Log SSL Connection Information

[samin36]

Before opening a feature request against this repo, consider whether the feature should/could be implemented in the other OpenTelemetry client libraries. If so, please open an issue on opentelemetry-specification first.

Request
I have successfully set up the HTTP metric/trace exporter to use SSL/TLS, but I am not seeing any connection specific information logged anywhere. With debug log level, I see the [OTLP HTTP Client] Session state: connected message, but that does not contain sufficient information.

Describe the solution you'd like
Upon establishing an HTTPS connection, the negotiated TLS version and the Cipher suite should be logged. Logging the entire handshake would also be nice to have for debugging purposes.

[lalitb]

libcurl verbose mode is switched off by default:

opentelemetry-cpp/ext/src/http/client/curl/http_operation_curl.cc

Line 591 in 8f97cab

rc = SetCurlLongOption(CURLOPT_VERBOSE, 0L);

We can make it configurable. Though need to validate if this will also dump SSL handshake data.
Contributions are welcome in general to add this support.

[github-actions]

This issue is available for anyone to work on. Make sure to reference this issue in your pull request.
✨ Thank you for your contribution! ✨

[samin36]

libcurl verbose mode is switched off by default:

opentelemetry-cpp/ext/src/http/client/curl/http_operation_curl.cc

Line 591 in 8f97cab

rc = SetCurlLongOption(CURLOPT_VERBOSE, 0L);

We can make it configurable. Though need to validate if this will also dump SSL handshake data. Contributions are welcome in general to add this support.

Agree with making it configurable. We should be able to use the CURLOPT_DEBUGFUNCTION option to specify a callback that logs all the necessary information.

[samin36]

I can take a shot at implementing this. Sign me up!

[lalitb]

Thanks @samin36, it's your's now.

[github-actions]

This issue was marked as stale due to lack of activity.