Update: Might be obsolete based on Datadog + OpenTracing: Embracing the open standard for APM from December 6, 2017
It’s hard to find the docs, but look in the official Python source and find them:
parent_trace_id = request.headers.get(‘x-ddtrace-parent_trace_id‘) parent_span_id = request.headers.get(‘x-ddtrace-parent_span_id‘)
Also, the unofficial Java documents them:
The TraceServletFilter traces every incoming request. If the client request includes the x-ddtrace-parent_trace_id and x-ddtrace-parent_span_id headers, that indicated span is used as the parent trace and span. Otherwise, a new trace is created. Once the request is complete, the new span or trace is closed and sent to Datadog APM.