feat(javaagent-log-appender): switch to javaagent

Author: smoke

log-appender/README.md

@@ -37,6 +37,13 @@ docker-compose up
 In a separate shell, run the application
 
 ```shell
+export \
+OTEL_SERVICE_NAME=log4j-example \
+OTEL_EXPORTER_OTLP_PROTOCOL=grpc \
+OTEL_METRICS_EXPORTER=none \
+OTEL_TRACES_EXPORTER=none \
+OTEL_LOGS_EXPORTER=otlp
+
 ../gradlew run
 ```
 

log-appender/build.gradle.kts

@@ -3,8 +3,8 @@ plugins {
     id("application")
 }
 
-description = "OpenTelemetry Log Appender Example"
-val moduleName by extra { "io.opentelemetry.examples.log-appender" }
+description = "OpenTelemetry Log Appender Example using JavaAgent"
+val moduleName by extra { "io.opentelemetry.examples.javaagent-log-appender" }
 
 java {
     toolchain {
@@ -13,6 +13,8 @@ java {
     }
 }
 
+val agent = configurations.create("agent")
+
 dependencies {
     // Slf4J / logback
     implementation("org.slf4j:slf4j-api:2.0.16")
@@ -28,15 +30,24 @@ dependencies {
     implementation("org.apache.logging.log4j:log4j-core")
 
     // OpenTelemetry core
-    implementation("io.opentelemetry:opentelemetry-sdk")
-    implementation("io.opentelemetry:opentelemetry-exporter-otlp")
+    implementation("io.opentelemetry:opentelemetry-api")
     implementation("io.opentelemetry.semconv:opentelemetry-semconv")
 
     // OpenTelemetry log4j / logback appenders
     implementation("io.opentelemetry.instrumentation:opentelemetry-log4j-appender-2.17")
     implementation("io.opentelemetry.instrumentation:opentelemetry-logback-appender-1.0")
+
+    // OpenTelemetry JavaAgent
+    agent("io.opentelemetry.javaagent:opentelemetry-javaagent:2.8.0")
 }
 
 application {
     mainClass = "io.opentelemetry.example.logappender.Application"
 }
+
+
+tasks.named<JavaExec>("run") {
+    doFirst {
+        jvmArgs("-javaagent:${agent.singleFile}")
+    }
+}

log-appender/src/main/java/io/opentelemetry/example/logappender/Application.java

@@ -1,19 +1,10 @@
 package io.opentelemetry.example.logappender;
 
 import io.opentelemetry.api.GlobalOpenTelemetry;
-import io.opentelemetry.api.OpenTelemetry;
 import io.opentelemetry.api.common.AttributeKey;
 import io.opentelemetry.api.logs.Severity;
 import io.opentelemetry.api.trace.Span;
 import io.opentelemetry.context.Scope;
-import io.opentelemetry.exporter.otlp.logs.OtlpGrpcLogRecordExporter;
-import io.opentelemetry.sdk.OpenTelemetrySdk;
-import io.opentelemetry.sdk.logs.SdkLoggerProvider;
-import io.opentelemetry.sdk.logs.export.BatchLogRecordProcessor;
-import io.opentelemetry.sdk.resources.Resource;
-import io.opentelemetry.sdk.trace.SdkTracerProvider;
-import io.opentelemetry.sdk.trace.samplers.Sampler;
-import io.opentelemetry.semconv.ResourceAttributes;
 import java.util.HashMap;
 import java.util.Map;
 import java.util.logging.Level;
@@ -32,15 +23,6 @@ public class Application {
   private static final java.util.logging.Logger julLogger = Logger.getLogger("jul-logger");
 
   public static void main(String[] args) {
-    // Initialize OpenTelemetry as early as possible
-    OpenTelemetry openTelemetry = initializeOpenTelemetry();
-    // Install OpenTelemetry in log4j appender
-    io.opentelemetry.instrumentation.log4j.appender.v2_17.OpenTelemetryAppender.install(
-        openTelemetry);
-    // Install OpenTelemetry in logback appender
-    io.opentelemetry.instrumentation.logback.appender.v1_0.OpenTelemetryAppender.install(
-        openTelemetry);
-
     // Route JUL logs to slf4j
     SLF4JBridgeHandler.removeHandlersForRootLogger();
     SLF4JBridgeHandler.install();
@@ -86,7 +68,7 @@ public static void main(String[] args) {
     // existing frameworks into the OpenTelemetry Log Bridge API. These APIs
     // SHOULD NOT be used by end users in place of existing log APIs (i.e. Log4j, Slf4, JUL).
     io.opentelemetry.api.logs.Logger customAppenderLogger =
-        openTelemetry.getLogsBridge().get("custom-log-appender");
+        GlobalOpenTelemetry.get().getLogsBridge().get("custom-log-appender");
     maybeRunWithSpan(
         () ->
             customAppenderLogger
@@ -107,31 +89,6 @@ public static void main(String[] args) {
         true);
   }
 
-  private static OpenTelemetry initializeOpenTelemetry() {
-    OpenTelemetrySdk sdk =
-        OpenTelemetrySdk.builder()
-            .setTracerProvider(SdkTracerProvider.builder().setSampler(Sampler.alwaysOn()).build())
-            .setLoggerProvider(
-                SdkLoggerProvider.builder()
-                    .setResource(
-                        Resource.getDefault().toBuilder()
-                            .put(ResourceAttributes.SERVICE_NAME, "log4j-example")
-                            .build())
-                    .addLogRecordProcessor(
-                        BatchLogRecordProcessor.builder(
-                                OtlpGrpcLogRecordExporter.builder()
-                                    .setEndpoint("http://localhost:4317")
-                                    .build())
-                            .build())
-                    .build())
-            .build();
-
-    // Add hook to close SDK, which flushes logs
-    Runtime.getRuntime().addShutdownHook(new Thread(sdk::close));
-
-    return sdk;
-  }
-
   private static void maybeRunWithSpan(Runnable runnable, boolean withSpan) {
     if (!withSpan) {
       runnable.run();