【发布时间】：2021-01-04 16:24:16
【问题描述】：
我正在尝试使用 SQL Alchemy 和 docker-compose 将用户添加到 PSQL DB。我有 2 个容器：“db”和“py”。构建并运行容器后，我点击“py”容器中的 API 来存储用户。当我运行db_session.commit() 来保存用户时，我收到以下错误：
RecursionError: 超出最大递归深度
当我在本地运行此代码时，它可以完美运行。我将数据库主机更改为localhost，并且用户已正确存储在数据库中。在 docker 容器中运行时，出现递归错误。
db/handler.py
@contextmanager
def session_scope():
engine = create_engine('postgresql+psycopg2://postgres:postgres@db:5432/my_db', echo=True)
session_factory = sessionmaker(bind=engine)
db_session = scoped_session(session_factory)
try:
yield db_session
except:
db_session.rollback()
finally:
db_session.close()
docker-compose.yaml
services:
py01:
build: ./py
image: py
depends_on:
- db
container_name: py
expose:
- 8000
db01:
build: ./db
image: db
container_name: db
ports:
- "5432:5432"
users.py
with session_scope() as db_session:
user = User(user_class="tempweb", temp_web_id=temp_web_id)
db_session.add(user)
db_session.commit() # <---- MAXIMUM RECURSION DEPTH EXCEEDED error occurs here
堆栈回溯
py | ERROR: Exception in ASGI application
py | Traceback (most recent call last):
py | File "/opt/pypy/site-packages/uvicorn/protocols/http/h11_impl.py", line 388, in run_asgi
py | result = await app(self.scope, self.receive, self.send)
py | File "/opt/pypy/site-packages/uvicorn/middleware/proxy_headers.py", line 45, in __call__
py | return await self.app(scope, receive, send)
py | File "/opt/pypy/site-packages/fastapi/applications.py", line 182, in __call__
py | await super().__call__(scope, receive, send) # pragma: no cover
py | File "/opt/pypy/site-packages/starlette/applications.py", line 111, in __call__
py | await self.middleware_stack(scope, receive, send)
py | File "/opt/pypy/site-packages/starlette/middleware/errors.py", line 181, in __call__
py | raise exc from None
py | File "/opt/pypy/site-packages/starlette/middleware/errors.py", line 159, in __call__
py | await self.app(scope, receive, _send)
py | File "/opt/pypy/site-packages/starlette/middleware/cors.py", line 78, in __call__
py | await self.app(scope, receive, send)
py | File "/opt/pypy/site-packages/starlette/exceptions.py", line 82, in __call__
py | raise exc from None
py | File "/opt/pypy/site-packages/starlette/exceptions.py", line 71, in __call__
py | await self.app(scope, receive, sender)
py | File "/opt/pypy/site-packages/starlette/routing.py", line 566, in __call__
py | await route.handle(scope, receive, send)
py | File "/opt/pypy/site-packages/starlette/routing.py", line 227, in handle
py | await self.app(scope, receive, send)
py | File "/opt/pypy/site-packages/starlette/routing.py", line 41, in app
py | response = await func(request)
py | File "/opt/pypy/site-packages/fastapi/routing.py", line 197, in app
py | dependant=dependant, values=values, is_coroutine=is_coroutine
py | File "/opt/pypy/site-packages/fastapi/routing.py", line 149, in run_endpoint_function
py | return await run_in_threadpool(dependant.call, **values)
py | File "/opt/pypy/site-packages/starlette/concurrency.py", line 34, in run_in_threadpool
py | return await loop.run_in_executor(None, func, *args)
py | File "/opt/pypy/lib-python/3/asyncio/futures.py", line 327, in __iter__
py | yield self # This tells Task to wait for completion.
py | File "/opt/pypy/lib-python/3/asyncio/tasks.py", line 250, in _wakeup
py | future.result()
py | File "/opt/pypy/lib-python/3/asyncio/futures.py", line 243, in result
py | raise self._exception
py | File "/opt/pypy/lib-python/3/concurrent/futures/thread.py", line 56, in run
py | result = self.fn(*self.args, **self.kwargs)
py | File "./app/routers/users.py", line 33, in get_session
py | with session_scope() as db_session:
py | File "/opt/pypy/lib-python/3/contextlib.py", line 81, in __enter__
py | return next(self.gen)
py | File "./app/db/handler.py", line 10, in session_scope
py | engine.connect()
py | File "/opt/pypy/site-packages/sqlalchemy/engine/base.py", line 2265, in connect
py | return self._connection_cls(self, **kwargs)
py | File "/opt/pypy/site-packages/sqlalchemy/engine/base.py", line 104, in __init__
py | else engine.raw_connection()
py | File "/opt/pypy/site-packages/sqlalchemy/engine/base.py", line 2372, in raw_connection
py | self.pool.unique_connection, _connection
py | File "/opt/pypy/site-packages/sqlalchemy/engine/base.py", line 2338, in _wrap_pool_connect
py | return fn()
py | File "/opt/pypy/site-packages/sqlalchemy/pool/base.py", line 304, in unique_connection
py | return _ConnectionFairy._checkout(self)
py | File "/opt/pypy/site-packages/sqlalchemy/pool/base.py", line 778, in _checkout
py | fairy = _ConnectionRecord.checkout(pool)
py | File "/opt/pypy/site-packages/sqlalchemy/pool/base.py", line 495, in checkout
py | rec = pool._do_get()
py | File "/opt/pypy/site-packages/sqlalchemy/pool/impl.py", line 140, in _do_get
py | self._dec_overflow()
py | File "/opt/pypy/site-packages/sqlalchemy/util/langhelpers.py", line 69, in __exit__
py | exc_value, with_traceback=exc_tb,
py | File "/opt/pypy/site-packages/sqlalchemy/util/compat.py", line 182, in raise_
py | raise exception
py | File "/opt/pypy/site-packages/sqlalchemy/pool/impl.py", line 137, in _do_get
py | return self._create_connection()
py | File "/opt/pypy/site-packages/sqlalchemy/pool/base.py", line 309, in _create_connection
py | return _ConnectionRecord(self)
py | File "/opt/pypy/site-packages/sqlalchemy/pool/base.py", line 440, in __init__
py | self.__connect(first_connect_check=True)
py | File "/opt/pypy/site-packages/sqlalchemy/pool/base.py", line 666, in __connect
py | ).exec_once_unless_exception(self.connection, self)
py | File "/opt/pypy/site-packages/sqlalchemy/event/attr.py", line 314, in exec_once_unless_exception
py | self._exec_once_impl(True, *args, **kw)
py | File "/opt/pypy/site-packages/sqlalchemy/event/attr.py", line 285, in _exec_once_impl
py | self(*args, **kw)
py | File "/opt/pypy/site-packages/sqlalchemy/event/attr.py", line 322, in __call__
py | fn(*args, **kw)
py | File "/opt/pypy/site-packages/sqlalchemy/util/langhelpers.py", line 1513, in go
py | return once_fn(*arg, **kw)
py | File "/opt/pypy/site-packages/sqlalchemy/engine/strategies.py", line 199, in first_connect
py | dialect.initialize(c)
py | File "/opt/pypy/site-packages/sqlalchemy/dialects/postgresql/psycopg2.py", line 732, in initialize
py | super(PGDialect_psycopg2, self).initialize(connection)
py | File "/opt/pypy/site-packages/sqlalchemy/dialects/postgresql/base.py", line 2562, in initialize
py | super(PGDialect, self).initialize(connection)
py | File "/opt/pypy/site-packages/sqlalchemy/engine/default.py", line 313, in initialize
py | connection
py | File "/opt/pypy/site-packages/sqlalchemy/dialects/postgresql/base.py", line 2803, in _get_server_version_info
py | v = connection.execute("select version()").scalar()
py | File "/opt/pypy/site-packages/sqlalchemy/engine/base.py", line 1003, in execute
py | return self._execute_text(object_, multiparams, params)
py | File "/opt/pypy/site-packages/sqlalchemy/engine/base.py", line 1178, in _execute_text
py | parameters,
py | File "/opt/pypy/site-packages/sqlalchemy/engine/base.py", line 1317, in _execute_context
py | e, statement, parameters, cursor, context
py | File "/opt/pypy/site-packages/sqlalchemy/engine/base.py", line 1514, in _handle_dbapi_exception
py | util.raise_(exc_info[1], with_traceback=exc_info[2])
py | File "/opt/pypy/site-packages/sqlalchemy/util/compat.py", line 182, in raise_
py | raise exception
py | File "/opt/pypy/site-packages/sqlalchemy/engine/base.py", line 1294, in _execute_context
py | result = context._setup_crud_result_proxy()
py | File "/opt/pypy/site-packages/sqlalchemy/engine/default.py", line 1243, in _setup_crud_result_proxy
py | result = self.get_result_proxy()
py | File "/opt/pypy/site-packages/sqlalchemy/dialects/postgresql/psycopg2.py", line 601, in get_result_proxy
py | return _result.ResultProxy(self)
py | File "/opt/pypy/site-packages/sqlalchemy/engine/result.py", line 775, in __init__
py | self._init_metadata()
py | File "/opt/pypy/site-packages/sqlalchemy/engine/result.py", line 807, in _init_metadata
py | self._metadata = ResultMetaData(self, cursor_description)
py | File "/opt/pypy/site-packages/sqlalchemy/engine/result.py", line 296, in __init__
py | textual_ordered,
py | File "/opt/pypy/site-packages/sqlalchemy/engine/result.py", line 514, in _merge_cursor_description
py | ) in raw_iterator
py | File "/opt/pypy/site-packages/sqlalchemy/engine/result.py", line 497, in <listcomp>
py | (
py | File "/opt/pypy/site-packages/sqlalchemy/engine/result.py", line 621, in _merge_cols_by_none
py | ) in self._colnames_from_description(context, cursor_description):
py | File "/opt/pypy/site-packages/sqlalchemy/engine/result.py", line 541, in _colnames_from_description
py | colname = rec[0]
py | RecursionError: maximum recursion depth exceeded
【问题讨论】：
-
您检查过任何循环依赖问题吗？
-
@onlinejudge95 - 代码在本地运行时完美运行。是否存在仅在 docker 容器中运行时才会发生的循环依赖？
-
您的数据库架构中可能有循环引用。另外，我没有看到您在 Dockerfile 中运行迁移，您是否处理过这个问题？
标签： python postgresql docker-compose sqlalchemy