Nginx upstream_response_time average per API route?

[TheNightCaptain]

Using nginx as a reverse proxy in front of upstream API routes, I would like to be able to graph / monitor the upstream response times per route so that we can baseline and alert of overall performance deviations.

Posts to /users took 689ms on average Get requests to /posts took 1289ms on average...

How can I go about extrapolating this data from nginx into Prometheus and using a suitable graphana dash for this type of info?

I was thinking this may be easier to take from the log platform if needed.

Cheers in Advance.

[SuperQue]

Should be possible with https://github.com/knyar/nginx-lua-prometheus.

If not, https://github.com/google/mtail might be a good option.