Feature preview: Custom metrics

Thanks Jerome, no pressure. I’m building up a dashboard and wanted to add a gauge to expose volume info. Happy to contribute it back.

Since I have your attention two more related questions:

  1. You are exposing a proxy_id label with values green and blue. What does this mean?

  2. What does fly_app_concurrency represent?

proxy_id - is to make sure the counters reset when we deploy or else it leads to some weird metrics. It’s possible we can have 2 proxies running concurrently while we gracefully shut down connections during a deploy.

fly_app_concurrency - this is the current number of connections (or requests, depending on your concurrency config) established to your app instance

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Last question (I hope) related to metrics, does fly-cache-status Cache Hits in Metrics require the HTTP handler, or does it work regardless? I have a custom cache status header i can change, would allow me to easily expose a cache hit ratio in Grafana.

It does require the HTTP handler, we don’t parse HTTP responses headers when the handler isn’t setup.

I’ve done some work on the volume metrics. Today I’m going to do some more and try to resolve this situation!

@johan volume metrics should now be back.

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Thanks @jerome. Works great.

Edit: I have two apps, one staging single instance and one production with 2 instances. I"m getting fly_volume_used_pct data for the single instance app, not for the multi instance app. Query is basic:


max by(region) (fly_volume_used_pct{app=~"jt-web-staging", region=~".*", host=~".*"})


max by(region) (fly_volume_used_pct{app=~"jt-web-production", region=~".*", host=~".*"})

Any ideas?

@jerome Not sure if you saw the edit to my reply. Just a quick nudge just in case.