How to send a HTTP request header in OTEL signals emitted from instrumented application

[shadow0wolf]

Send a HTTP request header in OTEL signals emitted from instrumented application , this header has dynamic value which is set by application and changes frequently during application lifecycle (unlike the one set with value "otel.exporter.otlp.headers) .
I went through manual instrumentation docs but couldnt find anything.

[trask]

hi @shadow0wolf! check out open-telemetry/opentelemetry-java#4630, does that (internal for now) API address what you need?

[shadow0wolf]

exactly my use case , i intent to set a header which can change value during application lifetime , this value is supposed to be sent to a OTEL collector (implementing a custom authenticator for validation) , unfortunately this feature seems not to be available for GRPC exporters and it is still internal.

[trask]

it may be useful to open an issue in https://github.com/open-telemetry/opentelemetry-java about the stability plan for this feature

is there a reason you need to use the gRPC exporter? (we are curious about this in general, as we have started guiding people towards the HTTP exporter more)

[shadow0wolf]

no specific reason for grpc apart from it being available as an option in case required , the problem with this specifically is open-telemetry/opentelemetry-java#4630 , the supplier function which adds dynamic headers in telemetry requests is only invoked after a 401 response or during the Sender class initialization , i require it be invoked for each request , (the supplier function is required to be in send method of sender and not just on it's constructor) , @trask

[trask]

is this the same as open-telemetry/opentelemetry-java#5959?

[shadow0wolf]

@trask , yes