Gitlab auth plugin is not recognized after update from 9.1.2

Hi all,

I am upgrading our onpremise Sentry version from 9.1.2 to the latest 20.10.1. For authentication we are using the gitlab-auth plugin (https://github.com/SkyLothar/sentry-auth-gitlab). As it turns out, that plugin is no longer compatible with the updates to Sentry, I found a fork that should work according to its author (https://github.com/cirmaciu/sentry-auth-gitlab). Unfortunately, it does not.

When I access our Sentry environment, it shows an error page, and the logs state:

web_1                          | Traceback (most recent call last):
web_1                          |   File "/usr/local/lib/python2.7/site-packages/django/core/handlers/exception.py", line 41, in inner
web_1                          |     response = get_response(request)
web_1                          |   File "/usr/local/lib/python2.7/site-packages/django/core/handlers/base.py", line 249, in _legacy_get_response
web_1                          |     response = self._get_response(request)
web_1                          |   File "/usr/local/lib/python2.7/site-packages/django/core/handlers/base.py", line 187, in _get_response
web_1                          |     response = self.process_exception_by_middleware(e, request)
web_1                          |   File "/usr/local/lib/python2.7/site-packages/django/core/handlers/base.py", line 185, in _get_response
web_1                          |     response = wrapped_callback(request, *callback_args, **callback_kwargs)
web_1                          |   File "/usr/local/lib/python2.7/site-packages/sentry_sdk/integrations/django/views.py", line 63, in callback
web_1                          |     return old_callback(*args, **kwargs)
web_1                          |   File "/usr/local/lib/python2.7/site-packages/sentry_sdk/integrations/django/views.py", line 63, in callback
web_1                          |     return old_callback(*args, **kwargs)
web_1                          |   File "/usr/local/lib/python2.7/site-packages/django/views/generic/base.py", line 68, in view
web_1                          |     return self.dispatch(request, *args, **kwargs)
web_1                          |   File "/usr/local/lib/python2.7/site-packages/django/views/decorators/csrf.py", line 58, in wrapped_view
web_1                          |     return view_func(*args, **kwargs)
web_1                          |   File "/usr/local/lib/python2.7/site-packages/sentry/web/frontend/base.py", line 227, in dispatch
web_1                          |     return self.handle(request, *args, **kwargs)
web_1                          |   File "/usr/local/lib/python2.7/site-packages/django/views/decorators/cache.py", line 57, in _wrapped_view_func
web_1                          |     response = view_func(request, *args, **kwargs)
web_1                          |   File "/usr/local/lib/python2.7/site-packages/django/utils/decorators.py", line 185, in inner
web_1                          |     return func(*args, **kwargs)
web_1                          |   File "/usr/local/lib/python2.7/site-packages/sentry/web/frontend/auth_organization_login.py", line 72, in handle
web_1                          |     response = self.handle_sso(request, organization, auth_provider)
web_1                          |   File "/usr/local/lib/python2.7/site-packages/sentry/web/frontend/auth_organization_login.py", line 35, in handle_sso
web_1                          |     provider = auth_provider.get_provider()
web_1                          |   File "/usr/local/lib/python2.7/site-packages/sentry/models/authprovider.py", line 51, in get_provider
web_1                          |     return manager.get(self.provider, **self.config)
web_1                          |   File "/usr/local/lib/python2.7/site-packages/sentry/auth/manager.py", line 23, in get
web_1                          |     raise ProviderNotRegistered(key)
web_1                          | ProviderNotRegistered: gitlab
web_1                          | 13:44:29 [ERROR] django.request: Internal Server Error: /auth/login/triple/ (status_code=500 request=<WSGIRequest: GET u'/auth/login/triple/'>)

I know/understand that it is not officially supported here, but could anyone here have a look at it and help me with one of the following items:

  1. Get the gitlab plugin to work again
  2. Or, if that is not possible, how can I make our Sentry not redirect to the SSO page, but instead require manual login again.
  3. Our company also has Azure AD available to login with, can I instead configure that as an SSO provider? And how?