refactor(migrations): add idempotency checks to migration scripts

alembic/versions/20251214_1300_e9b3d63f0cbf_remove_model_mappings_add_aliases.py

@@ -26,16 +26,66 @@ branch_labels = None
 depends_on = None
 
 
+def column_exists(bind, table_name: str, column_name: str) -> bool:
+    """检查列是否存在"""
+    result = bind.execute(
+        sa.text(
+            """
+            SELECT EXISTS (
+                SELECT 1 FROM information_schema.columns
+                WHERE table_name = :table_name AND column_name = :column_name
+            )
+            """
+        ),
+        {"table_name": table_name, "column_name": column_name},
+    )
+    return result.scalar()
+
+
+def table_exists(bind, table_name: str) -> bool:
+    """检查表是否存在"""
+    result = bind.execute(
+        sa.text(
+            """
+            SELECT EXISTS (
+                SELECT 1 FROM information_schema.tables
+                WHERE table_name = :table_name
+            )
+            """
+        ),
+        {"table_name": table_name},
+    )
+    return result.scalar()
+
+
+def index_exists(bind, index_name: str) -> bool:
+    """检查索引是否存在"""
+    result = bind.execute(
+        sa.text(
+            """
+            SELECT EXISTS (
+                SELECT 1 FROM pg_indexes
+                WHERE indexname = :index_name
+            )
+            """
+        ),
+        {"index_name": index_name},
+    )
+    return result.scalar()
+
+
 def upgrade() -> None:
     """添加 provider_model_aliases 字段，迁移数据，删除 model_mappings 表"""
-    # 1. 添加 provider_model_aliases 字段
+    bind = op.get_bind()
+
+    # 1. 添加 provider_model_aliases 字段（如果不存在）
+    if not column_exists(bind, "models", "provider_model_aliases"):
         op.add_column(
             'models',
             sa.Column('provider_model_aliases', sa.JSON(), nullable=True)
         )
 
-    # 2. 迁移 model_mappings 数据
+    # 2. 迁移 model_mappings 数据（如果表存在）
-    bind = op.get_bind()
     session = Session(bind=bind)
 
     model_mappings_table = sa.table(
@@ -96,6 +146,8 @@ def upgrade() -> None:
 
     # 查询所有活跃的 provider 级别 alias（只迁移 is_active=True 且 mapping_type='alias' 的）
     # 全局别名/映射不迁移（新架构不再支持 source_model -> GlobalModel.name 的解析）
+    # 仅当 model_mappings 表存在时执行迁移
+    if table_exists(bind, "model_mappings"):
         mappings = session.execute(
             sa.select(
                 model_mappings_table.c.source_model,
@@ -177,7 +229,8 @@ def upgrade() -> None:
         op.drop_table('model_mappings')
 
     # 4. 添加索引优化别名解析性能
-    # provider_model_name 索引（支持精确匹配）
+    # provider_model_name 索引（支持精确匹配，如果不存在）
+    if not index_exists(bind, "idx_model_provider_model_name"):
         op.create_index(
             "idx_model_provider_model_name",
             "models",
@@ -189,11 +242,22 @@ def upgrade() -> None:
     # provider_model_aliases GIN 索引（支持 JSONB 查询，仅 PostgreSQL）
     if bind.dialect.name == "postgresql":
         # 将 json 列转为 jsonb（jsonb 性能更好且支持 GIN 索引）
+        # 使用 IF NOT EXISTS 风格的检查来避免重复转换
         op.execute(
             """
+            DO $$
+            BEGIN
+                IF EXISTS (
+                    SELECT 1 FROM information_schema.columns
+                    WHERE table_name = 'models'
+                    AND column_name = 'provider_model_aliases'
+                    AND data_type = 'json'
+                ) THEN
                     ALTER TABLE models
                     ALTER COLUMN provider_model_aliases TYPE jsonb
-            USING provider_model_aliases::jsonb
+                    USING provider_model_aliases::jsonb;
+                END IF;
+            END $$;
             """
         )
         # 创建 GIN 索引

alembic/versions/20251215_1707_180e63a9c83a_add_first_byte_time_ms_to_usage_table.py

@@ -5,8 +5,8 @@ Revises: e9b3d63f0cbf
 Create Date: 2025-12-15 17:07:44.631032+00:00
 
 """
-from alembic import op
 import sqlalchemy as sa
+from alembic import op
 
 
 # revision identifiers, used by Alembic.
@@ -16,9 +16,28 @@ branch_labels = None
 depends_on = None
 
 
+def column_exists(bind, table_name: str, column_name: str) -> bool:
+    """检查列是否存在"""
+    result = bind.execute(
+        sa.text(
+            """
+            SELECT EXISTS (
+                SELECT 1 FROM information_schema.columns
+                WHERE table_name = :table_name AND column_name = :column_name
+            )
+            """
+        ),
+        {"table_name": table_name, "column_name": column_name},
+    )
+    return result.scalar()
+
+
 def upgrade() -> None:
     """应用迁移：升级到新版本"""
-    # 添加首字时间字段到 usage 表
+    bind = op.get_bind()
+
+    # 添加首字时间字段到 usage 表（如果不存在）
+    if not column_exists(bind, "usage", "first_byte_time_ms"):
         op.add_column('usage', sa.Column('first_byte_time_ms', sa.Integer(), nullable=True))
 
 

alembic/versions/20251216_0311_1cc6942cf06f_refactor_global_model_to_use_config_.py

@@ -5,8 +5,8 @@ Revises: 180e63a9c83a
 Create Date: 2025-12-16 03:11:32.480976+00:00
 
 """
-from alembic import op
 import sqlalchemy as sa
+from alembic import op
 from sqlalchemy.dialects import postgresql
 
 # revision identifiers, used by Alembic.
@@ -16,6 +16,22 @@ branch_labels = None
 depends_on = None
 
 
+def column_exists(bind, table_name: str, column_name: str) -> bool:
+    """检查列是否存在"""
+    result = bind.execute(
+        sa.text(
+            """
+            SELECT EXISTS (
+                SELECT 1 FROM information_schema.columns
+                WHERE table_name = :table_name AND column_name = :column_name
+            )
+            """
+        ),
+        {"table_name": table_name, "column_name": column_name},
+    )
+    return result.scalar()
+
+
 def upgrade() -> None:
     """应用迁移：升级到新版本
 
@@ -23,14 +39,22 @@ def upgrade() -> None:
     2. 把旧数据迁移到 config
     3. 删除旧列
     """
+    bind = op.get_bind()
+
+    # 检查是否已经迁移过（config 列存在且旧列不存在）
+    has_config = column_exists(bind, "global_models", "config")
+    has_old_columns = column_exists(bind, "global_models", "default_supports_streaming")
+
+    if has_config and not has_old_columns:
+        # 已完成迁移，跳过
+        return
+
     # 1. 添加 config 列（使用 JSONB 类型，支持索引和更高效的查询）
+    if not has_config:
         op.add_column('global_models', sa.Column('config', postgresql.JSONB(), nullable=True))
 
-    # 2. 迁移数据：把旧字段合并到 config JSON
+    # 2. 迁移数据：把旧字段合并到 config JSON（仅当旧列存在时）
-    # 注意：使用 COALESCE 为布尔字段设置默认值，避免数据丢失
+    if has_old_columns:
-    # - streaming 默认 true（大多数模型支持）
-    # - 其他能力默认 false
-    # - jsonb_strip_nulls 只移除 null 字段，不影响 false 值
         op.execute("""
             UPDATE global_models
             SET config = jsonb_strip_nulls(jsonb_build_object(