Propagating Java Trace Context
The Datadog APM Tracer supports B3 and W3C Trace Context header extraction and injection for distributed tracing.
You can configure injection and extraction styles for distributed headers.
The Java Tracer supports the following styles:
- Datadog:
datadog - B3 Multi Header:
b3multi (b3 alias is deprecated) - W3C Trace Context:
tracecontext (Available since 1.11.0) - B3 Single Header:
b3 single header (b3single)
Injection styles can be configured using:
- System Property:
-Ddd.trace.propagation.style.inject=datadog,b3multi - Environment Variable:
DD_TRACE_PROPAGATION_STYLE_INJECT=datadog,b3multi
The value of the property or environment variable is a comma (or space) separated list of header styles that are enabled for injection. The default setting is datadog,tracecontext injection styles.
Extraction styles can be configured using:
- System Property:
-Ddd.trace.propagation.style.extract=datadog,b3multi - Environment Variable:
DD_TRACE_PROPAGATION_STYLE_EXTRACT=datadog,b3multi
The value of the property or environment variable is a comma (or space) separated list of header styles that are enabled for extraction. By default, the datadog and tracecontext extraction styles are enabled using the datadog,tracecontext setting, meaning the datadog style has higher priority than the tracecontext style.
When multiple extraction styles are enabled, the extraction attempt is done on the order those styles are configured, using the first successful extracted value. If later valid trace contexts are found, they are terminated and appended as span links. Moreover, if the tracecontext style is enabled, W3C Tracestate is propagated if W3C Traceparent matches the extracted context.
For reference details about the context propagation settings and other configuration, read Java Tracing Library Configuration.
Further Reading
Additional helpful documentation, links, and articles:
