search

free / prometheus

The Prometheus monitoring system and time series database.
https://prometheus.io/
Apache License 2.0
48 stars 5 forks source link

promql/functions: Provide an option to replace rate extrapolation fun… #3

Closed jgracenin closed 6 years ago

jgracenin commented 6 years ago

This change adds an option to replace the rate & friends functions outright with xrate & friends functions. It allows for a drop-in replacement to disable rate extrapolation without needing to change dashboards, recording rules, alerts, etc. This should also keep the ecosystem working: Grafana auto-complete, tooling, Thanos, etc.

I decided to use an env var since the kingpin flags aren't global and this should be easier to merge over time (otherwise we'd need to change main.go). I also figured it makes sense to remove the xrate keys if using this mode instead of having both sets.

Tested locally and ran queries too: $ REPLACE_RATE_FUNCS=1 ./prometheus Successfully replaced rate & friends with xrate & friends (and removed xrate & friends function keys). level=info ts=2018-06-15T00:34:27.021727565Z caller=main.go:222 msg="Starting Prometheus" ...

jgracenin commented 6 years ago

Hi Alin,

Thanks again for xrate. It is used everyday extensively on millions of series (and recording/alert rules) -- I haven't seen any problems yet.

This is the code I'm always adding on top of your fork, so I figured it may be useful for someone else that wants to just turn off rate extrapolation without changing anything else.

Let me know if you want to make it a flag instead of an env var. I just figured that would be more painful to remember over time.

free commented 6 years ago

I was going to object that this muddies the waters and will make it more difficult to integrate the patch into Prometheus (which I still hope will eventually happen). But seeing how well contained it is, that's not really a good argument.

So yeah, LGTM, but this needs to be merged into the xrate branch, as master doesn't have the xrate functions, it's simply a mirror of prometheus/master (so I can still contribute other patches). Send out another PR, to the xrate branch, and I'll be happy to merge it.