upgrade flask-sqlalchemy to 2.5.1

[bertrandmartel]

After following the instructions in the Readme, I've built and run the docker image. Hitting the API gave me this error:

2021-06-22 12:28:20,643 ERROR app.py:1890 - Exception on /api/v1.0/captcha [GET]
Traceback (most recent call last):
  File "/usr/local/lib/python3.8/site-packages/sqlalchemy/util/_collections.py", line 1008, in __call__
    return self.registry[key]
KeyError: <greenlet.greenlet object at 0x7f84bfe7fca0 (otid=0x7f84c100d140) current active started main>

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/local/lib/python3.8/site-packages/flask/app.py", line 1949, in full_dispatch_request
    rv = self.dispatch_request()
  File "/usr/local/lib/python3.8/site-packages/flask/app.py", line 1935, in dispatch_request
    return self.view_functions[rule.endpoint](**req.view_args)
  File "/usr/local/lib/python3.8/site-packages/flask_restx/api.py", line 375, in wrapper
    resp = resource(*args, **kwargs)
  File "/usr/local/lib/python3.8/site-packages/flask/views.py", line 89, in view
    return self.dispatch_request(*args, **kwargs)
  File "/usr/local/lib/python3.8/site-packages/flask_restx/resource.py", line 44, in dispatch_request
    resp = meth(*args, **kwargs)
  File "/app/captcha_api/rest.py", line 62, in get
    db.session.add(new_captcha)
  File "<string>", line 2, in add
  File "/usr/local/lib/python3.8/site-packages/sqlalchemy/orm/scoping.py", line 105, in _proxied
    return self.registry()
  File "/usr/local/lib/python3.8/site-packages/sqlalchemy/util/_collections.py", line 1010, in __call__
    return self.registry.setdefault(key, self.createfunc())
  File "/usr/local/lib/python3.8/site-packages/sqlalchemy/orm/session.py", line 4101, in __call__
    return self.class_(**local_kw)
  File "/usr/local/lib/python3.8/site-packages/flask_sqlalchemy/__init__.py", line 138, in __init__
    bind = options.pop('bind', None) or db.engine
  File "/usr/local/lib/python3.8/site-packages/flask_sqlalchemy/__init__.py", line 943, in engine
    return self.get_engine()
  File "/usr/local/lib/python3.8/site-packages/flask_sqlalchemy/__init__.py", line 962, in get_engine
    return connector.get_engine()
  File "/usr/local/lib/python3.8/site-packages/flask_sqlalchemy/__init__.py", line 555, in get_engine
    options = self.get_options(sa_url, echo)
  File "/usr/local/lib/python3.8/site-packages/flask_sqlalchemy/__init__.py", line 570, in get_options
    self._sa.apply_driver_hacks(self._app, sa_url, options)
  File "/usr/local/lib/python3.8/site-packages/flask_sqlalchemy/__init__.py", line 914, in apply_driver_hacks
    sa_url.database = os.path.join(app.root_path, sa_url.database)
AttributeError: can't set attribute

I've found out this issue about sqlAlchemy. Upgrading flask-sqlalchemy to 2.5.1 fixes the error

[saibot94]

Hi, thanks for the contribution!

Looking at things running on our production deployment of the service, I see the following versions:

Flask-SQLAlchemy==2.4.4
SQLAlchemy==1.3.19

According to what you added and the suggestions in the linked issue, I think for now it's safer to just pin the SQLAlchemy version to 1.3.x and not upgrade the Flask-SQLAlchemy.

Could you try it and confirm it's working?

[saibot94]

Please check the comment on the PR.

[bertrandmartel]

@saibot94 Thanks, yes it works as you suggested

[saibot94]

Thanks a lot, merging it as such.