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Trace id can't be decoded by agent due to being transmitted as float

See original GitHub issue

My team is currently experimenting with tracing a system that in part consists of Python and Java applications. On the Python side of things we use dd-trace-py. All outgoing requests include the following headers for distributed tracing: { 'x-datadog-trace-id': str(tracer.current_span().trace_id), 'x-datadog-parent-id': str(tracer.current_span().span_id) } These ids are as far as I understand 64-bit unsigned integers.

When a Java application receive a request with such headers and try to submit them to the trace agent, the id will be incorrectly (imo) encoded by msgpack as float64 rather than uint64. The trace agent expect the trace id to be an int so it throws the following error and drops the traces: ERROR (receiver.go:386) - cannot decode v0.4 traces payload: msgp: attempted to decode type "float64" with method for "int"

I have created a ticket in the msgpack-java repository which can be found here. I’m posting this here because there may be others that have this problem, and I thought I’d let you know.

Currently we’ve worked around this by swapping out the objectMapper in DDApi, with the unfortunate use of reflection, to a subclass that use a MessagePackGenerator that contains the fix suggested in the pull request related to the issue ticket linked above.