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>

Answer 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!

Answer 2

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

Answer 3

The API has changed (for example setMaxFileSize no longer exists) and a lot of the stuff above doesn't seem to work, but I have something that is working for me against logback 1.1.8 (the latest at this time).

I wanted to roll on startup and roll on size, but not time. This does it:

public class RollOnStartupAndSizeTriggeringPolicy<E> extends SizeBasedTriggeringPolicy<E> {
    private final AtomicBoolean firstTime = new AtomicBoolean();

    public boolean isTriggeringEvent(final File activeFile, final E event) {
        if (firstTime.compareAndSet(false, true) && activeFile != null && activeFile.length() > 0) {
            return true;
        }
        return super.isTriggeringEvent(activeFile, event);
    }
}

With this you also need a rolling policy. FixedWindowRollingPolicy would probably do, but I don't like it because I want to keep a large number of files and it is very inefficient for that. Something that numbers incrementally up (instead of sliding like FixedWindow) would work, but that doesn't exist. As long as I am writing my own I decided to use time instead of count. I wanted to extend current logback code, but for the time based stuff the rolling and triggering policies are often combined into one class, and there is logs of nesting and circular stuff and fields with no getters, so I found that rather impossible. So I had to do a lot from scratch. I keep it simple and didn't implement features like compression - I'd love to have them but I am just trying to keep it simple.

public class TimestampRollingPolicy<E> extends RollingPolicyBase {
    private final RenameUtil renameUtil = new RenameUtil();
    private String activeFileName;
    private String fileNamePatternStr;
    private FileNamePattern fileNamePattern;

    @Override
    public void start() {
        super.start();
        renameUtil.setContext(this.context);
        activeFileName = getParentsRawFileProperty();
        if (activeFileName == null || activeFileName.isEmpty()) {
            addError("No file set on appender");
        }
        if (fileNamePatternStr == null || fileNamePatternStr.isEmpty()) {
            addError("fileNamePattern not set");
            fileNamePattern = null;
        } else {
            fileNamePattern = new FileNamePattern(fileNamePatternStr, this.context);
        }
        addInfo("Will use the pattern " + fileNamePattern + " to archive files");
    }

    @Override
    public void rollover() throws RolloverFailure {
        File f = new File(activeFileName);
        if (!f.exists()) {
            return;
        }
        if (f.length() <= 0) {
            return;
        }
        try {
            String archiveFileName = fileNamePattern.convert(new Date(f.lastModified()));
            renameUtil.rename(activeFileName, archiveFileName);
        } catch (RolloverFailure e) {
            throw e;
        } catch (Exception e) {
            throw new RolloverFailure(e.toString(), e);
        }
    }

    @Override
    public String getActiveFileName() {
        return activeFileName;
    }

    public void setFileNamePattern(String fnp) {
        fileNamePatternStr = fnp;
    }
}

And then config looks like

<appender name="FILE" class="ch.qos.logback.core.rolling.RollingFileAppender">
  <encoder>
    <pattern>%d{yyyy-MM-dd HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n</pattern>
  </encoder>
  <file>/tmp/monitor.log</file>
  <rollingPolicy class="my.log.TimestampRollingPolicy">
    <fileNamePattern>/tmp/monitor.%d{yyyyMMdd-HHmmss}.log</fileNamePattern>
  </rollingPolicy>
  <triggeringPolicy class="my.log.RollOnStartupAndSizeTriggeringPolicy">
    <maxFileSize>1gb</maxFileSize>
  </triggeringPolicy>
</appender>

if you're frustrated this is not solved natively, vote for it at

http://jira.qos.ch/browse/LOGBACK-204

http://jira.qos.ch/browse/LOGBACK-215

(it's been years, and to me this is absolutely critical functionality, although I know many other frameworks fail at it also)

Answer 4

I got the following to work (combining ideas from previous answers). Note I was dealing with size-based files, not time-based, but I am guessing the same solution works.

public class StartupSizeBasedTriggeringPolicy<E> extends ch.qos.logback.core.rolling.SizeBasedTriggeringPolicy<E> {

private final AtomicReference<Boolean> isFirstTime = new AtomicReference<Boolean>(true);

@Override
public boolean isTriggeringEvent(final File activeFile, final E event) {

    //this method appears to have side-effects so always call
    boolean result = super.isTriggeringEvent(activeFile, event);

    return isFirstTime.compareAndSet(true, false) || result;
}

}

Answer 5

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;
    }
}

Answer 6

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);
    }
}