Implement MDC auto-instrumentation for log4j2

open-telemetry · Sep 16, 2020 · 65d866f · 65d866f
1 parent 452d5bc
commit 65d866f
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Showing 4 changed files with 12 additions and 6 deletions.
diff --git a/...in/java/io/opentelemetry/instrumentation/auto/log4j/v2_13_2/Log4j2MdcInstrumentation.java b/...in/java/io/opentelemetry/instrumentation/auto/log4j/v2_13_2/Log4j2MdcInstrumentation.java
@@ -40,6 +40,8 @@ public ElementMatcher<ClassLoader> classLoaderMatcher() {
 
   @Override
   public ElementMatcher<? super TypeDescription> typeMatcher() {
+    // need to instrument a class, not an interface (ContextDataProvider) - otherwise helper classes
+    // and resources are not injected
     return named("org.apache.logging.log4j.core.impl.ThreadContextDataInjector");
   }
 

diff --git a/instrumentation/log4j/log4j-2.13.2/library/README.md b/instrumentation/log4j/log4j-2.13.2/library/README.md
@@ -31,7 +31,7 @@ a log statement is made when a span is active.
 
 - `traceId`
 - `spanId`
-- `traceFlags`
+- `sampled`
 
 You can use these keys when defining an appender in your `log4j.xml` configuration, for example
 

diff --git a/...main/java/io/opentelemetry/instrumentation/auto/log4j/v2_7/Log4j27MdcInstrumentation.java b/...main/java/io/opentelemetry/instrumentation/auto/log4j/v2_7/Log4j27MdcInstrumentation.java
@@ -50,7 +50,8 @@ public String[] helperClassNames() {
 
   @Override
   public ElementMatcher<ClassLoader> classLoaderMatcher() {
-    return not(hasClassesNamed("org.apache.logging.log4j.core.util.ContextDataProvider"));
+    return hasClassesNamed("org.apache.logging.log4j.core.impl.ContextDataInjectorFactory")
+        .and(not(hasClassesNamed("org.apache.logging.log4j.core.util.ContextDataProvider")));
   }
 
   @Override

diff --git a/...ava/io/opentelemetry/instrumentation/auto/logback/v1_0_0/LoggingEventInstrumentation.java b/...ava/io/opentelemetry/instrumentation/auto/logback/v1_0_0/LoggingEventInstrumentation.java
@@ -16,6 +16,9 @@
 
 package io.opentelemetry.instrumentation.auto.logback.v1_0_0;
 
+import static io.opentelemetry.instrumentation.api.log.LoggingContextConstants.SAMPLED;
+import static io.opentelemetry.instrumentation.api.log.LoggingContextConstants.SPAN_ID;
+import static io.opentelemetry.instrumentation.api.log.LoggingContextConstants.TRACE_ID;
 import static io.opentelemetry.javaagent.tooling.bytebuddy.matcher.AgentElementMatchers.implementsInterface;
 import static java.util.Collections.singletonMap;
 import static net.bytebuddy.matcher.ElementMatchers.isMethod;
@@ -78,7 +81,7 @@ public static class GetMdcAdvice {
     public static void onExit(
         @Advice.This ILoggingEvent event,
         @Advice.Return(typing = Typing.DYNAMIC, readOnly = false) Map<String, String> contextData) {
-      if (contextData != null && contextData.containsKey("traceId")) {
+      if (contextData != null && contextData.containsKey(TRACE_ID)) {
         // Assume already instrumented event if traceId is present.
         return;
       }
@@ -90,10 +93,10 @@ public static void onExit(
 
       Map<String, String> spanContextData = new HashMap<>();
       SpanContext spanContext = currentSpan.getContext();
-      spanContextData.put("traceId", spanContext.getTraceIdAsHexString());
-      spanContextData.put("spanId", spanContext.getSpanIdAsHexString());
+      spanContextData.put(TRACE_ID, spanContext.getTraceIdAsHexString());
+      spanContextData.put(SPAN_ID, spanContext.getSpanIdAsHexString());
       if (spanContext.isSampled()) {
-        spanContextData.put("sampled", "true");
+        spanContextData.put(SAMPLED, "true");
       }
 
       if (contextData == null) {