[Api] support for adding default tags to tracer

[alimahboubi]

Fixes #6016
Design discussion issue #6016

Changes

This pull request adds a new overload to the TracerProvider.GetTracer method to support the inclusion of tags, similar to the new ActivitySource constructor overload in .NET 9. This allows users to associate initial tags with a Tracer (and therefore the underlying ActivitySource), which can be used to differentiate application instances with different configurations. These tags are applied to all activities created by the ActivitySource.

The new overload is:

public Tracer GetTracer(string name, string? version = null, IEnumerable<KeyValuePair<string, object?>>? tags = null)

[Kielek]

@alimahboubi, it is good practice to execute build locally. In this case it should be done in Release mode. For now, I am not able to compile the code.

Could you please fix it?

[alimahboubi]

@Kielek Thanks for pointing that out! I've fixed the compilation error. I've also run a local build in Release mode to confirm

[alimahboubi]

@Kielek Thanks for the detailed feedback! I've incorporated both of your suggestions:

• The new GetTracer overload is now in the Unshipped file.

• I've updated the GetTracer signature to include the optional version and tags parameters, and adjusted the existing overload accordingly (removing the default parameter).

• I've updated the public contract part.

I've updated the commit with these changes. Please take another look!

[Kielek]

Your assertions are to weak. The goal is to have one instance per tags set. Now, you have multiple instances for the same set of tags.

If you include all changes, tests will be failing. You need to fix the TracerKey.

[Kielek]

Worth to add entry in CHANGELOG under OpenTelemetry.Api

[alimahboubi]

Dear @alanwest and @rajkumar-rangaraj,
This PR has been open for a while, and it has already received approval from one of the approvers. Could you please take a look and, if everything is in order, proceed with the merge?

[xiang17]

Overall looks good.

[codecov]

Codecov Report

Attention: Patch coverage is 90.00000% with 7 lines in your changes missing coverage. Please review.

Project coverage is 86.31%. Comparing base (402ed87) to head (a126785).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
src/OpenTelemetry.Api/Trace/TracerProvider.cs	90.00%	7 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #6137      +/-   ##
==========================================
+ Coverage   86.23%   86.31%   +0.08%     
==========================================
  Files         259      259              
  Lines       11776    11845      +69     
==========================================
+ Hits        10155    10224      +69     
  Misses       1621     1621              

Flag	Coverage Δ
unittests-Project-Experimental	85.92% <90.00%> (-0.21%)	⬇️
unittests-Project-Stable	86.18% <90.00%> (+0.01%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
src/OpenTelemetry.Api/Trace/TracerProvider.cs	91.08% <90.00%> (-2.86%)	⬇️

... and 6 files with indirect coverage changes

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[rajkumar-rangaraj]

@alimahboubi Please resolve the conflicts.

[alimahboubi]

@alimahboubi Please resolve the conflicts.
All set! Conflicts are resolved.