Implement MDC auto-instrumentation for log4j2

README.md

@@ -204,6 +204,7 @@ provide the path to a JAR file including an SPI implementation using the system
 | [khttp](https://khttp.readthedocs.io)                                                                                                 | 0.1+                           |
 | [Kubernetes Client](https://github.com/kubernetes-client/java)                                                                        | 7.0+                           |
 | [Lettuce](https://github.com/lettuce-io/lettuce-core)                                                                                 | 4.0+                           |
+| [Log4j 2](https://logging.apache.org/log4j/2.x/)                                                                                      | 2.13.2+                        |
 | [Logback](http://logback.qos.ch/)                                                                                                     | 1.0+                           |
 | [MongoDB Drivers](https://mongodb.github.io/mongo-java-driver/)                                                                       | 3.3+                           |
 | [Netty](https://github.com/netty/netty)                                                                                               | 3.8+                           |

instrumentation/log4j/log4j-2.13.2/auto/log4j-2.13.2-auto.gradle

@@ -0,0 +1,18 @@
+apply from: "$rootDir/gradle/instrumentation.gradle"
+
+muzzle {
+  pass {
+    group = "org.apache.logging.log4j"
+    module = "log4j-core"
+    versions = "[2.13.2,)"
+    assertInverse = true
+  }
+}
+
+dependencies {
+  library group: 'org.apache.logging.log4j', name: 'log4j-core', version: '2.13.2'
+
+  implementation project(':instrumentation:log4j:log4j-2.13.2:library')
+
+  testImplementation project(':instrumentation:log4j:log4j-2.13.2:testing')
+}

instrumentation/log4j/log4j-2.13.2/auto/src/main/java/io/opentelemetry/instrumentation/auto/log4j/v2_13_2/Log4j2Instrumentation.java

@@ -0,0 +1,92 @@
+/*
+ * Copyright The OpenTelemetry Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package io.opentelemetry.instrumentation.auto.log4j.v2_13_2;
+
+import static io.opentelemetry.javaagent.tooling.ClassLoaderMatcher.hasClassesNamed;
+import static net.bytebuddy.matcher.ElementMatchers.isMethod;
+import static net.bytebuddy.matcher.ElementMatchers.isPrivate;
+import static net.bytebuddy.matcher.ElementMatchers.isStatic;
+import static net.bytebuddy.matcher.ElementMatchers.named;
+import static net.bytebuddy.matcher.ElementMatchers.takesArguments;
+
+import com.google.auto.service.AutoService;
+import io.opentelemetry.instrumentation.log4j.v2_13_2.OpenTelemetryContextDataProvider;
+import io.opentelemetry.javaagent.tooling.Instrumenter;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.Map;
+import net.bytebuddy.asm.Advice;
+import net.bytebuddy.description.method.MethodDescription;
+import net.bytebuddy.description.type.TypeDescription;
+import net.bytebuddy.implementation.bytecode.assign.Assigner.Typing;
+import net.bytebuddy.matcher.ElementMatcher;
+import org.apache.logging.log4j.core.util.ContextDataProvider;
+
+@AutoService(Instrumenter.class)
+public final class Log4j2Instrumentation extends Instrumenter.Default {
+  public Log4j2Instrumentation() {
+    super("log4j2", "log4j");
+  }
+
+  @Override
+  public ElementMatcher<ClassLoader> classLoaderMatcher() {
+    return hasClassesNamed("org.apache.logging.log4j.core.util.ContextDataProvider");
+  }
+
+  @Override
+  public ElementMatcher<? super TypeDescription> typeMatcher() {
+    return named("org.apache.logging.log4j.core.impl.ThreadContextDataInjector");
+  }
+
+  @Override
+  public String[] helperClassNames() {
+    return new String[] {
+      "io.opentelemetry.instrumentation.log4j.v2_13_2.OpenTelemetryContextDataProvider"
+    };
+  }
+
+  @Override
+  public Map<? extends ElementMatcher<? super MethodDescription>, String> transformers() {
+    return Collections.singletonMap(
+        isMethod()
+            .and(isPrivate())
+            .and(isStatic())
+            .and(named("getProviders"))
+            .and(takesArguments(0)),
+        Log4j2Instrumentation.class.getName() + "$GetProvidersAdvice");
+  }
+
+  public static class GetProvidersAdvice {
+    @Advice.OnMethodExit(suppress = Throwable.class)
+    public static void onExit(
+        @Advice.Return(typing = Typing.DYNAMIC, readOnly = false)
+            List<ContextDataProvider> providers) {
+      // check if already instrumented
+      for (ContextDataProvider provider : providers) {
+        if (provider instanceof OpenTelemetryContextDataProvider) {
+          return;
+        }
+      }
+
+      List<ContextDataProvider> instrumentedProviders = new ArrayList<>(providers.size() + 1);
+      instrumentedProviders.addAll(providers);
+      instrumentedProviders.add(new OpenTelemetryContextDataProvider());
+      providers = instrumentedProviders;
+    }
+  }
+}

instrumentation/log4j/log4j-2.13.2/auto/src/test/groovy/AutoLog4j2Test.groovy

@@ -0,0 +1,18 @@
+/*
+ * Copyright The OpenTelemetry Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+class AutoLog4j2Test extends Log4j2Test {
+}

instrumentation/log4j/log4j-2.13.2/library/log4j-2.13.2-library.gradle

@@ -10,5 +10,5 @@ dependencies {
   annotationProcessor deps.autoservice
   compileOnly deps.autoservice
 
-  testAnnotationProcessor group: 'org.apache.logging.log4j', name: 'log4j-core', version: '2.13.2'
+  testImplementation project(':instrumentation:log4j:log4j-2.13.2:testing')
 }

instrumentation/log4j/log4j-2.13.2/library/src/test/groovy/LibraryLog4j2Test.groovy

@@ -0,0 +1,18 @@
+/*
+ * Copyright The OpenTelemetry Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+class LibraryLog4j2Test extends Log4j2Test {
+}

instrumentation/log4j/log4j-2.13.2/testing/log4j-2.13.2-testing.gradle

@@ -0,0 +1,15 @@
+apply from: "$rootDir/gradle/java.gradle"
+
+dependencies {
+  api project(':testing-common')
+
+  api group: 'org.apache.logging.log4j', name: 'log4j-core', version: '2.13.2'
+
+  implementation deps.guava
+
+  implementation deps.groovy
+  implementation deps.opentelemetryApi
+  implementation deps.spock
+
+  annotationProcessor group: 'org.apache.logging.log4j', name: 'log4j-core', version: '2.13.2'
+}

instrumentation/log4j/log4j-2.13.2/library/src/test/groovy/io/opentelemetry/instrumentation/log4j/v2_13_2/Log4j2Test.groovy → instrumentation/log4j/log4j-2.13.2/testing/src/main/groovy/Log4j2Test.groovy

@@ -14,24 +14,22 @@
  * limitations under the License.
  */
 
-package io.opentelemetry.instrumentation.log4j.v2_13_2
-
+import io.opentelemetry.auto.test.AgentTestRunner
 import io.opentelemetry.auto.test.utils.TraceUtils
+import io.opentelemetry.instrumentation.log4j.v2_13_2.ListAppender
 import io.opentelemetry.trace.Span
 import io.opentelemetry.trace.TracingContextUtils
 import org.apache.logging.log4j.LogManager
-import org.apache.logging.log4j.Logger
-import spock.lang.Specification
-
-class Log4j2Test extends Specification {
-
-  private static final Logger logger = LogManager.getLogger("TestLogger")
 
+abstract class Log4j2Test extends AgentTestRunner {
   def cleanup() {
     ListAppender.get().clearEvents()
   }
 
   def "no ids when no span"() {
+    given:
+    def logger = LogManager.getLogger("TestLogger")
+
     when:
     logger.info("log message 1")
     logger.info("log message 2")
@@ -52,6 +50,9 @@ class Log4j2Test extends Specification {
   }
 
   def "ids when span"() {
+    given:
+    def logger = LogManager.getLogger("TestLogger")
+
     when:
     Span span1
     TraceUtils.runUnderTrace("test") {

instrumentation/log4j/log4j-2.13.2/library/src/test/java/io/opentelemetry/instrumentation/log4j/v2_13_2/ListAppender.java → instrumentation/log4j/log4j-2.13.2/testing/src/main/java/io/opentelemetry/instrumentation/log4j/v2_13_2/ListAppender.java

@@ -41,7 +41,7 @@ public static ListAppender get() {
 
   private static final ListAppender INSTANCE = new ListAppender();
 
-  private final List<LogEvent> events = Collections.synchronizedList(new ArrayList<>());
+  private final List<LogEvent> events = Collections.synchronizedList(new ArrayList<LogEvent>());
 
   public ListAppender() {
     super("ListAppender", null, null, true, Property.EMPTY_ARRAY);

settings.gradle

@@ -126,7 +126,9 @@ include ':instrumentation:kubernetes-client-7.0'
 include ':instrumentation:lettuce:lettuce-4.0'
 include ':instrumentation:lettuce:lettuce-5.0'
 include ':instrumentation:lettuce:lettuce-5.1'
+include ':instrumentation:log4j:log4j-2.13.2:auto'
 include ':instrumentation:log4j:log4j-2.13.2:library'
+include ':instrumentation:log4j:log4j-2.13.2:testing'
 include ':instrumentation:logback:logback-1.0.0:auto'
 include ':instrumentation:logback:logback-1.0.0:library'
 include ':instrumentation:logback:logback-1.0.0:testing'