[logback-user] logback and manual rollover (from java)

[Ceki Gülcü]

When you are sure that the underlying framework is logback, you can cast 
an org.slf4j.Logger instance into ch.qos.logback.classic.Logger. The 
latter has a method to retrieve an appender by name [1].

I hope this helps,

[1] 
http://logback.qos.ch/apidocs/ch/qos/logback/classic/Logger.html#getAppender%28java.lang.String%29

On 23/07/2010 10:29 AM, lgonggr wrote:
>
> Hi,
>
> I used log4j before and I triggered my RollingFileAppender rollover()
> manually in some places (batches). I need to create seperate logfiles for
> each batch run.
> I want it to rollover using the FixedWindowRollingPolicy if the logfile
> exceeds 10MB and at the start of each batch run.
> I've migrated to logback now and it works well, but I can't figure out how
> to rollover my RollingFileAppender manually.
>
> What I have now :
>    <appender name="EntityToCSV"
> class="ch.qos.logback.core.rolling.RollingFileAppender">
>       <File>/home/tomcat/overname_test_logs/EntityToCSV.log</File>
>      <encoder>
>        <pattern>%d{yyyy-MM-dd HH:mm:ss} %-5p [%t] %c{1}: %m%n</pattern>
>      </encoder>
>      <rollingPolicy
> class="ch.qos.logback.core.rolling.FixedWindowRollingPolicy">
>        <maxIndex>9</maxIndex>
>
> <FileNamePattern>/home/tomcat/overname_test_logs/EntityToCSV.log.%i</FileNamePattern>
>      </rollingPolicy>
>      <triggeringPolicy
> class="ch.qos.logback.core.rolling.SizeBasedTriggeringPolicy">
>        <MaxFileSize>10MB</MaxFileSize>
>      </triggeringPolicy>
>    </appender>
>
>    <logger name="nl.realworks.apps.overname.EntityToCSV" level="INFO">
>      <appender-ref ref="EntityToCSV"/>
>    </logger>
>
> in EntityToCSV.java :
>
> 	private static final Logger LOGGER =
> 		LoggerFactory.getLogger(EntityToCSV.class);
>
>         public static void main(String[] args) throws Exception {
> 		
> 		OvernameUtils.manualRollover(LOGGER);
>
>                   // do stuff and log it
>
> in OvernameUtils.java :
>
> 	public static void manualRollover(Logger logger) {
> 		Utils.assertNotNull("logger is null.", logger);
> 		if (logger instanceof RollingFileAppender) { //<--- FAIL !
> 			try {
> 				((RollingFileAppender)logger).rollover();
> 			} catch (Exception e) {
> 				logger.error("rollover failed.", e);
> 			}
> 			return;
> 		}
> 		String message = logger.getName() +
> 			" is not an instance of RollingFileAppender.";
> 		logger.error(message, new RuntimeException(message));
> 	}
>
> This won't work of course as Logger != Appender. I have no idea how to get
> from the Logger to its Appender(s). In log4j you could just do getAppender()
> but this is not possible with org.slf4j.Logger
>
> Perhaps this is a totally wrong approach. Any tips would be greatly
> appreciated.
>