[otel-tracing] Initial opentelemetry support

[lengrongfu]

issues: #3451

Local Repose workflows result :

[codecov-commenter]

Codecov Report

Merging #3481 (5d1ed40) into main (38ab4c6) will decrease coverage by 0.60%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##             main    #3481      +/-   ##
==========================================
- Coverage   56.38%   55.78%   -0.61%     
==========================================
  Files         102      103       +1     
  Lines        7324     7543     +219     
==========================================
+ Hits         4130     4208      +78     
- Misses       2541     2675     +134     
- Partials      653      660       +7     

Impacted Files	Coverage Δ
...bution/distribution/configuration/configuration.go	56.30% <0.00%> (-5.74%)	⬇️
...stribution/registry/storage/cache/memory/memory.go	87.17% <0.00%> (-2.53%)	⬇️
...distribution/distribution/registry/handlers/app.go	45.04% <0.00%> (-1.13%)	⬇️
...distribution/registry/storage/cache/redis/redis.go	0.00% <0.00%> (ø)
...hub.com/distribution/distribution/health/health.go	45.26% <0.00%> (ø)
.../distribution/distribution/notifications/bridge.go	53.52% <0.00%> (+0.39%)	⬆️

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[lengrongfu]

@milosgajdos Hi，What else do I need to do about this PR。

[aaronlehmann]

It would also be great to support client-side tracing in the registry client. In a recent project, I had to fork much of the client code to use http.NewRequestWithContext instead of http.NewRequest.

[lengrongfu]

It would also be great to support client-side tracing in the registry client. In a recent project, I had to fork much of the client code to use http.NewRequestWithContext instead of http.NewRequest.

Yes, your idea is great, but I don't know whether the registry client is the part of the distribution code or the project. If you can write in more detail, I can add this part of the function together. @aaronlehmann

[aaronlehmann]

Yes, your idea is great, but I don't know whether the registry client is the part of the distribution code or the project

It is in the registry/client directory in this repository.

[aaronlehmann]

Doesn't this need to be changed to NewRequestWithContext? There are also some uses of NewRequest elsewhere in this file and in registry/client/auth/session.go and registry/client/blob_writer.go.

[lengrongfu]

What is the reason for changing to NewRequestWithContext here? If we are to achieve trace injection, I think it can be achieved by otel.GetTextMapPropagator().Inject(traceCtx,propagation.HeaderCarrier(req.Header)).

[aaronlehmann]

I had thought that the transport would get the span information from the context, but if that's not how it works you can disregard the comment.

[lengrongfu]

You didn't understand it wrong,
1、Obtain the trace from the context and create a span, if there is one, create a new span if not

span, traceCtx := tracing.StartSpan(ctx, "blobs.delete")

2、Inject trace into other http services, go through the following steps

otel.GetTextMapPropagator().Inject(traceCtx, propagation.HeaderCarrier(req.Header))

[milosgajdos]

This will need a rebase

[milosgajdos]

Can you please rebase @lengrongfu

[milosgajdos]

hey @lengrongfu do you mind rebasing please?

[lengrongfu]

@milosgajdos hi， I don't understand how to do rebase, can you tell me the steps? thanks.