step 12

alembic/env.py

@@ -0,0 +1,93 @@
+"""Alembic migration environment — async-compatible.
+
+At runtime the app uses ``postgresql+asyncpg://``.  Alembic's CLI is
+synchronous, so we derive a *sync* psycopg2 URL from the same DATABASE_URL
+env var by replacing the driver prefix.
+
+Run migrations with:
+    alembic upgrade head
+"""
+
+from __future__ import annotations
+
+import asyncio
+import os
+import re
+from logging.config import fileConfig
+
+from alembic import context
+from sqlalchemy import engine_from_config, pool
+from sqlalchemy.ext.asyncio import create_async_engine
+
+# Alembic Config object (gives access to alembic.ini values).
+config = context.config
+
+# Set up Python logging from alembic.ini.
+if config.config_file_name is not None:
+    fileConfig(config.config_file_name)
+
+# Import the Base so that Alembic can detect model changes for --autogenerate.
+from app.models import Base  # noqa: E402
+
+target_metadata = Base.metadata
+
+
+def _sync_url(async_url: str) -> str:
+    """Convert an asyncpg URL to a psycopg2 URL for Alembic CLI."""
+    return re.sub(r"postgresql\+asyncpg", "postgresql+psycopg2", async_url)
+
+
+def _get_url() -> str:
+    db_url = os.environ.get("DATABASE_URL", "")
+    if not db_url:
+        # Fall back to settings if env var not set directly.
+        from app.config.settings import settings  # noqa: PLC0415
+        db_url = settings.DATABASE_URL
+    return _sync_url(db_url)
+
+
+def run_migrations_offline() -> None:
+    """Emit SQL without a live DB connection."""
+    url = _get_url()
+    context.configure(
+        url=url,
+        target_metadata=target_metadata,
+        literal_binds=True,
+        dialect_opts={"paramstyle": "named"},
+        compare_type=True,
+    )
+    with context.begin_transaction():
+        context.run_migrations()
+
+
+def do_run_migrations(connection):  # type: ignore[no-untyped-def]
+    context.configure(
+        connection=connection,
+        target_metadata=target_metadata,
+        compare_type=True,
+    )
+    with context.begin_transaction():
+        context.run_migrations()
+
+
+async def run_migrations_online_async() -> None:
+    """Run migrations against a live DB using the async engine."""
+    async_url = os.environ.get("DATABASE_URL", "")
+    if not async_url:
+        from app.config.settings import settings  # noqa: PLC0415
+        async_url = settings.DATABASE_URL
+
+    connectable = create_async_engine(async_url, poolclass=pool.NullPool)
+    async with connectable.connect() as connection:
+        await connection.run_sync(do_run_migrations)
+    await connectable.dispose()
+
+
+def run_migrations_online() -> None:
+    asyncio.run(run_migrations_online_async())
+
+
+if context.is_offline_mode():
+    run_migrations_offline()
+else:
+    run_migrations_online()