x-cloud-trace-context pattern was changed by google when setup gRPC http2.0 on Cloud RUN

[paralelocslucasmagalhaes]

Hi guys.. I tested the Cloud Trace Propagator on Cloud Run running a gRPC service with HTTP 2.0 enabled and figure out a problem.

On my tests I notice the pattern of x-cloud-trace-context the Google's Services send was different than "trace_id/span_id;o=Flag". On my test I've received just "trace_id/span_id" without the ";o=Flag".

So.. the actual code implemented at Cloud Trace Propagator Class does "match = re.fullmatch(_TRACE_CONTEXT_HEADER_RE, header)" The re expression wasn't fullfiled and return None.

I have a suspicion that the change could be part of HTTP2.0 setup, cause others "REST Service" running on HTTP1.0 the x-cloud-trace-context pattern is the way we expected.

Originally posted by @paralelocslucasmagalhaes in #109 (comment)

[aabmass]

On my tests I notice the pattern of x-cloud-trace-context the Google's Services send

Which google services do you mean here? A Google service is calling your gRPC service?

On my tests I notice the pattern of x-cloud-trace-context the Google's Services send was different than "trace_id/span_id;o=Flag". On my test I've received just "trace_id/span_id" without the ";o=Flag".

Regardless of the cause, I think you're right that the ;o=Flag part should be optional–that's what we have in the JS propagator at least: https://github.com/GoogleCloudPlatform/opentelemetry-operations-js/blob/ddbfee05c77e36b24fdf308325429128b801b216/packages/opentelemetry-cloud-trace-propagator/src/CloudPropagator.ts#L74

[aabmass]

Golang as well https://github.com/GoogleCloudPlatform/opentelemetry-operations-go/blob/5146b844c1e7cef1b8e17c69c1c0de429cf0ac19/propagator/propagator.go#L36

[punya]

@paralelocslucasmagalhaes, is this problem still relevant to you?

[kamalmarhubi]

It seems clear that there should be agreement across Google's libraries. I think the single character code change + related tests is the correct thing to do here?

[kamalmarhubi]

@punya @aabmass could you review and merge #181 then make a release? The propagator is basically broken without that change. This lost a team member at least several hours investigating why transforming load balancer logs into otel spans wasn't working. Thanks!