Trac supports logging of system messages using the standard logging module that comes with Python.
Logging is configured in the [logging] section in trac.ini.
The log method is set using the log_type option in trac.ini, which takes any of the following values:
The verbosity level of logged messages can be set using the log_level option in trac.ini. The log level defines the minimum level of urgency required for a message to be logged, and those levels are:
Note that starting with Trac 0.11.5 you can in addition enable logging of SQL statements, at debug level. This is turned off by default, as it's very verbose (set [trac] debug_sql = yes in TracIni to activate).
Starting with Trac 0.10.4 (see #2844), it is possible to set the output format for log entries. This can be done through the log_format option in trac.ini. The format is a string which can contain any of the Python logging Formatter variables. Additonally, the following Trac-specific variables can be used:
Note that variables are identified using a dollar sign ($(...)s) instead of percent sign (%(...)s).
The default format is:
log_format = Trac[$(module)s] $(levelname)s: $(message)s
In a multi-project environment where all logs are sent to the same place (e.g. syslog), it makes sense to add the project name. In this example we use basename since that can generally be used to identify a project:
log_format = Trac[$(basename)s:$(module)s] $(levelname)s: $(message)s
See also: TracIni, TracGuide, TracEnvironment