Invalid `x-datadog-sampling-priority` header format

[Omar-Bishtawi]

Problem Description

in the context propagation format mentioned in Datadog documentation it's mentioned that x-datadog-sampling-priority is used to specify the sampling decision made for the represented span as an integer, in decimal format.

currently, dd-trace-cpp throws this error when it receives x-datadog-sampling-priority of 0.0

[2024-08-21 11:30:57.214][40][error][tracing] [source/extensions/tracers/datadog/tracer.cc:133] Unable to extract span context. Creating a new trace instead. Error [error 16]: While extracting trace context in the Datadog propagation style from the following headers: [x-datadog-trace-id: 1440130837183445134, x-datadog-parent-id: 10794189177351031766, x-datadog-sampling-priority: 0.0], an error occurred: Could not extract Datadog-style sampling priority from x-datadog-sampling-priority: 0.0 Integer has trailing characters in: "0.0"

Is this a correct behavior or not ?
I think 0.0 or 1.0 or any decimal value should be accepted as valid input. if not, the documentation page needs to be updated

Reproduction steps

1. use dd-trace-py to generate a DD context.

 tracer.context_provider.activate(
            Context(
                trace_id=int(datadog_json.get('x-datadog-trace-id')),
                span_id=int(datadog_json.get('x-datadog-parent-id')),
                sampling_priority=float(datadog_json.get('x-datadog-sampling-priority', 1))
            )
        )

notice that in dd-trace-py they accept both int/float types for sampling-priority header

2. make a request to C++ application that is instrumented using dd-trace-cpp , in our case the request is made to the envoy proxy that has datadog tracing enabled on it.

[dgoffredo]

Decimal as opposed to hexadecimal. It parses an integer and so will reject text that contains a decimal point. Sorry for the use of the ambiguous term "decimal."

[Omar-Bishtawi]

thanks for the clarification @dgoffredo , I think this issue isn't related to dd-trace-cpp.
but an enhancement can be made from dd-trace-py to not send/accept float values in dd-context if float isn't an acceptable input.