Should MetricProducer be in the spec?

[anuraaga]

I was trying to match up the current metrics SDK implementation vs the spec and one interface I was surprised not to find there is MetricProducer.

https://github.com/open-telemetry/opentelemetry-java/blob/main/sdk/metrics/src/main/java/io/opentelemetry/sdk/metrics/export/MetricProducer.java#L20
https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/metrics/sdk.md#metricexporter

Is this something we would expect to be there? /cc @jsuereth

[anuraaga]

/cc @jmacd @reyang Also in case you happen to have any ideas on a metric producer

[reyang]

My guess - MetricProducer is a Java specific thing, which could be useful for bridging other systems such as Micrometer.

At least for now I don't see that the SDK spec will take it.

[anuraaga]

@reyang Micrometer shim doesn't use MetricProducer, it uses the API directly. OpenCensus shim does use it, but in that case I would expect it to be in the spec. I'm not aware of anything java-specific about this type - if it's just an ordering issue, that opencensus hasn't been spec'd yet, I can see if there's a way to move that into an internal type.

[reyang]

@anuraaga what you said makes sense to me 👍

[reyang]

FYI - there was something similar in OpenTelemetry .NET open-telemetry/opentelemetry-dotnet#2683.