RuntimeError: unable to perform operation

[BenGeba]

Hello,
I don't know if this belongs here and if not, you are welcome to close it again.
I'm using the Spoolman app and keep getting an error message from time to time. Since uvicorn seems to be the last place that is called in the error message, I thought you might be able to help so that I can inform the creator of the app.
The error message looks like this:

INFO:     192.168.178.77:38644 - "GET /api/v1/spool?allow_archived=False HTTP/1.1" 500 Internal Server Error
ERROR:    Exception in ASGI application
Traceback (most recent call last):
  File "/home/app/spoolman/.venv/lib/python3.11/site-packages/uvicorn/protocols/http/httptools_impl.py", line 411, in run_asgi
    result = await app(  # type: ignore[func-returns-value]
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/app/spoolman/.venv/lib/python3.11/site-packages/uvicorn/middleware/proxy_headers.py", line 69, in __call__
    return await self.app(scope, receive, send)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/app/spoolman/.venv/lib/python3.11/site-packages/fastapi/applications.py", line 1054, in __call__
    await super().__call__(scope, receive, send)
  File "/home/app/spoolman/.venv/lib/python3.11/site-packages/starlette/applications.py", line 123, in __call__
    await self.middleware_stack(scope, receive, send)
  File "/home/app/spoolman/.venv/lib/python3.11/site-packages/starlette/middleware/errors.py", line 186, in __call__
    raise exc
  File "/home/app/spoolman/.venv/lib/python3.11/site-packages/starlette/middleware/errors.py", line 164, in __call__
    await self.app(scope, receive, _send)
  File "/home/app/spoolman/.venv/lib/python3.11/site-packages/starlette/middleware/gzip.py", line 24, in __call__
    await responder(scope, receive, send)
  File "/home/app/spoolman/.venv/lib/python3.11/site-packages/starlette/middleware/gzip.py", line 44, in __call__
    await self.app(scope, receive, self.send_with_gzip)
  File "/home/app/spoolman/.venv/lib/python3.11/site-packages/starlette/middleware/exceptions.py", line 65, in __call__
    await wrap_app_handling_exceptions(self.app, conn)(scope, receive, send)
  File "/home/app/spoolman/.venv/lib/python3.11/site-packages/starlette/_exception_handler.py", line 64, in wrapped_app
    raise exc
  File "/home/app/spoolman/.venv/lib/python3.11/site-packages/starlette/_exception_handler.py", line 53, in wrapped_app
    await app(scope, receive, sender)
  File "/home/app/spoolman/.venv/lib/python3.11/site-packages/starlette/routing.py", line 756, in __call__
    await self.middleware_stack(scope, receive, send)
  File "/home/app/spoolman/.venv/lib/python3.11/site-packages/starlette/routing.py", line 776, in app
    await route.handle(scope, receive, send)
  File "/home/app/spoolman/.venv/lib/python3.11/site-packages/starlette/routing.py", line 485, in handle
    await self.app(scope, receive, send)
  File "/home/app/spoolman/.venv/lib/python3.11/site-packages/fastapi/applications.py", line 1054, in __call__
    await super().__call__(scope, receive, send)
  File "/home/app/spoolman/.venv/lib/python3.11/site-packages/starlette/applications.py", line 123, in __call__
    await self.middleware_stack(scope, receive, send)
  File "/home/app/spoolman/.venv/lib/python3.11/site-packages/starlette/middleware/errors.py", line 186, in __call__
    raise exc
  File "/home/app/spoolman/.venv/lib/python3.11/site-packages/starlette/middleware/errors.py", line 164, in __call__
    await self.app(scope, receive, _send)
  File "/home/app/spoolman/.venv/lib/python3.11/site-packages/starlette/middleware/exceptions.py", line 65, in __call__
    await wrap_app_handling_exceptions(self.app, conn)(scope, receive, send)
  File "/home/app/spoolman/.venv/lib/python3.11/site-packages/starlette/_exception_handler.py", line 64, in wrapped_app
    raise exc
  File "/home/app/spoolman/.venv/lib/python3.11/site-packages/starlette/_exception_handler.py", line 53, in wrapped_app
    await app(scope, receive, sender)
  File "/home/app/spoolman/.venv/lib/python3.11/site-packages/starlette/routing.py", line 756, in __call__
    await self.middleware_stack(scope, receive, send)
  File "/home/app/spoolman/.venv/lib/python3.11/site-packages/starlette/routing.py", line 776, in app
    await route.handle(scope, receive, send)
  File "/home/app/spoolman/.venv/lib/python3.11/site-packages/starlette/routing.py", line 297, in handle
    await self.app(scope, receive, send)
  File "/home/app/spoolman/.venv/lib/python3.11/site-packages/starlette/routing.py", line 77, in app
    await wrap_app_handling_exceptions(app, request)(scope, receive, send)
  File "/home/app/spoolman/.venv/lib/python3.11/site-packages/starlette/_exception_handler.py", line 64, in wrapped_app
    raise exc
  File "/home/app/spoolman/.venv/lib/python3.11/site-packages/starlette/_exception_handler.py", line 53, in wrapped_app
    await app(scope, receive, sender)
  File "/home/app/spoolman/.venv/lib/python3.11/site-packages/starlette/routing.py", line 72, in app
    response = await func(request)
               ^^^^^^^^^^^^^^^^^^^
  File "/home/app/spoolman/.venv/lib/python3.11/site-packages/fastapi/routing.py", line 278, in app
    raw_response = await run_endpoint_function(
                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/app/spoolman/.venv/lib/python3.11/site-packages/fastapi/routing.py", line 191, in run_endpoint_function
    return await dependant.call(**values)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/app/spoolman/spoolman/api/v1/spool.py", line 277, in find
    db_items, total_count = await spool.find(
                            ^^^^^^^^^^^^^^^^^
  File "/home/app/spoolman/spoolman/database/spool.py", line 201, in find
    rows = await db.execute(stmt)
           ^^^^^^^^^^^^^^^^^^^^^^
  File "/home/app/spoolman/.venv/lib/python3.11/site-packages/sqlalchemy/ext/asyncio/session.py", line 461, in execute
    result = await greenlet_spawn(
             ^^^^^^^^^^^^^^^^^^^^^
  File "/home/app/spoolman/.venv/lib/python3.11/site-packages/sqlalchemy/util/_concurrency_py3k.py", line 201, in greenlet_spawn
    result = context.throw(*sys.exc_info())
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/app/spoolman/.venv/lib/python3.11/site-packages/sqlalchemy/orm/session.py", line 2351, in execute
    return self._execute_internal(
           ^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/app/spoolman/.venv/lib/python3.11/site-packages/sqlalchemy/orm/session.py", line 2226, in _execute_internal
    conn = self._connection_for_bind(bind)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/app/spoolman/.venv/lib/python3.11/site-packages/sqlalchemy/orm/session.py", line 2095, in _connection_for_bind
    return trans._connection_for_bind(engine, execution_options)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "<string>", line 2, in _connection_for_bind
  File "/home/app/spoolman/.venv/lib/python3.11/site-packages/sqlalchemy/orm/state_changes.py", line 139, in _go
    ret_value = fn(self, *arg, **kw)
                ^^^^^^^^^^^^^^^^^^^^
  File "/home/app/spoolman/.venv/lib/python3.11/site-packages/sqlalchemy/orm/session.py", line 1189, in _connection_for_bind
    conn = bind.connect()
           ^^^^^^^^^^^^^^
  File "/home/app/spoolman/.venv/lib/python3.11/site-packages/sqlalchemy/engine/base.py", line 3276, in connect
    return self._connection_cls(self)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/app/spoolman/.venv/lib/python3.11/site-packages/sqlalchemy/engine/base.py", line 146, in __init__
    self._dbapi_connection = engine.raw_connection()
                             ^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/app/spoolman/.venv/lib/python3.11/site-packages/sqlalchemy/engine/base.py", line 3300, in raw_connection
    return self.pool.connect()
           ^^^^^^^^^^^^^^^^^^^
  File "/home/app/spoolman/.venv/lib/python3.11/site-packages/sqlalchemy/pool/base.py", line 449, in connect
    return _ConnectionFairy._checkout(self)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/app/spoolman/.venv/lib/python3.11/site-packages/sqlalchemy/pool/base.py", line 1362, in _checkout
    with util.safe_reraise():
  File "/home/app/spoolman/.venv/lib/python3.11/site-packages/sqlalchemy/util/langhelpers.py", line 146, in __exit__
    raise exc_value.with_traceback(exc_tb)
  File "/home/app/spoolman/.venv/lib/python3.11/site-packages/sqlalchemy/pool/base.py", line 1300, in _checkout
    result = pool._dialect._do_ping_w_event(
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/app/spoolman/.venv/lib/python3.11/site-packages/sqlalchemy/engine/default.py", line 715, in _do_ping_w_event
    return self.do_ping(dbapi_connection)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/app/spoolman/.venv/lib/python3.11/site-packages/sqlalchemy/dialects/mysql/pymysql.py", line 107, in do_ping
    dbapi_connection.ping(False)
  File "/home/app/spoolman/.venv/lib/python3.11/site-packages/sqlalchemy/dialects/mysql/aiomysql.py", line 186, in ping
    return self.await_(self._connection.ping(reconnect))
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/app/spoolman/.venv/lib/python3.11/site-packages/sqlalchemy/util/_concurrency_py3k.py", line 132, in await_only
    return current.parent.switch(awaitable)  # type: ignore[no-any-return,attr-defined] # noqa: E501
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/app/spoolman/.venv/lib/python3.11/site-packages/sqlalchemy/util/_concurrency_py3k.py", line 196, in greenlet_spawn
    value = await result
            ^^^^^^^^^^^^
  File "/home/app/spoolman/.venv/lib/python3.11/site-packages/aiomysql/connection.py", line 493, in ping
    await self._execute_command(COMMAND.COM_PING, "")
  File "/home/app/spoolman/.venv/lib/python3.11/site-packages/aiomysql/connection.py", line 724, in _execute_command
    self._write_bytes(prelude + sql[:chunk_size - 1])
  File "/home/app/spoolman/.venv/lib/python3.11/site-packages/aiomysql/connection.py", line 669, in _write_bytes
    return self._writer.write(data)
           ^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.11/asyncio/streams.py", line 332, in write
    self._transport.write(data)
  File "uvloop/handles/stream.pyx", line 674, in uvloop.loop.UVStream.write
  File "uvloop/handles/handle.pyx", line 159, in uvloop.loop.UVHandle._ensure_alive
RuntimeError: unable to perform operation on <TCPTransport closed=True reading=False 0x298f820>; the handler is closed

[theyashl]

From traceback looks like the issue is with your DB connection. Nothing specific to uvicorn.
your rows = await db.execute(stmt) line is being failed since the connection with database is broken.