Connection Error - peewee.InterfaceError: (0, '')
Sorry, I'm not familiar with fastapi but presumably it's something to do with sharing connections across threads or processes or some other asyncio-related issue.
Hi,

I using FastAPI with Peewee and PyMySQL and get the following Error:

`[2021-04-07 09:56:38 +0000] [729] [ERROR] Exception in ASGI application
Traceback (most recent call last):
  File "/usr/local/lib/python3.8/site-packages/uvicorn/protocols/http/httptools_impl.py", line 398, in run_asgi
    result = await app(self.scope, self.receive, self.send)
  File "/usr/local/lib/python3.8/site-packages/uvicorn/middleware/proxy_headers.py", line 45, in __call__
    return await self.app(scope, receive, send)
  File "/usr/local/lib/python3.8/site-packages/fastapi/applications.py", line 199, in __call__
    await super().__call__(scope, receive, send)
  File "/usr/local/lib/python3.8/site-packages/starlette/applications.py", line 111, in __call__
    await self.middleware_stack(scope, receive, send)
  File "/usr/local/lib/python3.8/site-packages/starlette/middleware/errors.py", line 181, in __call__
    raise exc from None
  File "/usr/local/lib/python3.8/site-packages/starlette/middleware/errors.py", line 159, in __call__
    await self.app(scope, receive, _send)
  File "/usr/local/lib/python3.8/site-packages/starlette/middleware/cors.py", line 78, in __call__
    await self.app(scope, receive, send)
  File "/usr/local/lib/python3.8/site-packages/starlette/exceptions.py", line 82, in __call__
    raise exc from None
  File "/usr/local/lib/python3.8/site-packages/starlette/exceptions.py", line 71, in __call__
    await self.app(scope, receive, sender)
  File "/usr/local/lib/python3.8/site-packages/starlette/routing.py", line 566, in __call__
    await route.handle(scope, receive, send)
  File "/usr/local/lib/python3.8/site-packages/starlette/routing.py", line 227, in handle
    await self.app(scope, receive, send)
  File "/usr/local/lib/python3.8/site-packages/starlette/routing.py", line 41, in app
    response = await func(request)
  File "/usr/local/lib/python3.8/site-packages/fastapi/routing.py", line 201, in app
    raw_response = await run_endpoint_function(
  File "/usr/local/lib/python3.8/site-packages/fastapi/routing.py", line 148, in run_endpoint_function
    return await dependant.call(**values)
  File "/app/main.py", line 257, in get_cat
    cursor = DB.execute_sql('''SELECT *
  File "/usr/local/lib/python3.8/site-packages/peewee.py", line 3151, in execute_sql
    self.commit()
  File "/usr/local/lib/python3.8/site-packages/peewee.py", line 2917, in __exit__
    reraise(new_type, new_type(exc_value, *exc_args), traceback)
  File "/usr/local/lib/python3.8/site-packages/peewee.py", line 190, in reraise
    raise value.with_traceback(tb)
  File "/usr/local/lib/python3.8/site-packages/peewee.py", line 3144, in execute_sql
    cursor.execute(sql, params or ())
  File "/usr/local/lib/python3.8/site-packages/pymysql/cursors.py", line 148, in execute
    result = self._query(query)
  File "/usr/local/lib/python3.8/site-packages/pymysql/cursors.py", line 310, in _query
    conn.query(q)
  File "/usr/local/lib/python3.8/site-packages/pymysql/connections.py", line 547, in query
    self._execute_command(COMMAND.COM_QUERY, sql)
  File "/usr/local/lib/python3.8/site-packages/pymysql/connections.py", line 793, in _execute_command
    raise err.InterfaceError(0, "")
peewee.InterfaceError: (0, '')`

I have searched for this problem, but nothing helps.

I inserted these in my Code, but it doesnt work:
`    if DB.is_closed():
        DB.connect()`

Best Regards