Fix race condition on loading SDK
This broke during last merge from DataDog repo because context class
loader is no longer set to the agent's class loader.
MODIFY
agent-tooling/src/main/java/io/opentelemetry/auto/tooling/AgentInstaller.java
agent-tooling/src/main/java/io/opentelemetry/auto/tooling/AgentInstaller.java
@@ -54,11 +54,22 @@ public class AgentInstaller {
public static ResettableClassFileTransformer installBytebuddyAgent(
final Instrumentation inst, final AgentBuilder.Listener... listeners) {
- // need to trigger loading of OpenTelemetry SDK before instrumentation can possibly cause
- // io.opentelemetry.OpenTelemetry to be loaded, since as soon as io.opentelemetry.OpenTelemetry,
- // it looks up implementation via SPI, and if it doesn't find one, it loads the No-op
- // implementation and it cannot be replaced later
+ final ClassLoader savedContextClassLoader = Thread.currentThread().getContextClassLoader();
+ try {
+ // calling (shaded) OpenTelemetry.getTracerFactory() with context class loader set to the
+ // agent class loader, so that SPI finds the agent's (isolated) SDK, and (shaded)
+ // OpenTelemetry registers it, and then when instrumentation calls (shaded)
+ // OpenTelemetry.getTracerFactory() later, they get back the agent's (isolated) SDK
+ //
+ // but if we don't trigger this early registration, then if instrumentation is the first to
+ // call (shaded) OpenTelemetry.getTracerFactory(), then SPI can't see the agent class loader,
+ // and so (shaded) OpenTelemetry registers the no-op TracerFactory, and it cannot be replaced
+ // later
+ Thread.currentThread().setContextClassLoader(AgentInstaller.class.getClassLoader());
OpenTelemetry.getTracerFactory();
+ } finally {
+ Thread.currentThread().setContextClassLoader(savedContextClassLoader);
+ }
INSTRUMENTATION = inst;

Fix race condition on loading SDK (#165)

This broke during last merge from DataDog repo because context class
loader is no longer set to the agent's class loader.