Log configuration via log4j
Most log files can be configured using the Java logging framework log4j 1.2 (exceptions are noted
above). Using the log4 configuration you can configure when a new log file is generated, how many log
files to retain, and the log level that shall be used.
The logging configuration is specified via XML based configuration files. XML files depend on their syntax
being intact, which makes them potentially fragile. To allow an easy recovery in the case of XML syntax
errors, backup copies of the log configuration files are provided. The locations of the individual
configuration files and their backup files are listed in the log file specific sections above.
Log files are generated and retained by date up to the configured number of backups. A maximum file
size serves as a safeguard against excessive use of disk space.
The log configuration file declares one or more loggers (as input into the logging system) and one or
more appenders (as output out of the logging system).
Loggers define what will be logged and which log level shall be used. The main logger is called
<root>. It contains the log level to be used for all log output. The log level of individual
components can optionally be set to a different level using additional <logger> sections in the
Appenders define where the log output will be written to (typically a logfile) as well as the timestamp
format and log file rotation specific settings. We typically control activation and deactivation of specific
log files within the appender configuration.
Parameters for both server and client logs
Logging occurs for the levels TRACE, DEBUG, INFO, WARN, ERROR, and FATAL. Each level includes
all log output of the levels listed to its right, e.g. log level WARN includes all log output of levels WARN,
ERROR, and FATAL.
By default, the logging level used is INFO. You can change the logging level using the root logger’s level
parameter. For example:
Individual log levels for specific loggers
In a troubleshooting situation, the ilink support team may request to set individual log levels for specific
loggers. To do so, additional <logger> sections need to be added to the configuration file:
<logger name="...a name...">
The log4j configuration file already contains the above lines as a template, but ilink will send you specific
instructions in such a case, including the name of the logger that should be used.