Metrics examplars

[dyladan]

Spec: https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/metrics/sdk.md#exemplar

A metrics exemplar is a trace that is representative of the metrics being collected. The spec requires that exemplars be implemented in a way such that they may be disabled and that if disabled they should have no performance impact (collection should be disabled, not just export). When enabled, the exemplars will come from the currently active context.

Properties:

• Value

• Time

• Attributes

• Trace ID

• Span ID

• ExemplarFilter determines if a meausrement should be sampled

  • value of measurement
  • attributes of measurement
  • context of measurement
  • timestamp

• ExemplarReservoir provides a method to offer measurements to the reservoir and to collect accumulated exemplars

  • Methods
    • offer
      • value of measurement
      • attributes of measurement
      • context of measurement
      • timestamp
    • collect
      • returns accumulated exemplars

Built-in reservoirs

• SimpleFixedSizeExemplarReservoir
• AlignedHistogramBucketExemplarReservoir

[srikanthccv]

Happy to take this up if no one has already started working on it

[dyladan]

go ahead. You may want to keep an eye on #2625 since it changes what we have quite a bit

[legendecas]

@lonewolf3739 a friendly question: are you planning to work on the integration of metric exemplars and the View API?

[srikanthccv]

@legendecas yes, that's why I didn't use fixes in the PR description that would close this issue. And there is also tiny env related work to do. I will work on the wiring up the stuff as well when other components are ready.

[github-actions[bot]]

This issue is stale because it has been open 60 days with no activity. Remove stale label or comment or this will be closed in 14 days.

[github-actions[bot]]

This issue is stale because it has been open 60 days with no activity. Remove stale label or comment or this will be closed in 14 days.

[pichlermarc]

Hi @srikanthccv :slightly_smiling_face:

Friendly question: are you still planning to work on this? :thinking: Otherwise I'll mark this as up-for-grabs in case someone else has some cycles to work on it. :slightly_smiling_face:

[srikanthccv]

@pichlermarc I won't be able to allocate time for this - unassigning myself. Thanks.

[vothanhbinhlt]

Hello team, any update on this? I am waiting for this feature, I am would like to setup a Nodejs application work with Exemplars, Prometheus and Tempo

[pichlermarc]

AFAIK no one is currently working on this. Interest in it might pick up once the specification is marked stable.

[antogyn]

Hey, is there any way to sponsor this? We'd like to switch to the sdk for metrics but this is a blocker.

[pichlermarc]

@antogyn this issue is looking for someone to implement it.

It's a feature that's in the OTel spec, so it does not need to go through any special approval process. We will accept code-contributions if someone decides to implement it, unless it's submitted within a feature-freeze period (the first of which is coming up mid December).

[pichlermarc]

Hi all, I will close this feature-request as ACCEPTED since the specification is now stable.

This means that it has been refined into a concrete work-item (#5147). Implementation progress will be tracked on #5147 from here on out. I marked it as type:feature rather than feature-reuqest to ensure that it's clear that this is a feature that is accepted and can be worked on.