Zipkin exporter receiving 400 from Open Telemetry Collector

[lukegil]

Description of the bug

When sending a trace to an otel-collector, the client receives a 400:

json: cannot unmarshal string into Go struct field Endpoint.remoteEndpoint.Port of type uint16

A repro of this issue can be found here: https://github.com/lukegil/repro-ot-issue

This occurs when a basic "get" is traced, as well as in-the-field cases like when automatically tracing calls to Amazon Cognito.

It appears that the zipkin exporter is explicitly setting port as a string (here, though I could be wrong). Zipkin defines remoteEndpoint.port as being an int.

Share details about your runtime

Operating system details: MacOS 14.1.2 (but also seen on Amz linux) RUBY_ENGINE: "ruby" RUBY_VERSION: "3.0.6" RUBY_DESCRIPTION: "ruby 3.0.6p216 (2023-03-30 revision 23a532679b) [x86_64-darwin22]"

Share a simplified reproduction if possible https://github.com/lukegil/repro-ot-issue

Thanks for all your work! Let me know if I can help