Prom Metric - gauge is missing, what's it's equivalent?

[RichardWright]

Hi!

Coming from prom-client, what's the equivalent to a gauge when recording metrics? I tried value recorder but it's really not the same. Is Value observer very different to Value recorder?

Any advice would be appreciated.

Thanks

[dyladan]

I think value recorder is most likely what you're looking for. When you say it behaves differently, what do you mean?

The value recorder and value observer use the same aggregation but the observer calls a callback periodically which checks a value and the value recorder is called by the user whenever is appropriate.

[RichardWright]

I've just looked at some value observer code and the output appears to be a gauge not a histrogram. Wouldn't that mean they use a different aggregation?

[dyladan]

I thought they both output gauge. I'll look into it

[weyert]

I am having the same question. The serialised code [1] suggest it will only return a gauge type when its:

• aggregator kind is last value (not sure how to get this aggregator kind)
• aggregator kind is sum but the metric kinds are not COUNTER and SUM_OBSERVER

[1]

opentelemetry-js/packages/opentelemetry-exporter-prometheus/src/PrometheusSerializer.ts

Line 92 in bf99144

/** MetricKind.UP_DOWN_COUNTER and MetricKind.UP_DOWN_SUM_OBSERVER */