Set http status of spans in FastAPI integration

[antonpirker]

Problem Statement

The FastAPI (and Starlette) integrations should set the http status of the current span to the http status of the request. Nice information to have!

Solution Brainstorm

How @tiangolo does this:

class SentrySpanStatusMiddleware:
    """
    Currently Sentry doesn't automatically detect the span status, so manually set it here
    Ref: https://github.com/getsentry/sentry-python/blob/master/sentry_sdk/integrations/asgi.py#L147-L149
    This middleware has to be added *before* CustomSentryMiddleware so that it's called
    *inside* of it and the current span is available
    """

    def __init__(
        self,
        app: ASGIApp,
    ) -> None:
        self.app = app

    async def __call__(self, scope: Scope, receive: Receive, send: Send) -> None:
        if scope["type"] != "http":
            await self.app(scope, receive, send)
            return

        request = Request(scope, receive, send)
        sentry_trace = request.headers.get("custom-sentry-trace")
        if sentry_trace is not None:
            with sentry_sdk.configure_scope() as sentry_scope:
                sentry_scope.set_tag("trace_id", sentry_trace)

        async def send_wrapper(message: Message) -> None:
            if message["type"] == "http.response.start":
                span = sentry_sdk.Hub.current.scope.span
                if span:
                    span.set_http_status(message["status"])
            await send(message)

        return await self.app(scope, receive, send_wrapper)