Question

What configuration values are needed to setup Log4j to use the following pattern?
MyApp-Mon.log
MyApp-Tue.log
MyApp-Wed.log
Etc

With each file containing the days log.

This sounds easy enough to do with Log4j’s DailyRollingFileAppender but I am having trouble.
Here is my current config;

<appender name="daily-file" class="org.apache.log4j.DailyRollingFileAppender">
    <param name="Threshold" value="info"/>
    <param name="DatePattern" value="'-'EE'.log'"/>
    <param name="file" value="MyApp"/>
    <param name="Append" value="true" />
    <layout class="org.apache.log4j.PatternLayout">
        <param name="ConversionPattern" value="%d{EEE MMM dd hh:mm:ss zzz yyyy} %-5p %l - %m%n"/>
    </layout>
</appender>

I based this config on this blog post, but it is not behaving in the way he describes. The log is being created as MyApp with no extension.

Can anyone help me out here?

Answer 1

I based this config on this blog post, but it is not behaving in the way he describes. The log is being created as MyApp with no extension.

This is what you told Log4J to do with this line:

<param name="file" value="MyApp"/>

Log4J uses the value of this option as log file name and the pattern is only applied when the roll over occurs, as documented:

For example, if the File option is set
to /foo/bar.log and the DatePattern
set to ‘.’yyyy-MM-dd, on 2001-02-16 at
midnight, the logging file
/foo/bar.log will be copied to
/foo/bar.log.2001-02-16 and logging
for 2001-02-17 will continue in
/foo/bar.log until it rolls over the
next day.

So everything looks normal to me.

To obtain the desired behavior, you could write your own Appender. It looks like James Stauffer did something very similar (see this answer) but he extends FileAppender. It should be easy to adapt his work for a DailyRollingFileAppender subclass though.