Implement cardinality limits for metrics streams

[bnjjj]

Fixes #1065

Changes

Adding a new function called set_stream_cardinality_limit in opentelemetry_sdk::metrics module to set the stream cardinality limit for metric streams.

Merge requirement checklist

• CONTRIBUTING guidelines followed
• Unit tests added/updated (if applicable)
• Appropriate CHANGELOG.md files updated for non-trivial, user-facing changes
• Changes in public API reviewed (if applicable)

[codecov]

Codecov Report

Attention: Patch coverage is 50.00000% with 2 lines in your changes missing coverage. Please review.

Project coverage is 74.6%. Comparing base (da368d4) to head (0b291fb).
Report is 28 commits behind head on main.

Files	Patch %	Lines
...pentelemetry-sdk/src/metrics/internal/aggregate.rs	50.0%	2 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##            main   #1889     +/-   ##
=======================================
- Coverage   74.6%   74.6%   -0.1%     
=======================================
  Files        122     122             
  Lines      19952   19955      +3     
=======================================
  Hits       14902   14902             
- Misses      5050    5053      +3     

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[BrynCooke]

I think this needs to be implemented as per: https://opentelemetry.io/docs/specs/otel/metrics/sdk/#configuration-1

In particular cardinality can be set on views rather than globally.
Then metric readers.
Then the global limit of 2000.

[cijothomas]

I think this needs to be implemented as per: https://opentelemetry.io/docs/specs/otel/metrics/sdk/#configuration-1

In particular cardinality can be set on views rather than globally. Then metric readers. Then the global limit of 2000.

We are removing Views from initial stable release, so this can only be on a MetricReader or most likely on MeterProvider level only for now.

[lalitb]

@bnjjj - Not sure if I am missing something, but how can this method set_stream_cardinality_limit be used by application to configure the cardinality?

[cijothomas]

it is unclear to this works. See #1889 (comment)

The ideal way is via views, but we should hold off from offering that, given Views are being removed for 1st stable release.

[cijothomas]

Closing inactive PRs. This is definitely something we need for metrics, and hoping to bring it in next 1-2 releases.