Add user agent for OTLP http/grpc client

[owent]

Signed-off-by: owent admin@owent.net

Fixes #1656

Changes

Add user agent for OTLP http/grpc client

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

• CHANGELOG.md updated for non-trivial changes
• Unit tests have been added
• Changes in public API reviewed

[esigo]

LGTM
Thanks for the fix :)

[codeboten]

Thanks for the quick turn around on the fix! Will there be a separate PR to add the user agent to the grpc exporter or does this address both http and grpc OTLP exporters?

[marcalff]

LGTM

[lalitb]

Thanks for the quick turn around on the fix! Will there be a separate PR to add the user agent to the grpc exporter or does this address both http and grpc OTLP exporters?

This is for http OTLP exporter. Separate PR would be done for gRPC.

[lalitb]

LGTM. Thanks for adding this.

[codecov]

Codecov Report

Merging #1657 (961f204) into main (1dc810d) will increase coverage by 0.02%.
The diff coverage is n/a.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1657      +/-   ##
==========================================
+ Coverage   84.39%   84.41%   +0.02%     
==========================================
  Files         170      170              
  Lines        5130     5130              
==========================================
+ Hits         4329     4330       +1     
+ Misses        801      800       -1     

Impacted Files	Coverage Δ
sdk/src/trace/batch_span_processor.cc	91.41% <0.00%> (+0.79%)	⬆️

[lalitb]

Thanks for the quick turn around on the fix! Will there be a separate PR to add the user agent to the grpc exporter or does this address both http and grpc OTLP exporters?

This is for http OTLP exporter. Separate PR would be done for gRPC.

BTW, I hope gRPC-cpp allows overriding default user-agent using ClientContext::AddMetaData(). If not, it would be difficult to add support, as the other approach using Interceptors at client side is still experimental ( https://grpc.github.io/grpc/cpp/classgrpc_1_1experimental_1_1_interceptor.html).

[owent]

Thanks for the quick turn around on the fix! Will there be a separate PR to add the user agent to the grpc exporter or does this address both http and grpc OTLP exporters?

This is for http OTLP exporter. Separate PR would be done for gRPC.

BTW, I hope gRPC-cpp allows overriding default user-agent using ClientContext::AddMetaData(). If not, it would be difficult to add support, as the other approach using Interceptors at client side is still experimental ( https://grpc.github.io/grpc/cpp/classgrpc_1_1experimental_1_1_interceptor.html).

gRPC user agent is added now. We could use grpc::ChannelArguments::SetUserAgentPrefix to prepend otel user agent before the default value(which is "grpc-c++/GRPC VERSION").

[owent]

Thanks for the quick turn around on the fix! Will there be a separate PR to add the user agent to the grpc exporter or does this address both http and grpc OTLP exporters?

Should we use OTel-OTLP-Exporter-Cpp/1.2.3 instead of OTel OTLP Exporter Cpp/1.2.3 ?
According to https://datatracker.ietf.org/doc/html/rfc7231#section-5.5.3 user agent use token, which is defined at https://datatracker.ietf.org/doc/html/rfc7230#section-3.2.6 and do not contains spaces.

[lalitb]

Should we use OTel-OTLP-Exporter-Cpp/1.2.3 instead of OTel OTLP Exporter Cpp/1.2.3 ?

Good point. I think we should rename, as produce-token can't contain spaces.

[lalitb]

Should we use OTel-OTLP-Exporter-Cpp/1.2.3 instead of OTel OTLP Exporter Cpp/1.2.3 ?

Good point. I think we should rename, as produce-token can't contain spaces.

@codeboten - What do you think of the format without spaces, to be in-compliant with the rfc?

[lalitb]

As discussed in the SIG meeting, we will stick to the user-agent format as given in the specs , and change it later if required. Merging the PR based on this.