Time based triggering policy in log4j2

Log4j documentations:

interval -> (integer) How often a rollover should occur based on the most specific time unit in the date pattern. For example, with a date pattern with hours as the most specific item and and increment of 4 rollovers would occur every 4 hours. The default value is 1.

You should change the filename pattern if you would like to create it every hour.


1 here indicates 1 day and not 1 hour. I have manually tested with below configuration.

<RollingFile name="T" fileName="/data_test/log/abc.log"
        filePattern="/data_test/log/abc-%d{MM-dd-yyyy}-%i.log">
        <PatternLayout>
            <Pattern>%d{ISO8601} %-5p [%t] (%F:%L) - %m%n</Pattern>
        </PatternLayout>
        <Policies>              
            <TimeBasedTriggeringPolicy interval="1" modulate="true"/>
            <SizeBasedTriggeringPolicy size="100 KB" />
        </Policies>
    </RollingFile>

For manual testing, I change the system date and time. First, try with increasing 1 hour. The log files will be generated but not as per the expectation. Then change the system date, increase by 1 day and then see the results.

Suppose the last log file (abc.log) on day 29-Oct is of 50 KB. Configuration size is 100 KB. If we change the day (increase by 1 day) and then run. Then, last file will be renamed 29-Oct-(some sequence number).log (50 KB file as it is copied) and new file will be created with abc.log

I have tried this with simple servlet with below configuration in web.xml

<context-param>
    <param-name>log4jConfiguration</param-name>
    <param-value>log4j2.xml</param-value>
</context-param>

keep log4j2.xml in src folder. log4j2.xml is not loaded if we keep it in classpath.