Examples

SLF4J

pom.xml

<dependencies>
  <dependency>
    <groupId>ch.qos.logback</groupId>
    <artifactId>logback-classic</artifactId>
    <version>1.2.3</version>
  </dependency>
  <dependency>
    <groupId>net.logstash.logback</groupId>
    <artifactId>logstash-logback-encoder</artifactId>
    <version>5.1</version>
  </dependency>
  <dependency>
    <groupId>org.slf4j</groupId>
    <artifactId>slf4j-api</artifactId>
    <version>1.7.25</version>
  </dependency>
</dependencies>

logback.xml

<configuration>
  <appender name="stdout_json" class="ch.qos.logback.core.ConsoleAppender">
    <encoder class="net.logstash.logback.encoder.LogstashEncoder" />
  </appender>
  <root level="info">
    <appender-ref ref="stdout_json" />
  </root>
</configuration>

Issues with long log messages

The max log message size in Docker is 16KB, so if it will be split into parts if it's bigger. Fluentd dosen't support this, so we recommend making stack traces shorter. Read more about this on github.com/logstash.

<configuration>
   <appender name="stdout_json" class="ch.qos.logback.core.ConsoleAppender">
      <encoder class="net.logstash.logback.encoder.LogstashEncoder">
         <throwableConverter class="net.logstash.logback.stacktrace.ShortenedThrowableConverter">
            <maxDepthPerThrowable>30</maxDepthPerThrowable>
            <exclude>java\.util\.concurrent\..*</exclude>
            <exclude>org\.apache\.tomcat\..*</exclude>
            <exclude>org\.apache\.coyote\..*</exclude>
            <exclude>org\.apache\.catalina\..*</exclude>
            <exclude>org\.springframework\.web\..*</exclude>
         </throwableConverter>
      </encoder>
   </appender>
   <root level="info">
      <appender-ref ref="stdout_json"/>
   </root>
</configuration>

Log4j2

pom.xml

<dependencies>
  <dependency>
    <groupId>org.apache.logging.log4j</groupId>
    <artifactId>log4j-api</artifactId>
    <version>2.17.2</version>
  </dependency>
  <dependency>
    <groupId>org.apache.logging.log4j</groupId>
    <artifactId>log4j-core</artifactId>
    <version>2.17.2</version>
  </dependency>
  <dependency>
    <groupId>org.apache.logging.log4j</groupId>
    <artifactId>log4j-layout-template-json</artifactId>
    <version>2.17.2</version>
  </dependency>
  <dependency>
    <groupId>org.apache.logging.log4j</groupId>
    <artifactId>log4j-slf4j-impl</artifactId>
    <version>2.17.2</version>
  </dependency>
  <dependency>
    <groupId>org.slf4j</groupId>
    <artifactId>slf4j-api</artifactId>
    <version>1.7.25</version>
  </dependency>
</dependencies>

log4j2.xml

<?xml version="1.0" encoding="UTF-8"?>
<Configuration status="INFO">
    <Appenders>
        <Console name="ConsoleAppender" target="SYSTEM_OUT">
          <JsonTemplateLayout templateUri="classpath:LogstashJsonEventLayoutV1.json" stackTraceEnabled="true"/>
        </Console>
    </Appenders>
    <Loggers>
        <Root level="info">
            <AppenderRef ref="ConsoleAppender"/>
        </Root>
    </Loggers>
</Configuration>

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Last update: 2022-12-02
Created: 2019-09-10