man Log::Agent::Priorities () - conversion between syslog priorities and levels


Log::Agent::Priorities - conversion between syslog priorities and levels


 Not intended to be used directly


This package contains routines to convert between syslog priorities and logging levels: level_from_prio(crit) yields 2, and prio_from_level(4) yields warning, as does prio_from_level(5).

Here are the known priorities (which may be abbreviated to the first 2 letters, in a case-insensitive manner) and their corresponding logging level:

      Name    Level   Traditional    Export
    --------- -----  --------------  ------
    none       -1                    NONE    (special, see text)
    emergency   0    (emerg, panic)  EMERG
    alert       1                    ALERT
    critical    2    (crit)          CRIT
    error       3    (err)           ERROR
    warning     4                    WARN
    notice      6                    NOTICE
    info        8                    INFO
    debug       10                   DEBUG

The values between parenthesis show the traditional syslog priority tokens. The missing levels (5, 7, 9) are there for possible extension. They currently map to the level immediately below.

The Export column lists the symbolic constants defined by this package. They can be imported selectively, or alltogether via the CW:LEVELS tag, as in:

    use Log::Agent::Priorities qw(:LEVELS);

The special token none may be used (and spelled out fully) on special occasions: it maps to -1, and is convenient when specifying a logging level, for instance: specifying none ensures that no logging will take place, even for emergency situations.

Anywhere where a priority is expected, one may specify a number taken as a logging level or a string taken as a priority. If the default mapping outlined above is not satisfactory, it can be redefined by specifying, for instance CW"notice:9". It will be taken as being of level 9, but with a CWnotice priority nonetheless, not CWinfo as it would have been implicitely determined otherwise.

The routine priority_level() decompiles CW"notice:9" into (notice, 9), and otherwise uses prio_from_level() or level_from_prio() to compute the missing informatin. For instance, given critical, priority_level() routine will return the tuple (critical, 2).


Raphael Manfredi <>