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Logging Configuration

Fuse ESB uses the OPS4j Pax Logging system, a standard OSGi logging service that also supports the following APIs:

Three configuration files in the InstallDir/etc directory are used in configuring Fuse ESB logging:

org.ops4j.pax.logging.cfg

Uses standard Log4j configuration to set the root logger's level to INFO and to define two appenders: one for the console and one for the log file. The console's appender is disabled by default. To enable it, add log4j.appender.stdout.append=true to the .cfg file.

org.apache.karaf.log.cfg

Configures the output of the log console commands.

system.properties

Contains one property, org.ops4j.pax.logging.DefaultServiceLog.level, which sets the logging level early in the boot process when the pax-logging service it not yet available. This is set to ERROR by default.

The default logging configuration sets the logging levels so that the log file will provide enough information to monitor the behavior of the runtime and provide clues about what caused a problem. However, the default configuration will not provide enough information to debug most problems.

The most useful logger to change when trying to debug an issue with Fuse ESB is the root logger. You will want to set its logging level to DEBUG in the org.ops4j.pax.logging.cfg file.

Example 4.1. Changing Logging Levels

# Root logger
log4j.rootLogger=DEBUG, out, osgi:VmLogAppender

...

When debugging a problem in Fuse ESB you may want to change the level of logging information that is displayed on the console. Example 4.2 shows an example of setting the root logger to DEBUG but limiting the information displayed on the console to WARN.

Example 4.2. Changing the Log Information Displayed on the Console

log4j.rootLogger=DEBUG, stdout, osgi:VmLogAppender
...

log4j.appender.stdout.threshold=WARN
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%d{ABSOLUTE} | %-5.5p | %-16.16t | %-32.32c{1} | %-32.32C %4L | %m%n

...

It is possible to reconfigure Fuse ESB logging so that it writes one log file for each bundle, instead of writing all of the log messages into a single log file. This feature is enabled by adding the Log4j sift appender to the Log4j root logger. Open the etc/org.ops4j.pax.logging.cfg file using a text editor and add sift to the root logger, as follows:

# Root logger
log4j.rootLogger=INFO, out, sift, osgi:VmLogAppender

After restarting the container, you can see that each BundleName bundle now has its own log file, located at:

data/log/BundleName.log

This is the behavior you will see with the default sift appender settings (see the sift appender configuration settings in org.ops4j.pax.logging.cfg).

For more information on Pax logging, see http://wiki.ops4j.org/display/paxlogging/Pax+Logging.

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