Make Logback write to the console locally, but to log file on server

Question

In a web application built with Maven 3, is there a way to have Logback use either a ConsoleAppender or a RollingFileAppender depending where/how the application is running?

In production the .war file is deployed on Tomcat 7. Locally I'm running the Jetty Maven plugin for testing purposes during development.

I would like to have the logging work like this:

• When I run mvn jetty:run locally: Use ConsoleAppender
• When *.war file is deployed on production (Tomcat 7): Use RollingFileAppender

During local development it just seems very comfortable to have all log output on the console. In production I would instead prefer to log to a file: CATALINA_BASE/logs/myApp.log.

Obviously you could just use both a ConsoleAppender and a RollingFileAppender in logback.xml. But to me it seems unnecessarily redundant to have all log output on production written to STDOUT AND into a log file. Also, from the Tomcat documentation it sounds like logging to STDOUT on production is a bad practice in general.

I couldn't find any nice solutions on the web. Is there a good solution for this?

Here's my current logback.xml which always logs to STDOUT and to the desired log file:

<?xml version="1.0" encoding="UTF-8"?>
<configuration>

    <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
        <encoder>
            <pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n</pattern>
        </encoder>
    </appender>

    <appender name="FILE" class="ch.qos.logback.core.rolling.RollingFileAppender">
        <file>${catalina.base}/logs/myApp.log</file>
        <rollingPolicy class="ch.qos.logback.core.rolling.TimeBasedRollingPolicy">
            <fileNamePattern>${catalina.base}/logs/myApp.%d{yyyy-MM-dd}.log</fileNamePattern>
            <maxHistory>30</maxHistory>
        </rollingPolicy>

        <encoder>
            <pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n</pattern>
        </encoder>
    </appender>

    <logger name="com.myDomain.myApp" level="DEBUG" />

    <root level="DEBUG">
        <appender-ref ref="STDOUT" />
        <appender-ref ref="FILE" />
    </root>
</configuration>

Answer 1

You may configure your logback and add profile information in it. No changes in POM required

 <springProfile name="local">
    <root level="DEBUG">
<!-- no appenders -->
        <appender-ref ref="stdout"/>
    </root>
</springProfile>
<springProfile name="prod">
    <root level="INFO">
        <appender-ref ref="FILE_APPENDER"/>
    </root>
</springProfile>

You Might need to include below spring files as well

<include resource="org/springframework/boot/logging/logback/defaults.xml" />
<include resource="org/springframework/boot/logging/logback/console-appender.xml" />

For more info checkout logback

Answer 2

I had this same need and it turned out to be quite easy with the help of spring boot"ifulness" and conditional support available for logback. The following is a template that I came up with that could be for any app as it creates the logfile using spring.applcation.name if available, which you can define in bootstrap.properties:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE project>
<configuration>
    <if condition='isDefined("logging.path")'>
        <then>
            <!--  get application name from external properties file -->
            <property resource="bootstrap.properties" />

            <!--  set local properties here for better visibility -->
            <!--  TODO: make these profile conditional based on profiles -->
            <property name="logging.maxfilesize" value="1GB" />
            <property name="logging.maxdays" value="180" />

            <!-- Assume file strategy for appender if logging path given -->
            <appender name="FILE" class="ch.qos.logback.core.rolling.RollingFileAppender">
                <!-- Use application.log if s.a.n not defined in bootstrap.properties -->
                <file>${logging.path}/${spring.application.name:-application}.log</file>
                <rollingPolicy class="ch.qos.logback.core.rolling.TimeBasedRollingPolicy">
                    <!-- daily rollover -->
                    <fileNamePattern>${logging.path}/${spring.application.name:-application}.%d{yyyy-MM-dd}.%i.log.gz</fileNamePattern>
                    <timeBasedFileNamingAndTriggeringPolicy class="ch.qos.logback.core.rolling.SizeAndTimeBasedFNATP">
                        <!-- or whenever the file size reaches maxFileSize -->
                        <maxFileSize>${logging.maxfilesize}</maxFileSize>
                    </timeBasedFileNamingAndTriggeringPolicy>
                    <!-- keep max days' worth of history -->
                    <maxHistory>${logging.maxdays}</maxHistory>
                </rollingPolicy>
                <encoder>
                    <pattern>%date [%thread] %-5level %logger{36} - %msg%n</pattern>
                </encoder>
            </appender>
            <root>
                <appender-ref ref="FILE" />
            </root>
        </then>
        <else>
            <!-- The logging path not specified so assume console output -->
            <!-- Note: In this case we don't care about the full date just the hour minutes seconds -->
            <appender name="CON" class="ch.qos.logback.core.ConsoleAppender">
                <encoder>
                    <pattern>%d{HH:mm:ss.SSS} %-5level %logger{35} - %msg %n</pattern>
                </encoder>
            </appender>
            <root>
                <appender-ref ref="CON" />
            </root>
        </else>
    </if>

    <!-- in-house loggers -->


    <!-- 3rdparty Loggers -->

    <logger name="org.springframework">
        <level value="WARN" />
    </logger>

    <!-- default root level for everything else -->

    <root>
        <level value="INFO" />
    </root>

</configuration>

If spring boot app with starter parent, you only need add the following to your pom.xml:

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-logging</artifactId>
</dependency>
<!-- Needed for conditional logback.xml statement support - very cool stuff -->
<dependency>
    <groupId>org.codehaus.janino</groupId>
    <artifactId>janino</artifactId>
</dependency>

Answer 3

You can use profiles to switch between environment. Say you have two different logback.xml files for local and prod. Create a logback directory inside your resources directory. Inside the resources directory, create an environment specific directory. the directory name and envName inside property should match. Here is an example.

<profiles>
        <profile>
            <id>local</id>
            <activation>
                <activeByDefault>true</activeByDefault>
            </activation>
            <properties>
                <envName>local</envName>
            </properties>
        </profile>
        <profile>
            <id>prod</id>
            <properties>
                <envName>prod</envName>
            </properties>
        </profile>
</profiles>

<build>
    <finalName>kp-prj</finalName>
    <outputDirectory>${project.build.directory}/classes</outputDirectory>
    <sourceDirectory>${project.basedir}/src/main/java</sourceDirectory>
    <resources>
        <resource>
            <directory>${basedir}/src/main/java</directory>
            <includes>
                <include>**/*.class</include>
            </includes>
        </resource>
        <resource>
            <directory>src/main/resources/logback/${envName}</directory>
        </resource>
    </resources>
</build>

And while using running maven command you specify the profile.

mvn run -Plocal