Prometheus.erl support.

[deadtrickster]

Hello!

I want to add prometheus.erl support.

Metrics:

• counter - non-negative number. Always can only go up (or reset);
• gauge - number. Can be incremented/decremented or set to arbitrary value;
• summary - right now just samples count and sum;
• histogram - samples count/sum + per bucket count.

How this could be mapped to erlang-metrics metrics?

Thank you

[deadtrickster]

ping

[benoitc]

@deadtrickster go ahead, pr will be welcome :)

[benoitc]

@deadtrickster sorry was short on my answer :)

IMO you can do like what i did in grapherl:

https://github.com/benoitc/erlang-metrics/blob/master/src/metrics_grapherl.erl#L32-L34

doing what you do on counter , gauge and histogram is ok. then it's about the application to handle the logic. Tjoughts?

[deadtrickster]

Now when you use prometheus, what you think is be best way to approach it? What I want personally is something enough to get hackney metrics.

[benoitc]

What I want personally is something enough to get hackney metrics.

@deadtrickster how do you mean? Having metrics calculated initially ?

[tsloughter]

@deadtrickster any movement on this? I can take a look.

[deadtrickster]

@tsloughter Hi,
I just don't know for which version prometheus adatapter should be written. Hackney uses 1.x, current is 2.x. ¯_(ツ)_/¯

[benoitc]

@deadtrickster why do you care about the version used by hackney? Erlang-metrics is using a feature not available in Erlang < 17 , so until the support of Erlang 16 is removed this could likely happen unfortunately.

[deadtrickster]

because I have some hackney code I want to get metrics from:-). Do you have an estimation for hackney 2? I assume this will use metric2?

[benoitc]

@deadtrickster are you still up to provide a PR for it? Would be interrested to included it in next release.

[deadtrickster]

yes, for version 2?

[benoitc]

we can bump the next erlang-metrics and make it compatible for current hackney version as well :)

[entone]

@deadtrickster I was actually going to ping you about this, but now i see you've already opened an issue. Any update on this?