ExcludeClassPropagator extension for OpenTelemetry Java Agent

Purpose

Wraps the default W3CTraceContextPropagator to conditionally exclude ClassNames from having context injected into outgoing requests/messages in Java Apps that instrumented by OpenTelemetry Java Agent.

This can be used to ensure that outgoing requests/messages do not contain context propagation "extra data" like traceparent in their headers, while still allowing the instrumented Apps to emit traces.

Requirements

• Gradle 8.14.2
• Java 8

Building manually

1. Clone the repo into your <project-root-directory>

   git clone https://github.com/zephyrdark/exclude-class-propagator.git
   

2. Change directory into the repo

   cd exclude-class-propagator
   

3. Ensure formatting

   gradle spotlessApply
   

4. Running below command will build 3 .jar files into build/libs

   gradle build
   

   Either of these built .jar files can be used:
   • opentelemetry-javaagent-with-excludeClassPropagator.jar
   • exclude-class-propagator-1.0-all.jar

Usage

1. You can choose to either use the extended Otel Java Agent opentelemetry-javaagent-with-excludeClassPropagator.jar as follows:

   java -javaagent:path/to/opentelemetry-javaagent-with-excludeClassPropagator.jar \
   -Dotel.propagators.tracecontext-exclude \
   -Dotel.instrumentation.propagators.tracecontext-exclude.injection=package1.ClassName1,package2.ClassName2 \
   -jar path/to/target-app.jar
   

   or the original Otel Java Agent opentelemetry-javaagent.jar with the extension jar:

   java -javaagent:path/to/opentelemetry-javaagent.jar \
   -Dotel.javaagent.extensions=build/libs/exclude-class-propagator.jar \
   -Dotel.propagators.tracecontext-exclude \
   -Dotel.instrumentation.propagators.tracecontext-exclude.injection=package1.ClassName1,package2.ClassName2 \
   -jar path/to/target-app.jar
   

Reference

• https://github.com/open-telemetry/opentelemetry-java-instrumentation/tree/main/examples/extension