Version 22 of log

Documentation can be found at http://tcllib.sourceforge.net/doc/log.html .

A side-by-side comparision to the very similar logger package in tcllib can be found here [L1 ].

Also take a look at the audit package at: [L2 ]

LV writes: What are some tips for using this package? For instance, can someone provide a skeleton for using logs to a program. One using has several types of msgs in a program:

introductory (Hi, this is program ABC, and I am here to help you learn to tie your shoes)
progress (program ABC is now loading a 256 terabyte database about types of shoes ... loading ... loading ...)
success/results (program ABC has located your language environment)
failure (program ABC is unable to identify shoes called 'sandels')
completion (Well, thanks for stopping by to talk to me - y'all come back now, ya' hear?)

How would one code a skeleton for such an application (don't worry about the tcl to do the above actual coding - just the logs)?

[Good question(s), Larry.]

PT writes: OK Seeing as I used this in TclSOAP and tkchat...:

 package require log;  # tcllib 1.0

 namespace eval mine {
    variable logLevel warning;  # set up the default level
 }

 # -------------------------------------------------------------------------
 # Description:
 #  Set the amount of logging you would like to see.  We use the tcllib log package for this so the level
 #  must be one of log::levels. The default is 'warning'.
 # Parameters:
 #  level - one of log::levels. See the tcllib log package documentation.
 #
 proc mine::setLogLevel {level} {
     variable logLevel
     set logLevel $level
     log::lvSuppressLE emergency 0; # unsuppress all
     log::lvSuppressLE $logLevel 1; # suppress all below selected
     log::lvSuppress $logLevel 0;   # unsupress selected.
     return $logLevel
 }
 # initialize the default package logging level
 if {[info exists mine::logLevel]} {
     mine::setLogLevel $mine::logLevel
 }

Add a -loglevel configuration option that calls to setLogLevel and then liberally splinkle your code with log::log debug "message" and so forth. So:

 proc mine::DoStuff {args} {
    log::log debug "starting to do stuff"
    if {! [doing stuff]} {
        log::log notice "we are not doing anything!"
    }
    set r [do more stuff]
    if {$r < 1} {
        log::log emergency "argh!"
    }
    log::log debug "stopping doing stuff"
  }

With this pseudo-procedure if the user has set their log level to debug then they will see all these messages printed out.

Raising the log level to notice will reduce the noise but keep the more significant messages. emergency is (IIRC) the higest level.

emergency
alert
critical
error
warning
notice <--- logLevel variable
info........x
debug.......x

The tkchat program uses log levels to provide debugging information for people having trouble and less information for those for whom it works. This program is probably a reasonable example of the use of this package. In this program we use debug and info for http status messages. The output appears at debug level and just the status at info level. Level error is used for reporting failures like timeouts and http protocol errors.

log is also an expr built-in function, "natural" logarithm to base e:

 % expr log(2.71828182846)
 1.0

log is also one of TclX Commands

Category Debugging | Category Package, subset Tcllib