Java – can I prefix each row of the stack trace in log4j?

When you write

logger.error("message",exception);

Log4j generates a message and a complete stack trace:

Aug  9 06:26:13 10.175.60.14 myPrefix: [error] [TP-Processor114] [my.class.Name] message : exception
at fatherOfException
at fatherof_fatherOfException
at fatherof_fatherof_fatherOfException
...

My conversion mode is

log4j.appender.syslog.layout.ConversionPattern=myPrefix: [%p] [%t] [%c] [%x] - %m%n

Then, can I use myprefix to prefix each row as follows:

Aug  9 06:26:13 10.175.60.14 myPrefix: [error] [TP-Processor114] [my.class.Name] message : exception
myPrefix    at fatherOfException
myPrefix    at fatherof_fatherOfException
myPrefix    at fatherof_fatherof_fatherOfException
    ...

When I grep my log on myprefix, I can't see the stack trace We have many different prefixes (one for each module)

Thank you in advance

Solution

Subclass throwablerenderer, for example:

import org.apache.log4j.DefaultThrowableRenderer;
import org.apache.log4j.spi.ThrowableRenderer;

public class LogThrowableRenderer implements ThrowableRenderer {

    DefaultThrowableRenderer def = new DefaultThrowableRenderer();

    @Override
    public String[] doRender(Throwable t) {
        String[] temp = def.doRender(t);
        for (int i = 0; i < temp.length; i++) {
            temp[i] = "myPrefix "+temp[i];
        }
        return temp;
    }

}

Add to log4j properties：

log4j.throwableRenderer=whatever.package.LogThrowableRenderer

This uses the existing defaultthrowablerenderer to render stack traces in a familiar way before adding prefixes, so it will include throwable classes, messages, and reasons