how to config "LogstashEncoder" in logback?

To configure the LogstashEncoder in logback, you need to follow these steps:

1. Add the following dependency to your project's pom.xml file:

<dependency>
    <groupId>net.logstash.logback</groupId>
    <artifactId>logstash-logback-encoder</artifactId>
    <version>6.6</version>
</dependency>

Note: You can change the version number to match your project's requirements.

2. Add the following configuration to your logback.xml file:

<appender name="logstash" class="ch.qos.logback.core.ConsoleAppender">
    <encoder class="net.logstash.logback.encoder.LogstashEncoder"/>
</appender>

3. Customize the encoder configuration as per your needs:

<encoder class="net.logstash.logback.encoder.LogstashEncoder">
    <customFields>{"application":"myApp"}</customFields>
    <fieldNames>
        <timestamp>time</timestamp>
        <message>msg</message>
        <level>severity</level>
    </fieldNames>
</encoder>

In this example, we have added a custom field "application" and changed the field names for the timestamp, message, and log level.

Note: You can refer to the official documentation for more customization options.