4.3. Logging system
Karaf provides a powerful logging system based on OPS4j Pax Logging.
In addition to being a standard OSGi Log service, it supports the following APIs:
- Apache Commons Logging
- SLF4J
- Apache Log4j
- Java Util Logging
Karaf also comes with a set of console commands that can be used to display, view and change the log levels.
Configuration
The configuration of the logging system uses a standard Log4j configuration file at the following location:
[karaf]/etc/org.ops4j.pax.logging.cfg
You can edit this file at runtime and any change will be reloaded and be effective immediately.
Commands
The log subshell comes with 3 commands:
- log:display: display the last log entries
- log:display-exception: display the last exception from the log
- log:get: show the log levels
- log:set: set the log levels
For example, if you want to debug something, you might want to run the following commands:
> log:set DEBUG
... do something ...
> log:display
Note that the log levels set using the log:set commands are not persistent and will be lost upon restart.
To configure those in a persistent way, you should edit the configuration file mentioned above.
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