feat(exporter-prometheus): support withoutScopeInfo option

[cjihrig]

Which problem is this PR solving?

This commit adds support for the without_scope_info option (converted to camelCase to match other options) from the spec.

Fixes # N/A

Related: Here are some output snapshots from the Golang library which include the scope labels.

Type of change

• New feature (non-breaking change which adds functionality)

How Has This Been Tested?

• Existing and new tests.

Checklist:

• Followed the style guidelines of this project
• Unit tests have been added

[codecov]

Codecov Report

❌ Patch coverage is 95.45455% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 95.16%. Comparing base (e460f03) to head (fcb2aa0).
⚠️ Report is 2 commits behind head on main.

Files with missing lines	Patch %	Lines
...ry-exporter-prometheus/src/PrometheusSerializer.ts	95.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #5993      +/-   ##
==========================================
- Coverage   95.16%   95.16%   -0.01%     
==========================================
  Files         316      316              
  Lines        9207     9220      +13     
  Branches     2075     2080       +5     
==========================================
+ Hits         8762     8774      +12     
- Misses        445      446       +1     

Files with missing lines	Coverage Δ
...etry-exporter-prometheus/src/PrometheusExporter.ts	96.70% <100.00%> (+0.07%)	⬆️
...ry-exporter-prometheus/src/PrometheusSerializer.ts	95.83% <95.00%> (-0.35%)	⬇️

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[cjihrig]

@pichlermarc would you mind taking a look?

[cjihrig]

The Windows test failure appears to be a flake - #6042

[cjihrig]

Maybe @david-luna could take a look?

[trentm]

@cjihrig Are you able to provide some background for a reviewer that might not be so familiar with Prometheus, or exactly what references you mean by "from the spec.".

I clicked through to open-telemetry/opentelemetry-specification#4223 (comment) but am not sure if that is the best reference here.

[cjihrig]

Sure @trentm. I was looking at this page. Apologies if that shouldn't be referred to as the spec, but I assumed it was based on the "specs" in the URL. From that page, I was referring to:

A Prometheus Exporter MAY support a configuration option to produce metrics without scope labels. The option MAY be named without_scope_info, and MUST be false by default.

I changed the name from snake_case to camelCase to match the other options used in the JS repo.

Looking at the test data from the Golang repo, you can see examples like this one (or most of the other examples in that directory). Note the otel_scope_* labels. Then, look at this example, which disables the scope labels. That example does not contain the otel_scope_* labels.

[pichlermarc]

sorry for the delay on this PR - looks good overall, just one question.

[pichlermarc]

thanks!

[otelbot]

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