Incorrect http_requests_total with multiple Middleware about prometheus-fastapi-instrumentator

[shrinusivakumar]

@rajeshdhanda I'm experiencing the same issue. It seems that the issue is known. Check out the comment in main.py:

    # Starlette will call app.build_middleware_stack() with every new middleware
    # added, which will call all this again, which will make the registry
    # complain about duplicated metrics.
    #
    # The Python Prometheus client currently doesn't seem to have a way to
    # verify if adding a metric will cause errors or not, so the only way to
    # handle it seems to be with this try block.

If I'm reading this right, then it looks like each middleware will call to add each metric. Adding the first instance of the metrics should be fine. The subsequent calls from each middleware should raise an exception, but I think that exception is not happening in our case. Will continue to dig.

[IceRiverDev]

Hi guys, I also have a question about the http_requests_total. As i understanding, this metric is a counter and the value should always increase, but when i execute query http_requests_total in prometheus dashboard, the graph is like below:

Is the graph normal or not? For my perception the line should always have an increasing trend instead of decreasing.

[Fulmo]

Hi folks, does someone have solution for this? I'm observing the same issue