing: settled -> settled（更新费用）
+
+        约定：
+        - 仅当 billing_status='settled' 时才会生效
+        - 不在本方法内 commit，由调用方决定事务提交时机
+        """
+        from sqlalchemy import update
+
+        now = datetime.now(timezone.utc)
+        cost = float(total_cost_usd)
+        request_cost = float(request_cost_usd) if request_cost_usd is not None else cost
+
+        values: dict[str, Any] = {
+            "total_cost_usd": cost,
+            "request_cost_usd": request_cost,
+            "status": status,
+            "status_code": status_code,
+        }
+        if error_message is not None:
+            values["error_message"] = error_message
+        if response_time_ms is not None:
+            values["response_time_ms"] = response_time_ms
+
+        result = db.execute(
+            update(Usage)
+            .where(
+                Usage.request_id == request_id,
+                Usage.billing_status == "settled",
+            )
+            .values(**values)
+        )
+        if result.rowcount != 1:
+            return False
+
+        # 写入审计快照
+        usage = db.query(Usage).filter(Usage.request_id == request_id).first()
+        if usage:
+            metadata = usage.request_metadata or {}
+            if billing_snapshot is not None:
+                metadata["billing_snapshot"] = billing_snapshot
+            if extra_metadata:
+                metadata.update(extra_metadata)
+            metadata["billing_updated_at"] = now.isoformat()
+            usage.request_metadata = metadata
+
+        return True
+
+    @classmethod
+    def void_settled(
+        cls,
+        db: Session,
+        request_id: str,
+        *,
+        reason: str | None = None,
+        status_code: int = 499,
+    ) -> bool:
+        """
+        将已结算的记录作废（用于异步任务取消）。
+
+        与 finalize_void 不同：
+        - finalize_void: pending -> void（未结算时作废）
+        - void_settled: settled -> void（已结算后取消，费用归零）
+
+        约定：
+        - 仅当 billing_status='settled' 时才会生效
+        - 不在本方法内 commit，由调用方决定事务提交时机
+        """
+        from sqlalchemy import update
+
+        now = datetime.now(timezone.utc)
+        result = db.execute(
+            update(Usage)
+            .where(
+                Usage.request_id == request_id,
+                Usage.billing_status == "settled",
+            )
+            .values(
+                billing_status="void",
+                finalized_at=now,
+                total_cost_usd=0.0,
+                request_cost_usd=0.0,
+                status="cancelled",
+                status_code=status_code,
+                error_message=reason,
+            )
+        )
+        return result.rowcount == 1
+
     @classmethod
     def update_usage_status(
         cls,
@@ -2235,6 +2616,7 @@ class UsageService:
         api_format: str | None = None,
         endpoint_api_format: str | None = None,
         has_format_conversion: bool | None = None,
+        status_code: int | None = None,
     ) -> Usage | None:
         """
         快速更新使用记录状态
@@ -2253,6 +2635,7 @@ class UsageService:
             api_format: API 格式（可选，用于获取按格式配置的倍率）
             endpoint_api_format: 端点原生 API 格式（可选）
             has_format_conversion: 是否发生了格式转换（可选）
+            status_code: HTTP 状态码（可选）
 
         Returns:
             更新后的 Usage 记录，如果未找到则返回 None
@@ -2295,6 +2678,16 @@ class UsageService:
             usage.endpoint_api_format = endpoint_api_format
         if has_format_conversion is not None:
             usage.has_format_conversion = has_format_conversion
+        if status_code is not None:
+            usage.status_code = status_code
+
+        # 结算状态：当请求进入终态时，将 billing_status 标记为 settled
+        # 注意：取消是否应 VOID/部分结算由更高层策略决定；这里默认终态均视为已结算。
+        if status in ("completed", "failed", "cancelled"):
+            if getattr(usage, "billing_status", None) == "pending":
+                usage.billing_status = "settled"
+            if getattr(usage, "finalized_at", None) is None:
+                usage.finalized_at = datetime.now(timezone.utc)
 
         db.commit()
 

src/services/video/__init__.py

@@ -1,10 +0,0 @@
-"""
-视频相关服务
-"""
-
-from src.services.video.task_poller import VideoTaskPollerService, get_video_task_poller
-
-__all__ = [
-    "VideoTaskPollerService",
-    "get_video_task_poller",
-]

src/services/video/task_poller.py

@@ -1,446 +0,0 @@
-"""
-视频任务后台轮询服务
-"""
-
-from __future__ import annotations
-
-import asyncio
-from datetime import datetime, timedelta, timezone
-from typing import Any
-from uuid import uuid4
-
-from sqlalchemy.orm import Session
-
-from src.api.handlers.base.request_builder import ProviderAuthInfo, get_provider_auth
-from src.api.handlers.base.video_handler_base import (
-    normalize_gemini_operation_id,
-    sanitize_error_message,
-)
-from src.clients.http_client import HTTPClientPool
-from src.clients.redis_client import get_redis_client
-from src.config.settings import config
-from src.core.api_format import (
-    build_upstream_headers_for_endpoint,
-    get_extra_headers_from_endpoint,
-    make_signature_key,
-)
-from src.core.api_format.conversion.internal_video import InternalVideoPollResult, VideoStatus
-from src.core.api_format.conversion.normalizers.gemini import GeminiNormalizer
-from src.core.api_format.conversion.normalizers.openai import OpenAINormalizer
-from src.core.crypto import crypto_service
-from src.core.logger import logger
-from src.database import create_session
-from src.models.database import ProviderAPIKey, ProviderEndpoint, VideoTask
-from src.services.system.scheduler import get_scheduler
-from src.services.task.impl.video_telemetry import VideoTelemetry
-
-# 永久性错误指示词（用于降级判断，不应重试）
-_PERMANENT_ERROR_INDICATORS = frozenset(
-    {
-        "not found",
-        "404",
-        "unauthorized",
-        "401",
-        "forbidden",
-        "403",
-        "invalid request",
-        "invalid api key",
-        "does not exist",
-    }
-)
-
-
-class PollHTTPError(RuntimeError):
-    """HTTP 轮询错误，携带状态码便于区分临时/永久错误"""
-
-    def __init__(self, status_code: int, message: str):
-        super().__init__(message)
-        self.status_code = status_code
-
-
-class VideoTaskPollerService:
-    """后台轮询视频生成任务状态"""
-
-    LOCK_KEY = "video_task_poller:lock"
-    LOCK_TTL = 60
-    MAX_BACKOFF_SECONDS = 300
-    # 连续失败告警阈值
-    CONSECUTIVE_FAILURE_ALERT_THRESHOLD = 5
-
-    def __init__(self) -> None:
-        self._lock = asyncio.Lock()
-        self.redis = None
-        self._openai_normalizer = OpenAINormalizer()
-        self._gemini_normalizer = GeminiNormalizer()
-        # 追踪连续失败次数（用于告警）
-        self._consecutive_failures = 0
-        # 从配置读取参数
-        self._batch_size = config.video_poll_batch_size
-        self._concurrency = config.video_poll_concurrency
-        # Semaphore 延迟初始化，避免在事件循环外创建
-        self._semaphore: asyncio.Semaphore | None = None
-
-    async def start(self) -> None:
-        # 在事件循环内初始化 Semaphore
-        if self._semaphore is None:
-            self._semaphore = asyncio.Semaphore(self._concurrency)
-        if self.redis is None:
-            self.redis = await get_redis_client(require_redis=False)
-
-        scheduler = get_scheduler()
-        scheduler.add_interval_job(
-            self.poll_pending_tasks,
-            seconds=config.video_poll_interval_seconds,
-            job_id="video_task_poller",
-            name="视频任务轮询",
-        )
-
-    async def stop(self) -> None:
-        """停止轮询服务"""
-        scheduler = get_scheduler()
-        scheduler.remove_job("video_task_poller")
-
-    async def poll_pending_tasks(self) -> None:
-        async with self._lock:
-            token = await self._acquire_redis_lock()
-            if token is None:
-                return
-
-            try:
-                with create_session() as db:
-                    now = datetime.now(timezone.utc)
-                    tasks = (
-                        db.query(VideoTask)
-                        .filter(
-                            VideoTask.status.in_(
-                                [
-                                    VideoStatus.SUBMITTED.value,
-                                    VideoStatus.QUEUED.value,
-                                    VideoStatus.PROCESSING.value,
-                                ]
-                            ),
-                            VideoTask.next_poll_at <= now,
-                            VideoTask.poll_count < VideoTask.max_poll_count,
-                        )
-                        .order_by(VideoTask.next_poll_at.asc())
-                        .limit(self._batch_size)
-                        .all()
-                    )
-
-                    if not tasks:
-                        # 无任务时重置连续失败计数
-                        self._consecutive_failures = 0
-                        return
-
-                    # 提取任务 ID 列表，释放查询 session 后逐个轮询
-                    task_ids = [t.id for t in tasks]
-
-                # 并发轮询：每个任务使用独立 session，避免共享 session 的并发风险
-                poll_results: list[bool] = []
-
-                # 确保 semaphore 已初始化（在 start 中初始化，此处防御性检查）
-                if self._semaphore is None:
-                    self._semaphore = asyncio.Semaphore(self._concurrency)
-                semaphore = self._semaphore
-
-                async def poll_with_semaphore(task_id: str) -> None:
-                    """带信号量的轮询，结果写入 poll_results"""
-                    async with semaphore:
-                        try:
-                            with create_session() as task_db:
-                                task_obj = task_db.query(VideoTask).get(task_id)
-                                if not task_obj:
-                                    logger.warning("Task %s disappeared during poll", task_id)
-                                    poll_results.append(True)
-                                    return
-                                await self._poll_single_task(task_db, task_obj)
-                                task_db.commit()
-                            poll_results.append(True)
-                        except Exception as exc:
-                            logger.exception(
-                                "Unexpected error polling task %s: %s",
-                                task_id,
-                                sanitize_error_message(str(exc)),
-                            )
-                            poll_results.append(False)
-
-                async with asyncio.TaskGroup() as tg:
-                    for tid in task_ids:
-                        tg.create_task(poll_with_semaphore(tid))
-
-                batch_failures = sum(1 for r in poll_results if r is False)
-
-                # 更新连续失败计数并检查告警阈值
-                if batch_failures == len(task_ids):
-                    self._consecutive_failures += 1
-                    if self._consecutive_failures >= self.CONSECUTIVE_FAILURE_ALERT_THRESHOLD:
-                        logger.error(
-                            "[ALERT] Video task poller: %d consecutive batches failed. "
-                            "Provider connectivity or configuration issue suspected.",
-                            self._consecutive_failures,
-                        )
-                else:
-                    self._consecutive_failures = 0
-            finally:
-                await self._release_redis_lock(token)
-
-    async def _poll_single_task(self, db: Session, task: VideoTask) -> None:
-        try:
-            result = await self._poll_task_status(db, task)
-            if result.status == VideoStatus.COMPLETED:
-                task.status = VideoStatus.COMPLETED.value
-                task.video_url = result.video_url
-                task.video_expires_at = result.expires_at
-                task.completed_at = datetime.now(timezone.utc)
-                task.progress_percent = 100
-                # 存储多视频 URL（Gemini sampleCount > 1 时）
-                if result.video_urls:
-                    task.video_urls = result.video_urls
-                # 保存上游原始响应（用于审计/重算）
-                self._attach_poll_raw_response(task, result)
-            elif result.status == VideoStatus.FAILED:
-                task.status = VideoStatus.FAILED.value
-                task.error_code = result.error_code
-                task.error_message = result.error_message
-                task.completed_at = datetime.now(timezone.utc)
-                self._attach_poll_raw_response(task, result)
-            else:
-                task.poll_count += 1
-                task.progress_percent = result.progress_percent
-                task.next_poll_at = datetime.now(timezone.utc) + timedelta(
-                    seconds=task.poll_interval_seconds
-                )
-        except Exception as exc:
-            task.poll_count += 1
-            error_msg = sanitize_error_message(str(exc))
-            logger.warning("Poll error for task %s: %s", task.id, error_msg)
-            task.progress_message = f"Poll error: {error_msg}"
-
-            # 区分临时性错误和永久性错误
-            status_code = exc.status_code if isinstance(exc, PollHTTPError) else None
-            is_permanent = self._is_permanent_error(exc, status_code=status_code)
-            if is_permanent:
-                task.status = VideoStatus.FAILED.value
-                task.error_code = "poll_permanent_error"
-                task.error_message = error_msg
-                task.completed_at = datetime.now(timezone.utc)
-            else:
-                # 临时性错误：指数退避重试
-                backoff = min(
-                    task.poll_interval_seconds * (2 ** min(task.retry_count, 5)),
-                    self.MAX_BACKOFF_SECONDS,
-                )
-                task.retry_count += 1
-                task.next_poll_at = datetime.now(timezone.utc) + timedelta(seconds=backoff)
-
-        # 检查是否超过最大轮询次数（超时）
-        task.updated_at = datetime.now(timezone.utc)
-        if task.poll_count >= task.max_poll_count and task.status not in [
-            VideoStatus.COMPLETED.value,
-            VideoStatus.FAILED.value,
-            VideoStatus.CANCELLED.value,
-        ]:
-            task.status = VideoStatus.FAILED.value
-            task.error_code = "poll_timeout"
-            task.error_message = f"Task timed out after {task.poll_count} polls"
-            task.completed_at = datetime.now(timezone.utc)
-
-        # 终态写入 Usage（复用外层 per-task session）
-        if task.status in (VideoStatus.COMPLETED.value, VideoStatus.FAILED.value):
-            try:
-                await VideoTelemetry(db, redis_client=self.redis).record_terminal_usage(task)
-            except Exception as exc:
-                logger.exception(
-                    "Failed to record video usage for task=%s: %s",
-                    task.id,
-                    sanitize_error_message(str(exc)),
-                )
-
-    def _attach_poll_raw_response(self, task: VideoTask, result: InternalVideoPollResult) -> None:
-        if not result.raw_response:
-            return
-        if task.request_metadata is None:
-            task.request_metadata = {}
-        # 仅在终态写一次，避免污染 request_metadata
-        task.request_metadata["poll_raw_response"] = result.raw_response
-
-    def _is_permanent_error(self, exc: Exception, status_code: int | None = None) -> bool:
-        """判断是否为永久性错误（不应重试）"""
-        # 优先使用 HTTP 状态码判断
-        if status_code is not None:
-            # 4xx 客户端错误（除 429 限流）通常是永久性错误
-            return 400 <= status_code < 500 and status_code != 429
-
-        # 降级到字符串匹配
-        error_msg = str(exc).lower()
-        return any(indicator in error_msg for indicator in _PERMANENT_ERROR_INDICATORS)
-
-    async def _poll_task_status(self, db: Session, task: VideoTask) -> InternalVideoPollResult:
-        if not task.endpoint_id or not task.key_id:
-            return InternalVideoPollResult(
-                status=VideoStatus.FAILED,
-                error_code="missing_provider_info",
-                error_message="Task missing endpoint_id or key_id",
-            )
-        endpoint = self._get_endpoint(db, task.endpoint_id)
-        key = self._get_key(db, task.key_id)
-        if not key.api_key:
-            return InternalVideoPollResult(
-                status=VideoStatus.FAILED,
-                error_code="provider_config_error",
-                error_message="Provider key not properly configured",
-            )
-        try:
-            upstream_key = crypto_service.decrypt(key.api_key)
-        except Exception:
-            logger.warning("Failed to decrypt provider key for task %s", task.id)
-            return InternalVideoPollResult(
-                status=VideoStatus.FAILED,
-                error_code="decryption_error",
-                error_message="Failed to decrypt provider key",
-            )
-
-        provider_format = (task.provider_api_format or "").strip().lower()
-        if not provider_format:
-            provider_format = make_signature_key(
-                str(getattr(endpoint, "api_family", "")).strip().lower(),
-                str(getattr(endpoint, "endpoint_kind", "")).strip().lower(),
-            )
-
-        if provider_format.startswith("gemini:"):
-            auth_info = await get_provider_auth(endpoint, key)
-            return await self._poll_gemini(task, endpoint, upstream_key, auth_info)
-        return await self._poll_openai(task, endpoint, upstream_key)
-
-    async def _poll_openai(
-        self,
-        task: VideoTask,
-        endpoint: ProviderEndpoint,
-        upstream_key: str,
-    ) -> InternalVideoPollResult:
-        if not task.external_task_id:
-            return InternalVideoPollResult(
-                status=VideoStatus.FAILED,
-                error_code="missing_external_task_id",
-                error_message="Task missing external_task_id",
-            )
-        url = self._build_openai_url(endpoint.base_url, task.external_task_id)
-        endpoint_sig = (task.provider_api_format or "").strip().lower() or make_signature_key(
-            str(getattr(endpoint, "api_family", "")).strip().lower(),
-            str(getattr(endpoint, "endpoint_kind", "")).strip().lower(),
-        )
-        headers = self._build_headers(endpoint_sig, upstream_key, endpoint)
-
-        client = await HTTPClientPool.get_default_client_async()
-        response = await client.get(url, headers=headers)
-        if response.status_code >= 400:
-            raise PollHTTPError(
-                response.status_code,
-                sanitize_error_message(response.text or "Poll error"),
-            )
-
-        payload = response.json()
-        return self._openai_normalizer.video_poll_to_internal(payload)
-
-    async def _poll_gemini(
-        self,
-        task: VideoTask,
-        endpoint: ProviderEndpoint,
-        upstream_key: str,
-        auth_info: ProviderAuthInfo | None,
-    ) -> InternalVideoPollResult:
-        if not task.external_task_id:
-            return InternalVideoPollResult(
-                status=VideoStatus.FAILED,
-                error_code="missing_external_task_id",
-                error_message="Task missing external_task_id",
-            )
-        operation_name = normalize_gemini_operation_id(task.external_task_id)
-        url = self._build_gemini_url(endpoint.base_url, operation_name)
-        endpoint_sig = (task.provider_api_format or "").strip().lower() or make_signature_key(
-            str(getattr(endpoint, "api_family", "")).strip().lower(),
-            str(getattr(endpoint, "endpoint_kind", "")).strip().lower(),
-        )
-        headers = self._build_headers(endpoint_sig, upstream_key, endpoint, auth_info)
-
-        client = await HTTPClientPool.get_default_client_async()
-        response = await client.get(url, headers=headers)
-        if response.status_code >= 400:
-            raise PollHTTPError(
-                response.status_code,
-                sanitize_error_message(response.text or "Poll error"),
-            )
-
-        payload = response.json()
-        return self._gemini_normalizer.video_poll_to_internal(payload)
-
-    def _build_openai_url(self, base_url: str | None, task_id: str) -> str:
-        base = (base_url or "https://api.openai.com").rstrip("/")
-        if base.endswith("/v1"):
-            return f"{base}/videos/{task_id}"
-        return f"{base}/v1/videos/{task_id}"
-
-    def _build_gemini_url(self, base_url: str | None, operation_name: str) -> str:
-        base = (base_url or "https://generativelanguage.googleapis.com").rstrip("/")
-        if base.endswith("/v1beta"):
-            base = base[: -len("/v1beta")]
-        return f"{base}/v1beta/{operation_name}"
-
-    def _build_headers(
-        self,
-        endpoint_sig: str,
-        upstream_key: str,
-        endpoint: ProviderEndpoint,
-        auth_info: ProviderAuthInfo | None = None,
-    ) -> dict[str, str]:
-        extra_headers = get_extra_headers_from_endpoint(endpoint)
-        headers = build_upstream_headers_for_endpoint(
-            {},
-            endpoint_sig,
-            upstream_key,
-            endpoint_headers=extra_headers,
-        )
-        if auth_info:
-            headers.pop("x-goog-api-key", None)
-            headers[auth_info.auth_header] = auth_info.auth_value
-        return headers
-
-    def _get_endpoint(self, db: Session, endpoint_id: str) -> ProviderEndpoint:
-        endpoint = db.query(ProviderEndpoint).filter(ProviderEndpoint.id == endpoint_id).first()
-        if not endpoint:
-            raise RuntimeError("Provider endpoint not found")
-        return endpoint
-
-    def _get_key(self, db: Session, key_id: str) -> ProviderAPIKey:
-        key = db.query(ProviderAPIKey).filter(ProviderAPIKey.id == key_id).first()
-        if not key:
-            raise RuntimeError("Provider key not found")
-        return key
-
-    async def _acquire_redis_lock(self) -> str | None:
-        if not self.redis:
-            return "no_redis"
-        token = str(uuid4())
-        acquired = await self.redis.set(self.LOCK_KEY, token, nx=True, ex=self.LOCK_TTL)
-        return token if acquired else None
-
-    async def _release_redis_lock(self, token: str) -> None:
-        if not self.redis or token == "no_redis":
-            return
-        script = """
-        if redis.call('GET', KEYS[1]) == ARGV[1] then
-            return redis.call('DEL', KEYS[1])
-        end
-        return 0
-        """
-        await self.redis.eval(script, 1, self.LOCK_KEY, token)
-
-
-_video_task_poller: VideoTaskPollerService | None = None
-
-
-def get_video_task_poller() -> VideoTaskPollerService:
-    global _video_task_poller
-    if _video_task_poller is None:
-        _video_task_poller = VideoTaskPollerService()
-    return _video_task_poller