5518c95237
pool_size=5, max_overflow=10 per app (6 apps = 90 max connections). Previously pool_size=0 meant unlimited connections, causing asyncpg.TooManyConnectionsError under concurrent load. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
77 lines
2.0 KiB
Python
77 lines
2.0 KiB
Python
from __future__ import annotations
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import os
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from contextlib import asynccontextmanager
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from sqlalchemy.ext.asyncio import create_async_engine, async_sessionmaker, AsyncSession
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from quart import Quart, g
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DATABASE_URL = (
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os.getenv("DATABASE_URL_ASYNC")
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or os.getenv("DATABASE_URL")
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or "postgresql+asyncpg://localhost/blog"
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)
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_engine = create_async_engine(
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DATABASE_URL,
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future=True,
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echo=False,
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pool_pre_ping=True,
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pool_size=5,
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max_overflow=10,
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)
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_Session = async_sessionmaker(
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bind=_engine,
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class_=AsyncSession,
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expire_on_commit=False,
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)
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@asynccontextmanager
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async def get_session():
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"""Always create a fresh AsyncSession for this block."""
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sess = _Session()
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try:
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yield sess
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finally:
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await sess.close()
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def register_db(app: Quart):
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@app.before_request
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async def open_session():
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g.s = _Session()
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g.tx = await g.s.begin()
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g.had_error = False
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@app.after_request
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async def maybe_commit(response):
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# Runs BEFORE bytes are sent.
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if not g.had_error and 200 <= response.status_code < 400:
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try:
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if hasattr(g, "tx"):
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await g.tx.commit()
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except Exception as e:
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print(f'commit failed {e}')
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if hasattr(g, "tx"):
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await g.tx.rollback()
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from quart import make_response
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return await make_response("Commit failed", 500)
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return response
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@app.teardown_request
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async def finish(exc):
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try:
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# If an exception occurred OR we didn't commit (still in txn), roll back.
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if hasattr(g, "s"):
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if exc is not None or g.s.in_transaction():
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if hasattr(g, "tx"):
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await g.tx.rollback()
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finally:
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if hasattr(g, "s"):
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await g.s.close()
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@app.errorhandler(Exception)
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async def mark_error(e):
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g.had_error = True
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raise
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