Logging in a clustered environment using Log4j

Logging using Socket Appender.

The logs should be stored in a centralized machine or sever when the application is stored in a clustered environment. Let’s get a scenario where every information level of logs goes in a clustered machine and error level log go in a server or centralized machine. So every cluster will have an information level log and if an error occurs it will show in a centralized machine.

There are four classes (Class1, Class2, Class3, Class4) these classes behave as a clustered application and ClassMain which contain the main method behave as a manager of this cluster. This cluster means class 1 2 3 4 will store the info level logs through RolingFileAppender, show the message in the console using ConsoleAppender and send the error level logs to a centralized machine using SocketAppender.

log4j.xml is the file which is defined in the application; every cluster will have the same property file and log4j-server.xml will be deployed in a centralized machine.

The command for starting socket server:-

java -classpath {Jar Path}\jars\log4j-1.2.17.jar org.apache.log4j.net.SimpleSocketServer

4712 {property file path}\log4j-server.properties 

	package com.sun.log.a;
	import org.apache.log4j.Logger;
	import com.sun.log.main.ClassMain;
	/**
	* Class1 containing log method which calls log method of main class.
	*
	* @author Suraj Bhambhani
	*
	*/
	public class Class1 {
	static Logger logger = Logger.getLogger("Class1");
	/**
	* Create logs for Class1 logger
	*
	* @return Logger
	*/
	public static Logger Log() {
	ClassMain.log(logger);
	return logger;
	}
	}

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	package com.sun.log.a;
	import org.apache.log4j.Logger;
	import com.sun.log.main.ClassMain;
	/**
	* Class2 containing log method which calls log method of main class.
	*
	* @author Suraj Bhambhani
	*
	*/
	public class Class2 {
	static Logger logger = Logger.getLogger("Class2");
	/**
	* Create logs for Class1 logger
	*
	* @return Logger
	*/
	public static Logger Log() {
	ClassMain.log(logger);
	return logger;
	}
	}

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	package com.sun.log.b;
	import org.apache.log4j.Logger;
	import com.sun.log.main.ClassMain;
	/**
	* Class3 containing log method which calls log method of main class.
	*
	* @author Suraj Bhambhani
	*
	*/
	public class Class3 {
	static Logger logger = Logger.getLogger("Class3");
	/**
	* Create logs for Class3 logger
	*
	* @return Logger
	*/
	public static Logger Log() {
	ClassMain.log(logger);
	return logger;
	}
	}

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	package com.sun.log.b;
	import org.apache.log4j.Logger;
	import com.sun.log.main.ClassMain;
	/**
	* Class4 containing log method which calls log method of main class.
	*
	* @author Suraj Bhambhani
	*
	*/
	public class Class4 {
	static Logger logger = Logger.getLogger("Class4");
	/**
	* Create logs for Class4 logger
	*
	* @return Logger
	*/
	public static Logger Log() {
	ClassMain.log(logger);
	return logger;
	}
	}

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	package com.sun.log.main;
	import java.text.SimpleDateFormat;
	import java.util.Date;
	import org.apache.log4j.Logger;
	import com.sun.log.a.Class1;
	import com.sun.log.a.Class2;
	import com.sun.log.b.Class3;
	import com.sun.log.b.Class4;
	/**
	* ClassMain containing main method which calls all classes logs.
	*
	* @author Suraj Bhambhani
	*
	*/
	public class ClassMain {
	static SimpleDateFormat sd = new SimpleDateFormat("HH:mm:ss.SSS");
	static Logger logger = Logger.getLogger(ClassMain.class);
	/**
	* Iterating to get all logs from the classes
	*
	* @param args
	*/
	public static void main(String[] args) {
	for (int i = 0; i < 20; i++) {
	Class1.Log();
	Class2.Log();
	Class3.Log();
	Class4.Log();
	}
	}
	/**
	* Generic log method which log.
	*
	* @param logger
	*/
	public static void log(Logger logger) {
	logger.error(logger.getName() + " Type Error "
	+ sd.format(new Date()).toString());
	logger.info(logger.getName() + " Type Info "
	+ sd.format(new Date()).toString());
	logger.trace(logger.getName() + " Type Trace "
	+ sd.format(new Date()).toString());
	logger.warn(logger.getName() + " Type Warn "
	+ sd.format(new Date()).toString());
	}
	}

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	<?xml version="1.0" encoding="UTF-8" ?>
	<!DOCTYPE log4j:configuration SYSTEM "log4j.dtd">
	<log4j:configuration debug="true"
	xmlns:log4j='http://jakarta.apache.org/log4j/'>
	<!--Socket appender for sending the logs to remote machine -->
	<appender name="socketAppender" class="org.apache.log4j.net.SocketAppender">
	<param name="Port" value="4712" />
	<param name="RemoteHost" value="localhost" />
	<param name="ReconnectionDelay" value="60000" />
	</appender>
	<!-- Console appender to print the logs in remote machine console -->
	<appender name="consoleAppender" class="org.apache.log4j.ConsoleAppender">
	<layout class="org.apache.log4j.PatternLayout">
	<param name="ConversionPattern" value="%-5p [%d] [%t] %c %m%n" />
	</layout>
	</appender>
	<!-- Generate a file using rolling file appender of a particular logger -->
	<appender name="fileAppender" class="org.apache.log4j.RollingFileAppender">
	<param name="Threshold" value="ALL" />
	<param name="append" value="true" />
	<param name="file" value="/Log/Local.log" />
	<layout class="org.apache.log4j.PatternLayout">
	<param name="ConversionPattern" value="%-5p [%d] [%t] %c %m%n" />
	</layout>
	</appender>
	<!-- Sending the logs to the server machine by using socket appender -->
	<logger name="Class1" additivity="false">
	<level value="ERROR" />
	<appender-ref ref="socketAppender" />
	</logger>
	<logger name="Class2" additivity="false">
	<level value="ERROR" />
	<appender-ref ref="socketAppender" />
	</logger>
	<!-- Root for defining the root work which is to be happened like console
	appender will work for everything -->
	<root>
	<appender-ref ref="consoleAppender" />
	<appender-ref ref="fileAppender" />
	</root>
	</log4j:configuration>

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	<?xml version="1.0" encoding="UTF-8" ?>
	<!DOCTYPE log4j:configuration SYSTEM "log4j.dtd">
	<log4j:configuration debug="true"
	xmlns:log4j='http://jakarta.apache.org/log4j/'>
	<!-- Console appender to print the logs in remote machine console -->
	<appender name="consoleAppender" class="org.apache.log4j.ConsoleAppender">
	<layout class="org.apache.log4j.PatternLayout">
	<param name="ConversionPattern" value="%-5p [%d] [%t] %c %m%n" />
	</layout>
	</appender>
	<!-- Generate a file using rolling file appender of a particular logger -->
	<appender name="fileAppender1" class="org.apache.log4j.RollingFileAppender">
	<param name="Threshold" value="ALL" />
	<param name="file" value="/Log/Desk1.log" />
	<layout class="org.apache.log4j.PatternLayout">
	<param name="ConversionPattern" value="%-5p [%d] [%t] %c %m%n" />
	</layout>
	</appender>
	<appender name="fileAppender2" class="org.apache.log4j.RollingFileAppender">
	<param name="Threshold" value="ALL" />
	<param name="file" value="/Log/Desk2.log" />
	<layout class="org.apache.log4j.PatternLayout">
	<param name="ConversionPattern" value="%-5p [%d] [%t] %c %m%n" />
	</layout>
	</appender>
	<!-- Catch the logs sent by a socket appender and perform the operation
	by calling the appropriate appender -->
	<logger name="Class1" additivity="false">
	<appender-ref ref="fileAppender1" />
	</logger>
	<logger name="Class2" additivity="false">
	<appender-ref ref="fileAppender2" />
	</logger>
	<!-- Root for defining the root work which is to be happened like console
	appender will work for everything -->
	<root>
	<appender-ref ref="consoleAppender" />
	</root>
	</log4j:configuration>

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References

http://logging.apache.org/log4j/1.2/apidocs/org/apache/log4j/net/SocketAppender.html