Update Documentation

[justinreddick]

Greetings,

I copied and ran the @inprogress decorator example, and when viewing the metrics endpoint, I observed the metric did not increment. It stayed at 1

# HELP request_in_progress Number of requests in progress
# TYPE request_in_progress gauge
request_in_progress{route="/"} 1
# HELP request_total Total number of requests
# TYPE request_total counter
request_total{route="/"} 338

Using python 3.9.11, using this requirements.in:

aioprometheus[aiohttp,starlette,quart]
asgiref
gunicorn
icmplib
orjson
pbr
psutil
starlette
twine
ujson
uvicorn[standard]
wheel

[claws]

The request_in_progress is likely to always be 1 if you run the demo script as the script is the only client accessing routes that trigger metrics updates and it is only perfroming one request at a time. This is due to the simplicity of the example script. You can see from the request_total metric that the route had been accessed 338 times, so the script was working.

If you wanted to increase the likelihood of seeing multiple requests being in-progress you could modify the script to perform two fetches. Something like this:

async def handle_requests():
    # Start up the server to expose the metrics.
    await svr.start(port=8000)
    # Generate some requests.
    while True:
        # Perform two requests to increase likelihood of observing two
        # requests in progress when fetching metrics.
        await asyncio.gather(
            handle_request(random.random()),
            handle_request(random.random()),
        )

If I run the curl command repeatedly to fetch metrics I occasionally see 2 requests in progress, like this:

(aioprom) $ curl http://127.0.0.1:8000/metrics
# HELP request_in_progress Number of requests in progress
# TYPE request_in_progress gauge
request_in_progress{route="/"} 2
# HELP request_total Total number of requests
# TYPE request_total counter
request_total{route="/"} 30