How to roll the log file on startup in logback

Question

I would like to configure logback to do the following.

• Log to a file
• Roll the file when it reaches 50MB
• Only keep 7 days worth of logs
• On startup always generate a new file (do a roll)

I have it all working except for the last item, startup roll. Does anyone know how to achieve that? Here's the config...

  <appender name="File" class="ch.qos.logback.core.rolling.RollingFileAppender">

    <layout class="ch.qos.logback.classic.PatternLayout">
      <Pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg \(%file:%line\)%n</Pattern>
    </layout>

    <File>server.log</File>

    <rollingPolicy class="ch.qos.logback.core.rolling.TimeBasedRollingPolicy">
      <FileNamePattern>server.%d{yyyy-MM-dd}.log</FileNamePattern>
      <!-- keep 7 days' worth of history -->
      <MaxHistory>7</MaxHistory>

      <TimeBasedFileNamingAndTriggeringPolicy class="ch.qos.logback.core.rolling.SizeAndTimeBasedFNATP">
        <MaxFileSize>50MB</MaxFileSize>
      </TimeBasedFileNamingAndTriggeringPolicy>

    </rollingPolicy>
  </appender>

Solution 1

None of the other suggestions was appropriate for my situation. I didn't want to use a size-and-time-based solution, because it requires configuring a MaxFileSize, and we are using a strictly time-based policy. Here is how I accomplished rolling the file on startup with a TimeBasedRollingPolicy:

@NoAutoStart
public class StartupTimeBasedTriggeringPolicy<E> 
        extends DefaultTimeBasedFileNamingAndTriggeringPolicy<E> {

    @Override
    public void start() {
        super.start();
        nextCheck = 0L;
        isTriggeringEvent(null, null);
        try {
            tbrp.rollover();
        } catch (RolloverFailure e) {
            //Do nothing
        }
    }

}

The trick is to set the nextCheck time to 0L, so that isTriggeringEvent() will think it's time to roll the log file over. It will thus execute the code necessary to calculate the filename, as well as conveniently resetting the nextCheck time value. The subsequent call to rollover() causes the log file to be rolled. Since this only happens at startup, it is a more optimal solution than the ones that perform a comparison inside isTriggerEvent(). However small that comparison, it still degrades performance slightly when executed on every log message. This also forces the rollover to occur immediately at startup, instead of waiting for the first log event.

The @NoAutoStart annotation is important to prevent Joran from executing the start() method before all the other initialisation is complete. Otherwise, you get a NullPointerException.

Here is the config:

  <!-- Daily rollover appender that also appends timestamp and rolls over on startup -->
  <appender name="startupDailyRolloverAppender" class="ch.qos.logback.core.rolling.RollingFileAppender">
    <file>${LOG_FILE}</file>
    <rollingPolicy class="ch.qos.logback.core.rolling.TimeBasedRollingPolicy">
      <fileNamePattern>${LOG_FILE}.%d{yyyyMMdd}_%d{HHmmss,aux}</fileNamePattern>
      <TimeBasedFileNamingAndTriggeringPolicy class="my.package.StartupTimeBasedTriggeringPolicy" />
    </rollingPolicy>
    <encoder>
      <pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n</pattern>
    </encoder>
  </appender> 

Hope this helps!

Solution 2

For a solution using already existing components the logback suggests the uniquely named files: http://logback.qos.ch/manual/appenders.html#uniquelyNamed

During the application development phase or in the case of short-lived applications, e.g. batch applications, it is desirable to create a new log file at each new application launch. This is fairly easy to do with the help of the <timestamp> element.

<?xml version="1.0" encoding="UTF-8"?>
<configuration>
    <timestamp key="startTimestamp" datePattern="yyyyMMddHHmmssSSS"/>
    <appender name="File"
    class="ch.qos.logback.core.rolling.RollingFileAppender">
        <layout class="ch.qos.logback.classic.PatternLayout">
            <Pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg \(%file:%line\)%n</Pattern>
        </layout>

        <file>server-${startTimestamp}.log</file>

        <rollingPolicy class="ch.qos.logback.core.rolling.TimeBasedRollingPolicy">
            <FileNamePattern>server-${startTimestamp}-%d{yyyy-MM-dd}-%i.log</FileNamePattern>
            <!-- keep 7 days' worth of history -->
            <MaxHistory>7</MaxHistory>

            <TimeBasedFileNamingAndTriggeringPolicy
            class="ch.qos.logback.core.rolling.SizeAndTimeBasedFNATP">
                <MaxFileSize>1KB</MaxFileSize>
            </TimeBasedFileNamingAndTriggeringPolicy>
        </rollingPolicy>
    </appender>
    <root level="DEBUG">
        <appender-ref ref="File" />
    </root>
</configuration>

---

UPDATED for logback-1.2.1

<?xml version="1.0" encoding="UTF-8"?>
<configuration>
    <timestamp key="startTimestamp" datePattern="yyyyMMddHHmmssSSS"/>
    <appender name="File"
    class="ch.qos.logback.core.rolling.RollingFileAppender">
        <layout class="ch.qos.logback.classic.PatternLayout">
            <Pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg \(%file:%line\)%n</Pattern>
        </layout>

        <file>server-${startTimestamp}.log</file>

        <rollingPolicy class="ch.qos.logback.core.rolling.SizeAndTimeBasedRollingPolicy">
            <fileNamePattern>server-${startTimestamp}-%d{yyyy-MM-dd}-%i.log</fileNamePattern>
            <maxFileSize>10MB</maxFileSize>
            <!-- keep 7 days' worth of history -->
            <maxHistory>7</maxHistory>
            <totalSizeCap>20GB</totalSizeCap>
        </rollingPolicy>
    </appender>
    <root level="DEBUG">
        <appender-ref ref="File" />
    </root>
</configuration>

Solution 3

I found another solution for rolling the logFile once, when the application starts.

I use logback's RollingFileAppender with logback's FixedWindowRollingPolicy and my own implementation of a TriggeringPolicy<E>.

The FixedWindowRollingPolicy gets the fileNamePattern for the new logFile, where %1 is the new number of the file. The maxIndex stands for the maximum number of my "history". More information: FixedWindowRollingPolicy

My implementations TriggeringPolicy returns true for the first time, when isTriggeringEvent(...) gets called. So the WindowRollingPolicy rolls over the logfiles, when the Policy gets called the first time, and afterwards it will not roll over again.

The xml-configuration for the RollingFileAppender:

<configuration>
    ...
    <appender name="FILE_APPENDER" class="ch.qos.logback.core.rolling.RollingFileAppender">
        <file>logFile.log</file>

        <rollingPolicy class="ch.qos.logback.core.rolling.FixedWindowRollingPolicy">
            <fileNamePattern>logFile.%i.log</fileNamePattern>
            <minIndex>1</minIndex>
            <maxIndex>4</maxIndex>
        </rollingPolicy>

        <triggeringPolicy class="my.classpath.RollOncePerSessionTriggeringPolicy"/>
    </appender>
...
</configuration>

The TriggeringPolicy:

package my.classpath;

import ch.qos.logback.core.rolling.TriggeringPolicyBase;

import java.io.File;

public class RollOncePerSessionTriggeringPolicy<E> extends TriggeringPolicyBase<E> {
    private static boolean doRolling = true;

    @Override
    public boolean isTriggeringEvent(File activeFile, E event) {
        // roll the first time when the event gets called
        if (doRolling) {
            doRolling = false;
            return true;
        }
        return false;
    }
}

Solution 4

It works for me, using the following class as timeBasedFileNamingAndTriggeringPolicy :

import java.io.File;
import java.util.concurrent.atomic.AtomicBoolean;

import ch.qos.logback.core.joran.spi.NoAutoStart;
import ch.qos.logback.core.rolling.SizeAndTimeBasedFNATP;

@NoAutoStart
public class Trigger<E> extends SizeAndTimeBasedFNATP<E>
{
    private final AtomicBoolean trigger = new AtomicBoolean();

    public boolean isTriggeringEvent(final File activeFile, final E event) {
        if (trigger.compareAndSet(false, true) && activeFile.length() > 0) {
            String maxFileSize = getMaxFileSize();
            setMaxFileSize("1");
            super.isTriggeringEvent(activeFile, event);
            setMaxFileSize(maxFileSize);
            return true;
        }
        return super.isTriggeringEvent(activeFile, event);
    }
}

Solution 5

Overriding the isTriggeringEvent() method in ch.qos.logback.core.rolling.SizeAndTimeBasedFNATP should work nicely. Just return 'true' the first time isTriggeringEvent() method is called.

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