61 lines
1.7 KiB
Markdown
61 lines
1.7 KiB
Markdown
# Log4j 2 Integration
|
|
|
|
This module integrates instrumentation with Log4j 2 by injecting the trace ID and span ID from a
|
|
mounted span into
|
|
Log4j's [context data](https://logging.apache.org/log4j/2.x/manual/thread-context.html).
|
|
|
|
**Note**: Depending on your application, you may run into a [critical bug](https://issues.apache.org/jira/browse/LOG4J2-2838)
|
|
with Log4j 2.13.2. If log messages show a `NullPointerException` when adding this instrumentation,
|
|
please update to 2.13.3 or higher. The only change between 2.13.2 and 2.13.3 is the fix to this
|
|
issue.
|
|
|
|
To use it, just add the module to your application's runtime classpath.
|
|
|
|
**Maven**
|
|
|
|
```xml
|
|
|
|
<dependencies>
|
|
<dependency>
|
|
<groupId>io.opentelemetry.instrumentation</groupId>
|
|
<artifactId>opentelemetry-log4j-2.13.2</artifactId>
|
|
<version>0.17.0-alpha</version>
|
|
<scope>runtime</scope>
|
|
</dependency>
|
|
</dependencies>
|
|
```
|
|
|
|
**Gradle**
|
|
|
|
```kotlin
|
|
dependencies {
|
|
runtimeOnly("io.opentelemetry.instrumentation:opentelemetry-log4j-2.13.2:0.17.0-alpha")
|
|
}
|
|
```
|
|
|
|
Log4j will automatically pick up our integration and will have these keys added to the context when
|
|
a log statement is made when a span is active.
|
|
|
|
- `trace_id`
|
|
- `span_id`
|
|
- `trace_flags`
|
|
|
|
You can use these keys when defining an appender in your `log4j.xml` configuration, for example
|
|
|
|
```xml
|
|
<?xml version="1.0" encoding="UTF-8"?>
|
|
<Configuration>
|
|
<Appenders>
|
|
<Console name="Console" target="SYSTEM_OUT">
|
|
<PatternLayout
|
|
pattern="%d{HH:mm:ss.SSS} [%t] %-5level %logger{36} trace_id=%X{trace_id} span_id=%X{span_id} trace_flags=%X{trace_flags} - %msg%n"/>
|
|
</Console>
|
|
</Appenders>
|
|
<Loggers>
|
|
<Root>
|
|
<AppenderRef ref="Console" level="All"/>
|
|
</Root>
|
|
</Loggers>
|
|
</Configuration>
|
|
```
|