Here are a few logback.xml examples that are used in my projects, just for sharing.
P.S Tested with Logback 1.2.3
1. Send logs to Console
All logging will be redirected to console.
logback.xml
<configuration>
<appender name="CONSOLE" class="ch.qos.logback.core.ConsoleAppender">
<layout class="ch.qos.logback.classic.PatternLayout">
<Pattern>
%d{HH:mm:ss.SSS} [%t] %-5level %logger{36} - %msg%n
</Pattern>
</layout>
</appender>
<logger name="com.favtuts" level="debug" additivity="false">
<appender-ref ref="CONSOLE"/>
</logger>
<root level="error">
<appender-ref ref="CONSOLE"/>
</root>
</configuration>
2. Send logs to File + Rotate File
2.1 All logging will be redirected to a file logs/app.log. Furthermore, this log file will be archived daily or when the file size is larger than 10MB.
logback.xml
<configuration>
<property name="HOME_LOG" value="logs/app.log"/>
<appender name="FILE-ROLLING" class="ch.qos.logback.core.rolling.RollingFileAppender">
<file>${HOME_LOG}</file>
<rollingPolicy class="ch.qos.logback.core.rolling.SizeAndTimeBasedRollingPolicy">
<fileNamePattern>logs/archived/app.%d{yyyy-MM-dd}.%i.log.gz</fileNamePattern>
<!-- each archived file, size max 10MB -->
<maxFileSize>10MB</maxFileSize>
<!-- total size of all archive files, if total size > 20GB, it will delete old archived file -->
<totalSizeCap>20GB</totalSizeCap>
<!-- 60 days to keep -->
<maxHistory>60</maxHistory>
</rollingPolicy>
<encoder>
<pattern>%d %p %c{1.} [%t] %m%n</pattern>
</encoder>
</appender>
<logger name="com.favtuts" level="debug" additivity="false">
<appender-ref ref="FILE-ROLLING"/>
</logger>
<root level="error">
<appender-ref ref="FILE-ROLLING"/>
</root>
</configuration>
2.2 Below SizeAndTimeBasedFNATP example is deprecated, it may still work, but it is better to use the above new SizeAndTimeBasedRollingPolicy example.
logback.xml
<?xml version="1.0" encoding="UTF-8"?>
<configuration>
<property name="DEV_HOME" value="c:/logs" />
<appender name="FILE-AUDIT"
class="ch.qos.logback.core.rolling.RollingFileAppender">
<file>${DEV_HOME}/debug.log</file>
<encoder class="ch.qos.logback.classic.encoder.PatternLayoutEncoder">
<Pattern>
%d{yyyy-MM-dd HH:mm:ss} - %msg%n
</Pattern>
</encoder>
<rollingPolicy class="ch.qos.logback.core.rolling.TimeBasedRollingPolicy">
<!-- rollover daily -->
<fileNamePattern>${DEV_HOME}/archived/debug.%d{yyyy-MM-dd}.%i.log</fileNamePattern>
<timeBasedFileNamingAndTriggeringPolicy
class="ch.qos.logback.core.rolling.SizeAndTimeBasedFNATP">
<maxFileSize>10MB</maxFileSize>
</timeBasedFileNamingAndTriggeringPolicy>
</rollingPolicy>
</appender>
<logger name="com.favtuts" level="debug"
additivity="false">
<appender-ref ref="FILE-AUDIT" />
</logger>
<root level="error">
<appender-ref ref="FILE-AUDIT" />
</root>
</configuration>
3. Send error logs to email
logback.xml
<configuration>
<appender name="CONSOLE" class="ch.qos.logback.core.ConsoleAppender">
<layout class="ch.qos.logback.classic.PatternLayout">
<Pattern>
%d{HH:mm:ss.SSS} [%t] %-5level %logger{36} - %msg%n
</Pattern>
</layout>
</appender>
<appender name="EMAIL" class="ch.qos.logback.classic.net.SMTPAppender">
<smtpHost>smtp.mailgun.org</smtpHost>
<smtpPort>25</smtpPort>
<username>123</username>
<password>123</password>
<to>TO_EMAIL</to>
<to>RO_ANOTHER_EMAIL</to>
<from>FROM_EMAIL</from>
<subject>TESTING: %logger{20} - %m</subject>
<layout class="ch.qos.logback.classic.html.HTMLLayout"/>
</appender>
<logger name="com.favtuts" level="error" additivity="false">
<appender-ref ref="EMAIL"/>
</logger>
<root level="error">
<appender-ref ref="CONSOLE"/>
</root>
</configuration>
To send email, we need this javax.mail
pom.xml
<dependency> <groupId>com.sun.mail</groupId> <artifactId>javax.mail</artifactId> <version>1.6.2</version> </dependency>
5. Logs Asynchronously
This make logging faster.
logback.xml
<configuration>
<appender name="FILE-ROLLING" class="ch.qos.logback.core.rolling.RollingFileAppender">
<!-- //... -->
</appender>
<appender name="ASYNC" class="ch.qos.logback.classic.AsyncAppender">
<appender-ref ref="FILE-ROLLING" />
</appender>
<root level="debug">
<appender-ref ref="ASYNC"/>
</root>
</configuration>
6. SiftingAppender
Send logs to a separate log file, the log file name is defined at runtime, via MDC.
logback.xml
<configuration>
<property name="DEV_HOME" value="c:/logs" />
<appender name="FILE-THREAD" class="ch.qos.logback.classic.sift.SiftingAppender">
<discriminator>
<key>logFileName</key>
<defaultValue>head0</defaultValue>
</discriminator>
<sift>
<appender name="FILE-${logFileName}"
class="ch.qos.logback.core.rolling.RollingFileAppender">
<file>${DEV_HOME}/${logFileName}.log</file>
<encoder class="ch.qos.logback.classic.encoder.PatternLayoutEncoder">
<Pattern>
%d{yyyy-MM-dd HH:mm:ss} [%thread] %level %logger{35} - %msg%n
</Pattern>
</encoder>
<rollingPolicy
class="ch.qos.logback.core.rolling.FixedWindowRollingPolicy">
<FileNamePattern>${DEV_HOME}/${logFileName}.%i.log.zip</FileNamePattern>
<MinIndex>1</MinIndex>
<MaxIndex>10</MaxIndex>
</rollingPolicy>
<triggeringPolicy
class="ch.qos.logback.core.rolling.SizeBasedTriggeringPolicy">
<MaxFileSize>10MB</MaxFileSize>
</triggeringPolicy>
</appender>
</sift>
</appender>
<logger name="com.favtuts.web" level="debug"
additivity="false">
<appender-ref ref="FILE-THREAD" />
</logger>
<root level="error">
<appender-ref ref="FILE-THREAD" />
</root>
</configuration>
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.slf4j.MDC;
//...
public void run() {
MDC.put('logFileName', "head1");
logger.debug("hello");
MDC.remove('logFileName');
}
Note
Please refer to this complete Logback SiftingAppender example
7. Set log file name programmatically
Set the log file name ${log.name} programmatically, via System.setProperty
logback.xml
<configuration>
<property name="USER_HOME" value="/home/favtuts/ant/logs" />
<appender name="FILE-ENGINE-ERROR" class="ch.qos.logback.core.FileAppender">
<file>${USER_HOME}/${log.name}.error</file>
<encoder>
<pattern>%d{yyyy-MM-dd HH:mm:ss} [%thread] %-5level %logger{36} - %msg%n</pattern>
</encoder>
</appender>
<appender name="FILE-ENGINE" class="ch.qos.logback.core.FileAppender">
<file>${USER_HOME}/${log.name}.log</file>
<encoder>
<pattern>%d{yyyy-MM-dd HH:mm:ss} [%thread] %-5level %logger{35} - %msg%n</pattern>
</encoder>
</appender>
<logger name="com.favtuts.core" level="debug" additivity="false">
<appender-ref ref="FILE-ENGINE" />
</logger>
<root level="error">
<appender-ref ref="FILE-ENGINE-ERROR" />
</root>
</configuration>
TestRunApp.java
package com.favtuts.core;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
public class TestRunApp {
//No static, else log.name.IS_UNDEFINED.log
private final Logger logger = LoggerFactory.getLogger(TestRunApp.class);
public static void main(String[] args) {
//Set this before the logger start.
System.setProperty("log.name", "abcdefg");
TestRunApp obj = new TestRunApp();
obj.start();
}
private void start() {
logger.debug("------ Starting Ant------");
//...
}
}
Output
Debug log file path
/home/favtuts/ant/logs/abcdefg.log
Error log file path
/home/favtuts/ant/logs/abcdefg.errorNote
Please refer to this complete example Logback – Set log file name programmatically