Add a Log4j 2.x Java agent

[lttng-ust.git] / doc / examples / java-log4j2-prog / HelloLog4j2Prog.java

diff --git a/doc/examples/java-log4j2-prog/HelloLog4j2Prog.java b/doc/examples/java-log4j2-prog/HelloLog4j2Prog.java
new file mode 100644 (file)
index 0000000..685eebf
--- /dev/null
+++ b/doc/examples/java-log4j2-prog/HelloLog4j2Prog.java
@@ -0,0 +1,76 @@
+/*
+ * SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2022 EfficiOS Inc.
+ */
+
+import org.apache.logging.log4j.Level;
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.apache.logging.log4j.core.config.Configurator;
+import org.apache.logging.log4j.core.config.builder.api.AppenderComponentBuilder;
+import org.apache.logging.log4j.core.config.builder.api.ConfigurationBuilder;
+import org.apache.logging.log4j.core.config.builder.api.ConfigurationBuilderFactory;
+import org.apache.logging.log4j.core.config.builder.api.LayoutComponentBuilder;
+import org.apache.logging.log4j.core.config.builder.api.RootLoggerComponentBuilder;
+import org.apache.logging.log4j.core.config.builder.impl.BuiltConfiguration;
+
+/**
+ * Example application using the LTTng-UST Java log4j agent.
+ *
+ * <p>
+ * To obtain LTTng trace events, you should run the following sequence of
+ * commands:
+ * </p>
+ *
+ * <ul>
+ * <li>$ lttng create</li>
+ * <li>$ lttng enable-event -l -a</li>
+ * <li>$ lttng start</li>
+ * <li>(run this program)</li>
+ * <li>$ lttng stop</li>
+ * <li>$ lttng view</li>
+ * <li>$ lttng destroy</li>
+ * </ul>
+ *
+ */
+public class HelloLog4j2Prog {
+
+       /**
+        * Application start
+        *
+        * @param args Command-line arguments
+        */
+       public static void main(String args[]) {
+
+               ConfigurationBuilder<BuiltConfiguration> builder = ConfigurationBuilderFactory.newConfigurationBuilder();
+
+               /* Layout */
+               LayoutComponentBuilder standardLayout = builder.newLayout("PatternLayout");
+               standardLayout.addAttribute("pattern", "%d [%t] %-5level: %msg%n%throwable");
+
+               /* Create a console appender */
+               AppenderComponentBuilder appenderBuilder = builder.newAppender("Stdout", "CONSOLE");
+               appenderBuilder.add(standardLayout);
+               builder.add(appenderBuilder);
+
+               /* Create an Lttng appender */
+               appenderBuilder = builder.newAppender("Lttng", "LTTNG");
+               builder.add(appenderBuilder);
+
+               /* Create a root logger with both appenders attached */
+               RootLoggerComponentBuilder rootLogger = builder.newRootLogger(Level.DEBUG);
+               rootLogger.add(builder.newAppenderRef("Stdout"));
+               rootLogger.add(builder.newAppenderRef("Lttng"));
+               builder.add(rootLogger);
+
+               Configurator.initialize(builder.build());
+
+               Logger logger = LogManager.getLogger(HelloLog4j2Prog.class);
+
+               /* Trigger some tracing events using the Log4j Logger created before. */
+               logger.info("Prog config: Hello World, the answer is " + 42);
+               logger.info("Prog config: Another info event");
+               logger.error("Prog config: An error event");
+       }
+}