Refactor Sanic integration for v21.9 support

[ahopkins]

This PR allows for Sanic v21.9 style error handlers to operate and provide full access to handling Blueprint specific error handlers.

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The ErrorHandler.lookup now requires two positional arguments:

Source

See also: sanic-org/sanic#2259

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UPDATE:
Fixes #1240
Fixes sanic-org/sanic#2250

[ahopkins]

@AbhiPrasad So, I think this is generally a better approach. It will avoid touching handle_request which is really not a safe method to be monkeypatching.

Instead, we monkeypatch the _startup method to inject some code into the request cycle using signals. You do not need to familiarize yourself too much with them other than to know it is a method to inject arbitrary code into the request/response cycle at predetermined points.

Locally all of the tests pass, except for test_concurrency. I think before I dig too deep into this to figure out why, it might be helpful if I understood some of this stuff:

    weak_request = weakref.ref(request)
    request.ctx._sentry_hub = Hub(hub)
    request.ctx._sentry_hub.__enter__()

    with request.ctx._sentry_hub.configure_scope() as scope:
        scope.clear_breadcrumbs()
        scope.add_event_processor(_make_request_processor(weak_request))

        with capture_internal_exceptions():
            with hub.configure_scope() as scope:

Also, what is the scope and the assert in this handler trying to achieve?

    @app.route("/context-check/<i>")
    async def context_check(request, i):
        with configure_scope() as scope:
            scope.set_tag("i", i)

        await asyncio.sleep(random.random())

        with configure_scope() as scope:
            assert scope._tags["i"] == i

        return response.text("ok")

Any insight you could share?

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UPDATE: Nevermind... I figured it out. I just pushed another commit now where I believe all tests 🤞 should pass (they do locally 😆 )

I ran it using 21.9, 21.6, 21.3, 20.12 ✔️

[rhcarvalho]

Thanks for the PR.

We have tried to focus on LTS versions as documented in https://docs.sentry.io/platforms/python/guides/sanic/.
We did merge in contributions to support recent non-LTS versions, but that's coming with a maintenance cost.

I'm happy we take this in to unblock users, but would also like to strongly consider dropping support for the non-LTS releases once 21.12 is out. Would that be a fair ask?

[rhcarvalho]

For maintainability and testability, I'd avoid global state and make this an instance attribute of SanicIntegration.

[ahopkins]

Are you okay with it being a class attribute?

[ahopkins]

I'm happy we take this in to unblock users, but would also like to strongly consider dropping support for the non-LTS releases once 21.12 is out. Would that be a fair ask?

That is a contract between you and your user base. I'm happy to make this PR to help out and/or be a resource as needed.

[AbhiPrasad]

Thank you for your contribution @ahopkins!