Separate OpenTelemetry.Api B3 Trace Propagator to a new Nuget Package

[dmpe]

part of #1881

Changes

As described in #1881, this MR creates a new Nuget Package (and VS project inside of solution) for B3 tracing propagation. As suggested by @cijothomas, and furher documented here https://opentelemetry.io/docs/reference/specification/context/api-propagators/#propagators-distribution, B3 as well as Jaeger propagators need to be independent, extension packages.

Please, can you approve workflows so that tests etc could be executed. Thanks.

Details

• 2 new projects for both the main the nuget package as well as the testing project
• public api (net2.0+net462) remained the same, as I did not adjust the code logic of b3 tracing itself

For significant contributions please make sure you have completed the following items:

• Design discussion issue Support for Jaeger Propagator #1881

[reyang]

Looks like a breaking change.
I would suggestion the following path:

1. Do not remove existing B3 APIs, consider adding https://docs.microsoft.com/en-us/dotnet/api/system.obsoleteattribute to these B3 APIs.
2. Create an issue to track the removal of the B3 APIs in the next MAJOR release (e.g. 2.x).

[dmpe]

Looks like a breaking change. I would suggestion the following path:

1. Do not remove existing B3 APIs, consider adding https://docs.microsoft.com/en-us/dotnet/api/system.obsoleteattribute to these B3 APIs.
2. Create an issue to track the removal of the B3 APIs in the next MAJOR release (e.g. 2.x).

Done. It has been marked as obsolete (just functions, not attributes, was not sure about that) and a new issue #3259 has been created as well.

Also, package has been renamed as suggested (thanks @alanwest). Tests were executed locally, and run fine.

Breaking changes are avoided

[reyang]

LGTM.

[dmpe]

thanks @reyang - I will bring this in the next 2 days to the finish...

[cijothomas]

@dmpe I;d suggest to break this down into smaller scoped PRs.

1. Start adding a new project and add B3 propagator (its diff. namespace from existing, but rest of code is exact same as existing one)
2. Add Readme.md files and tests
3. Modify all existing code in this repo to switch to new propagator.
4. Obsolete the current B3Propagator.

[cijothomas]

Please, can you approve workflows so that tests etc could be executed. Thanks.

Please, can you approve workflows so that tests etc could be executed. Thanks.

^ _ once you make a smaller PR and get it merged, Github will automatically trigger CI checks for your PR. (the restriction is only for 1st time contributions. So you have a good reason to make Github think you are not 1st time contributor!)

[dmpe]

@dmpe I;d suggest to break this down into smaller scoped PRs.

1. Start adding a new project and add B3 propagator (its diff. namespace from existing, but rest of code is exact same as existing one)
2. Add Readme.md files and tests
3. Modify all existing code in this repo to switch to new propagator.
4. Obsolete the current B3Propagator.

Thanks.
I have added both test and main project, so this shall be ready for review.

[codecov]

Codecov Report

Merging #3244 (8b6c7c8) into main (72fcbf3) will decrease coverage by 0.03%.
The diff coverage is 85.86%.

@@            Coverage Diff             @@
##             main    #3244      +/-   ##
==========================================
- Coverage   85.48%   85.44%   -0.04%     
==========================================
  Files         261      262       +1     
  Lines        9410     9502      +92     
==========================================
+ Hits         8044     8119      +75     
- Misses       1366     1383      +17     

Impacted Files	Coverage Δ
...enTelemetry.Extensions.Propagators/B3Propagator.cs	85.86% <85.86%> (ø)
src/OpenTelemetry/BatchExportProcessor.cs	84.21% <0.00%> (-3.16%)	⬇️
...metryProtocol/Implementation/ActivityExtensions.cs	90.94% <0.00%> (-0.87%)	⬇️
...Telemetry/Internal/SelfDiagnosticsEventListener.cs	97.65% <0.00%> (+0.78%)	⬆️

[cijothomas]

@dmpe Almost ready to merge this PR. Left a few minor comments, you may address it in a follow up, but make sure the CI is green!

[dmpe]

The api compatibility test has failed https://github.com/open-telemetry/opentelemetry-dotnet/runs/6371440160?check_suite_focus=true previously but it is not clear to me as to why? Otherwise, fixed as suggested.

[cijothomas]

The api compatibility test has failed https://github.com/open-telemetry/opentelemetry-dotnet/runs/6371440160?check_suite_focus=true previously but it is not clear to me as to why? Otherwise, fixed as suggested.

Its a flaky test - #2885