在logback中创建后备附加程序？

Question

In case an appender fails to log a message, I'd like to catch the log and use "fallback appender" instead. Is that possible?

Something like this (I know STDOUT wont fail)

<appender name="APPENDER" class="ch.qos.logback.core.FooAppender">
          <!-- whatever -->
</appender>

<appender name="FALLBACK_APPENDER" class="...FallbackAppender">
         <failingAppender>APPENDER</failingAppender>
</appender>

Answer 1

May be rude way of making this work is as follows.

Say suppose your appender is in package com.kp.logback.

You have custom appender which does some processing and logs on some file/db. while doing that operation it failed. you can log the messsage, as below.

public class KPAppender extends UnsynchronizedAppenderBase<ILoggingEvent>{

private static final Logger LOG = LoggerFactory.getLogger(KPAppender.class);

@Override
protected void append(ILoggingEvent eventObject) {

//try something here to process message
  if fails catch block Log message 

    if(eventObject.getLevel()== Level.DEBUG){
        LOG.debug(eventObject.getMessage());
    }

}

}

Create another Fallback appender with loback.xml configuration as below.

    <appender name="FALLBACK_APPENDER" class="...FallbackAppender">

    </appender>

<logger name="com.kp.logback">
        <level value="trace" />
        <appender-ref ref="FALLBACK_APPENDER" />
    </logger>