Logging is one of the most important aspects of developing programs. Logs provide us with information about the behavior of programs, whether the behavior is expected or not.

Log4j is a very popular package for logging purpose written in Java. (Note: This article assumes that you are familiar with Log4j and already using Log4j.)

Sometimes, we need the logs on different machines. Let's consider that the application is running on a remote system and we need the logs on our local machine.

Hence, the following question arises.

How Can I Direct Logs to a Desirable Machine?

There are some simple steps to do this:

Change the log4j.properties files on the sender side. Use SocketAppender to direct logs to another machine. See the following log4j.properties files:

log4j.rootLogger=DEBUG, server
log4j.appender.server=org.apache.log4j.net.SocketAppender
log4j.appender.server.Port=4712
log4j.appender.server.RemoteHost=loghost
log4j.appender.server.ReconnectionDelay=10000

Modify the log4j-reciever.properties files on the reciever side. See the following file:

log4j.rootLogger=DEBUG, file
log4j.appender.file=org.apache.log4j.RollingFileAppender
log4j.appender.file.File=logfile.log
log4j.appender.file.MaxFileSize=1MB
log4j.appender.file.MaxBackupIndex=1
log4j.appender.file.layout=org.apache.log4j.PatternLayout
log4j.appender.file.layout.ConversionPattern=[%d] [%t] [%m]%n

Run the following command on the reciever side:

java -classpath log4j-path.jar org.apache.log4j.net.SimpleSocketServer 4712 log4j-reciever.properties

After this setup, run your program/application, and you will get logs at your desirable machine.