[chore] Support connector in metrics.go.tmpl NewMetricsBuilder

[Dainerx]

Description

I discovered this issue while trying to upgrade the opentelemetry collector from v0.111.0 to v0.119.0 that was released two weeks ago. To reproduce please take a look at the issue below.

Link to tracking issue

Fixes #12402

Testing

Run make generate on a processor or connector component

[codecov]

Codecov Report

Attention: Patch coverage is 90.62500% with 45 lines in your changes missing coverage. Please review.

Project coverage is 92.06%. Comparing base (dc4fab3) to head (062c7ef).
Report is 6 commits behind head on main.

Files with missing lines	Patch %	Lines
...leconnector/internal/metadata/generated_metrics.go	91.83%	27 Missing and 2 partials ⚠️
...pleconnector/internal/metadata/generated_config.go	82.85%	8 Missing and 4 partials ⚠️
...econnector/internal/metadata/generated_resource.go	91.11%	4 Missing ⚠️

❌ Your patch status has failed because the patch coverage (90.62%) is below the target coverage (95.00%). You can increase the patch coverage or adjust the target coverage.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #12403      +/-   ##
==========================================
- Coverage   92.09%   92.06%   -0.03%     
==========================================
  Files         473      477       +4     
  Lines       25590    26070     +480     
==========================================
+ Hits        23567    24002     +435     
- Misses       1612     1651      +39     
- Partials      411      417       +6     

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[bogdandrutu]

@Dainerx what other component do you have that emits metrics?

[Dainerx]

@bogdandrutu in my use case, processors and connectors do emit metrics.

My main concern is the if statement surrounding only the function signature. Also, I expected adding a new class in the metadata schema.

[bogdandrutu]

My main concern is the if statement surrounding only the function signature. Also, I expected adding a new class in the metadata schema.

That should be fixed.

processors and connectors do emit metrics.

How come? I can see why connectors may do it, but how come the processors?

[Dainerx]

How come? I can see why connectors may do it, but how come the processors?

Processors can have mutate data capabilities, the metrics generation processor does generate metrics. Although, this is possible, I agree with you it's not a best practice to use a processor to generate metrics.

I am fine with only supporting connector scrapper, and receiver. We should also:

1. Add a sample connector to be used for testing purposes to check the output of mdatagen against it
2. Update the README file.

WDYT?

[bogdandrutu]

I am ok with this proposal.

[bogdandrutu]

I am not sure what changed, but this looks very strange that every line is updated.

[dmitryax]

Why is this added to a connector? The metrics section is supposed to be set on scraping receivers only

[dmitryax]

Sorry, I missed the discussion above... Do you have a connector emitting metrics open sourced? It's not in contrib, right?

[Dainerx]

Sorry, I missed the discussion above... Do you have a connector emitting metrics open sourced? It's not in contrib, right?

Right

[Dainerx]

Revert changes here

[linux-foundation-easycla]

The committers listed above are authorized under a signed CLA.

• ✅ login: Dainerx / name: Oussama Ben Ghorbel (062c7ef)

No longer blocking this.

[Dainerx]

Pinging for review @dmitryax @sincejune @bogdandrutu