How can the configuration of the Log4J2 Json Layout Template be done?

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The Log4J2 Json Layout Template configuration can be done by modifying the Log4J2 configuration file.

Here is an example of how to configure the Json Layout Template in Log4J2:

<?xml version="1.0" encoding="UTF-8"?>
<Configuration status="WARN">
  <Appenders>
    <Console name="Console" target="SYSTEM_OUT">
      <JsonLayout complete="false" compact="true">
          <KeyValuePair key="timestamp" value="$${date:yyyy-MM-dd HH:mm:ss.SSS}"/>
          <KeyValuePair key="level" value="$${level}"/>
          <KeyValuePair key="logger" value="$${logger}"/>
          <KeyValuePair key="message" value="$${message}"/>
          <KeyValuePair key="exception" value="$${exception}"/>
      </JsonLayout>
    </Console>
  </Appenders>
  <Loggers>
    <Root level="info">
      <AppenderRef ref="Console"/>
    </Root>
  </Loggers>
</Configuration>

In this example, we define an appender named Console that uses the JsonLayout and outputs messages to the console. The JsonLayout is configured with several KeyValuePair elements that define the fields to include in the JSON output.

The complete attribute specifies whether the JSON output should be a complete JSON object (true) or just a list of JSON objects (false). The compact attribute specifies whether to output the JSON in compact form or pretty-printed.

The KeyValuePair elements define the key-value pairs in the JSON output. The key attribute specifies the name of the field, and the value attribute specifies a Log4J2 variable that will be replaced with the actual value at runtime.

In this example, we include timestamp, level, logger, message, and exception fields in the JSON output. The timestamp field is generated using the date variable, while the other fields use built-in Log4J2 variables.

By customizing the KeyValuePair elements, you can configure the JSON output to include any fields you need.