Logback.xml - limit the size of files

Question

I'm trying to figure out if there is a way limit the size of log files within the logback.xml configuration file.

I've reviewed the SDL documentation, which points me to the official documentation (here), which suggests adding the following:

<appender>
...
<maxFileSize>5MB</maxFileSize>
...
</appender>

But after restarting the services, I can see my file has grown more than I've configured. Does anyone have an example of their logback.xml showing a working / restricted files?

Answer 1

[UPDATED]

The following XML is also given on the logback site. This uses the RollingFileAppender and suggests that the 'maxFileSize' element needs to be inside a 'triggeringPolicy':

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

    <rollingPolicy class="ch.qos.logback.core.rolling.FixedWindowRollingPolicy">
      <fileNamePattern>tests.%i.log.zip</fileNamePattern>
      <minIndex>1</minIndex>
      <maxIndex>3</maxIndex>
    </rollingPolicy>

    <triggeringPolicy class="ch.qos.logback.core.rolling.SizeBasedTriggeringPolicy">
      <maxFileSize>5MB</maxFileSize>
    </triggeringPolicy>
    <encoder>
      <pattern>%-4relative [%thread] %-5level %logger{35} - %msg%n</pattern>
    </encoder>
  </appender>

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

The following information is also given on the site too:

Specified number is not in proper int form, or not expected format.

When you specify the MaxFileSize to be used by the SizeBasedTriggeringPolicy, logback expects a rather precise format:

The number has to be an integer You can add 'KB', 'MB' or 'GB' after the number. Here are some correct values: 500KB, 15MB, 2GB.

Answer 2

This works for me:

<appender name="rollingCoreLog" class="ch.qos.logback.core.rolling.RollingFileAppender">
  <rollingPolicy class="ch.qos.logback.core.rolling.TimeBasedRollingPolicy">
    <fileNamePattern>${log.folder}/cd_core.%d{yyyy-MM-dd}.%i.log</fileNamePattern>
    <maxHistory>${log.history}</maxHistory>
    <timeBasedFileNamingAndTriggeringPolicy class="ch.qos.logback.core.rolling.SizeAndTimeBasedFNATP">
      <maxFileSize>1MB</maxFileSize>
    </timeBasedFileNamingAndTriggeringPolicy>
  </rollingPolicy>
  <encoder>
    <pattern>${log.pattern}</pattern>
  </encoder>
  <prudent>true</prudent>
</appender>

I think inserting the node timeBasedFileNamingAndTriggeringPolicy inside the rollingPolicy and using the %i as the index of the numbered files.

If you only want to use a Size triggering, then the previous solution of Jonathan works only if the rolling Policy is "FixedWindowRollingPolicy", not the TimeBasedRollingPolicy used by the logbacks of Tridion examples.