Java TraceId and SpanId Injection into Logs Configuration

This page describes how to configure spanId and traceId data injection into user logs in Java applications.

Log4j instrumentation

1. Add instrumented Log4j2 and OpenTelemetry-api libraries into the project dependencies:
   • Maven projects

     <dependencies>
         <dependency>
             <groupId>io.opentelemetry.instrumentation</groupId>
             <artifactId>opentelemetry-log4j-context-data-2.17-autoconfigure</artifactId>
             <version>2.6.0-alpha</version>
             <scope>runtime</scope>
         </dependency>
     </dependencies>
   • Gradle projects

     dependencies {
         runtimeOnly("io.opentelemetry.instrumentation:opentelemetry-log4j-context-data-2.17-autoconfigure:2.6.0-alpha")
     }
2. Update the log4j2.xml configuration file, typically stored in resources directory, with traceId, spanId, and sampled keys. The following is an example configuration.

   <?xml version="1.0" encoding="UTF-8"?>
   <Configuration status="WARN">
       <Appenders>
           <Console name="Console" target="SYSTEM_OUT">
               <PatternLayout pattern="%d{HH:mm:ss.SSS} [%t] %-5level %logger{36} traceId: %X{trace_id} spanId: %X{span_id} - %msg%n" />
           </Console>
       </Appenders>
       <Loggers>
           <Root level="All" >
               <AppenderRef ref="Console"/>
           </Root>
       </Loggers>
   </Configuration>

Logback instrumentation

1. Add instrumented logback library into the project dependencies:
   • Maven projects

     <dependencies>
         <dependency>
             <groupId>io.opentelemetry.instrumentation</groupId>
             <artifactId>opentelemetry-logback-mdc-1.0</artifactId>
             <version>2.6.0-alpha</version>
             <scope>runtime</scope>
         </dependency>
     </dependencies>
   • Gradle projects

     dependencies {
         runtimeOnly("io.opentelemetry.instrumentation:opentelemetry-logback-mdc-1.0:2.6.0-alpha")
     }
2. Update the logback.xml configuration file, typically stored in the resources directory, with traceId, spanId, and sampled keys. The following is an example configuration.

   <?xml version="1.0" encoding="UTF-8" ?>
   <configuration>
       <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
           <encoder>
               <pattern><![CDATA[%date{HH:mm:ss.SSS} [%thread] %-5level %logger{15}#%line %X{req.requestURI} traceId: %X{trace_id} spanId: %X{span_id} %msg\n]]></pattern>
           </encoder>
       </appender>
   
       <appender name="OTEL" class="io.opentelemetry.instrumentation.logback.v1_0.OpenTelemetryAppender">
           <appender-ref ref="STDOUT" />
       </appender>
   
       <root>
           <level value="DEBUG" />
           <appender-ref ref="STDOUT" />
       </root>
   
   </configuration>

note

For more details, refer to the Logger MDC auto-instrumentation.