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

I finally figure it out. I can roll by size, time and start up. Here is solution:

1st create you own class

@NoAutoStart
public class StartupSizeTimeBasedTriggeringPolicy<E> extends SizeAndTimeBasedFNATP<E> {

    private boolean started = false;

    @Override
    public boolean isTriggeringEvent( File activeFile, E event ) {
        if ( !started ) {
            nextCheck = 0L;
            return started = true;
        }

        return super.isTriggeringEvent( activeFile, event );
    };
}

2nd configure logback

<appender name="FILE" class="ch.qos.logback.core.rolling.RollingFileAppender">
    <file>${LOGS_DIR}/${FILE_NAME}.log</file>
    <encoder>
        <pattern>%d [%thread] %-5level %logger{50} - %msg%n</pattern>
    </encoder>
    <rollingPolicy class="ch.qos.logback.core.rolling.TimeBasedRollingPolicy">
        <fileNamePattern>${LOGS_DIR}/${FILE_NAME}.%d{yyyy-MM-dd}_%d{HHmmss,aux}.%i.log.zip</fileNamePattern>
        <maxHistory>30</maxHistory>
        <TimeBasedFileNamingAndTriggeringPolicy class="my.StartupSizeTimeBasedTriggeringPolicy">
            <MaxFileSize>250MB</MaxFileSize> 
        </TimeBasedFileNamingAndTriggeringPolicy>
    </rollingPolicy>
</appender>

Answer 2

Ceki's solution doesn't appear to work for me, but seems to be part way there at least.

It blows up because it can't see the rolling policy when starting the TimeBasedFileNamingAndTriggeringPolicyBase. With some hackery I got it to do some logging, and with some more I got it to observe the trigger, but then it broke again because it couldn't resolve one of the filename properties... The package is a logback one so I could get to some of the internals, to replicate some of the logic in SizeAndTimeBasedFNATP#isTriggeringEvent and call computeCurrentPeriodsHighestCounterValue. I think something along those lines might work, just haven't found the magic combination yet. I really hope I'm doing something silly, because otherwise I think it will mean either opening up some of the details for subclassing, or putting this straight into logback as another rolling/triggering policy.

logback.xml: tried various orderings of triggeringPolicy, TimeBasedFileNamingAndTriggeringPolicy inside and outside the rollingPolicy.

<appender name="FILE" class="ch.qos.logback.core.rolling.RollingFileAppender">
    <file>${LOG_DIR}/${LOG_FILE_BASE}.log</file>
    <rollingPolicy class="ch.qos.logback.core.rolling.TimeBasedRollingPolicy">
        <fileNamePattern>${LOG_DIR}/${LOG_FILE_BASE}.%d{yyyy-MM-dd}.%i.log</fileNamePattern>
        <MaxHistory>7</MaxHistory>

        <TimeBasedFileNamingAndTriggeringPolicy class="ch.qos.logback.core.rolling.RollOnStartupPolicy" />
    </rollingPolicy>

    <filter class="ch.qos.logback.classic.filter.ThresholdFilter">
        <level>INFO</level>
    </filter>

    <encoder>
        <pattern>%msg%n</pattern>
    </encoder>
</appender>

The trigger policy:

package ch.qos.logback.core.rolling;
public class RollOnStartupPolicy<E> extends SizeAndTimeBasedFNATP<E> {
private final AtomicBoolean firstTime = new AtomicBoolean(true);

    @Override
    public boolean isTriggeringEvent(File activeFile, E event) {
        if (!firstTime.get()) { // fast path
            return false;
        }

        if (firstTime.getAndSet(false)) {
            return true;
        }
        return false;
    }
}

The exception:

java.lang.NullPointerException
at  at ch.qos.logback.core.rolling.TimeBasedFileNamingAndTriggeringPolicyBase.start(TimeBasedFileNamingAndTriggeringPolicyBase.java:46)
at  at ch.qos.logback.core.rolling.SizeAndTimeBasedFNATP.start(SizeAndTimeBasedFNATP.java:36)
at  at ch.qos.logback.core.joran... [snip joran config]

Answer 3

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>

Answer 4

This solution really works, thanks a lot. However, there is one annoying glitch: when you run the program first time, the log is rolled right after it is created, when it is empty or almost empty. So I suggest a fix: check whether the log file exists and is not empty at the time the method is called. Also, one more cosmetic fix: rename the "started" variable, because it is hiding the inherited member with the same name.

@NoAutoStart
public class StartupSizeTimeBasedTriggeringPolicy<E> extends     SizeAndTimeBasedFNATP<E> {

    private boolean policyStarted;

    @Override
    public boolean isTriggeringEvent(File activeFile, E event) {
        if (!policyStarted) {
            policyStarted = true;
            if (activeFile.exists() && activeFile.length() > 0) {
                nextCheck = 0L;
                return true;
            }
        }
        return super.isTriggeringEvent(activeFile, event);
    }
}

Also, I believe it works properly with logback version 1.1.4-SNAPSHOT (I got the source and compiled it myself), but it does not fully work with 1.1.3 release. With 1.1.3, it names the files properly with the specified time zone, but rollover still happens at default time zone midnight.

Answer 5

Create your own subclass of ch.qos.logback.core.rolling.TimeBasedRollingPolicy and override its start

public class MyPolicy
    extends ch.qos.logback.core.rolling.TimeBasedRollingPolicy
{

    public void start ( )
    {
        super.start( );
        rollover( );
    }
}