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41719a00e7
实现两种锁清理模式： - 单实例模式（默认）：启动时使用 Lua 脚本原子性清理旧锁，解决 worker 重启时���锁残留问题 - 多实例模式：使用 NX 选项竞争锁，依赖 TTL 处理异常退出 可通过 SINGLE_INSTANCE_MODE 环境变量控制模式选择。
151 lines
5.9 KiB
Python
151 lines
5.9 KiB
Python
"""分布式任务协调器，确保仅有一个 worker 执行特定任务
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锁清理策略：
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- 单实例模式（默认）：启动时使用原子操作清理旧锁并获取新锁
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- 多实例模式：使用 NX 选项竞争锁，依赖 TTL 处理异常退出
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使用方式：
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- 默认行为：启动时清理旧锁（适用于单机部署）
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- 多实例部署：设置 SINGLE_INSTANCE_MODE=false 禁用启动清理
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"""
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from __future__ import annotations
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import os
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import pathlib
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import uuid
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from typing import Dict, Optional
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from src.core.logger import logger
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try:
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import fcntl # type: ignore
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except ImportError: # pragma: no cover - Windows 环境
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fcntl = None
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class StartupTaskCoordinator:
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"""利用 Redis 或文件锁，保证任务只在单个进程/实例中运行"""
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# 类级别标记：在当前进程中是否已尝试过启动清理
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# 注意：这在 fork 模式下每个 worker 都是独立的
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_startup_cleanup_attempted = False
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def __init__(self, redis_client=None, lock_dir: Optional[str] = None):
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self.redis = redis_client
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self._tokens: Dict[str, str] = {}
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self._file_handles: Dict[str, object] = {}
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self._lock_dir = pathlib.Path(lock_dir or os.getenv("TASK_LOCK_DIR", "./.locks"))
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if not self._lock_dir.exists():
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self._lock_dir.mkdir(parents=True, exist_ok=True)
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# 单实例模式：启动时清理旧锁（适用于单机部署，避免残留锁问题）
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self._single_instance_mode = os.getenv("SINGLE_INSTANCE_MODE", "true").lower() == "true"
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def _redis_key(self, name: str) -> str:
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return f"task_lock:{name}"
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async def acquire(self, name: str, ttl: Optional[int] = None) -> bool:
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ttl = ttl or int(os.getenv("TASK_COORDINATOR_LOCK_TTL", "86400"))
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if self.redis:
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token = str(uuid.uuid4())
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try:
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if self._single_instance_mode:
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# 单实例模式：使用 Lua 脚本原子性地"清理旧锁 + 竞争获取"
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# 只有当锁不存在或成功获取时才返回 1
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# 这样第一个执行的 worker 会清理旧锁并获取，后续 worker 会正常竞争
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script = """
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local key = KEYS[1]
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local token = ARGV[1]
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local ttl = tonumber(ARGV[2])
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local startup_key = KEYS[1] .. ':startup'
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-- 检查是否已有 worker 执行过启动清理
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local cleaned = redis.call('GET', startup_key)
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if not cleaned then
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-- 第一个 worker：删除旧锁，标记已清理
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redis.call('DEL', key)
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redis.call('SET', startup_key, '1', 'EX', 60)
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end
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-- 尝试获取锁（NX 模式）
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local result = redis.call('SET', key, token, 'NX', 'EX', ttl)
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if result then
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return 1
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end
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return 0
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"""
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result = await self.redis.eval(
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script, 2,
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self._redis_key(name), self._redis_key(name),
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token, ttl
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)
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if result == 1:
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self._tokens[name] = token
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logger.info(f"任务 {name} 通过 Redis 锁独占执行")
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return True
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return False
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else:
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# 多实例模式：直接使用 NX 选项竞争锁
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acquired = await self.redis.set(
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self._redis_key(name), token, nx=True, ex=ttl
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)
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if acquired:
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self._tokens[name] = token
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logger.info(f"任务 {name} 通过 Redis 锁独占执行")
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return True
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return False
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except Exception as exc: # pragma: no cover - Redis 异常回退
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logger.warning(f"Redis 锁获取失败，回退到文件锁: {exc}")
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return await self._acquire_file_lock(name)
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async def release(self, name: str):
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if self.redis and name in self._tokens:
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token = self._tokens.pop(name)
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script = """
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if redis.call('GET', KEYS[1]) == ARGV[1] then
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return redis.call('DEL', KEYS[1])
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end
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return 0
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"""
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try:
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await self.redis.eval(script, 1, self._redis_key(name), token)
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except Exception as exc: # pragma: no cover
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logger.warning(f"释放 Redis 锁失败: {exc}")
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handle = self._file_handles.pop(name, None)
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if handle and fcntl:
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try:
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fcntl.flock(handle, fcntl.LOCK_UN)
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finally:
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handle.close()
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async def _acquire_file_lock(self, name: str) -> bool:
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if fcntl is None:
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# 在不支持 fcntl 的平台上退化为单进程锁
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if name in self._file_handles:
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return False
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self._file_handles[name] = object()
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logger.warning("操作系统不支持文件锁，任务锁仅在当前进程生效")
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return True
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lock_path = self._lock_dir / f"{name}.lock"
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handle = open(lock_path, "a+")
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try:
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fcntl.flock(handle, fcntl.LOCK_EX | fcntl.LOCK_NB)
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self._file_handles[name] = handle
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logger.info(f"任务 {name} 使用文件锁独占执行")
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return True
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except BlockingIOError:
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handle.close()
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return False
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async def ensure_singleton_task(name: str, redis_client=None, ttl: Optional[int] = None):
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"""便捷协程，返回 (coordinator, acquired)"""
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coordinator = StartupTaskCoordinator(redis_client)
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acquired = await coordinator.acquire(name, ttl=ttl)
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return coordinator, acquired
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