log4perl-devel

[log4perl-devel] Additional logging methodology

[Aldrich, T. <tim...@cs...>]

All,
	I have a large perl project that uses Log::log4perl to log 
everything to a text file.  If the program successfully completes
then this log file is deleted before the program terminates.  It is
invaluable to be able to crank up the category to DEBUG and watch
the file grow :)
	Now I would like to add logging to a different file that get's
appended to during the day.  This new rolling log needs different
information.  It should be general status messages . i.e. program
started , ended , by whom.  My question is , what is the best way to
implement this additional log ?
 I could :
* Pollute my program with print statements (shudder)
* Add a new Log::log4perl category.
* add a Log::log4perl filter

	I'm leaning towards categories because 
$logger->status("I started");
seems to be an easy fix , however the POD discourages the use of a new 
category.  Implementing a filter means I now have to include some type
of destination info in my log messages , and I don't want to revisit
all of my calls to the logger to add destination info !

Any help / insight / advice would be greatly appreciated

	

R/S____________
Timothy Aldrich

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Re: [log4perl-devel] Additional logging methodology

[Mike S. <m...@pe...>]

Aldrich, Timothy wrote on 9/14/2004, 8:20 AM:

 > ow I would like to add logging to a different file that get's
 > appended to during the day.  This new rolling log needs different
 > information.  It should be general status messages . i.e. program
 > started , ended , by whom.  My question is , what is the best way to
 > implement this additional log ?

My first thought is to write out these status messages at a higher 
priority (e.g. INFO), than the DEBUG messages. Typically, DEBUG messages 
provide low-level information about the program flow, while INFO 
messages carry exactly what you have in mind, things like when the 
program started, ended, by whom, major events, etc.

If that's an option for you, leave the categories untouched (changing 
them is a bad idea, they determine where a message came from, not where 
it's going to) and just use

     $logger->info("Program started");

and

     $logger->debug("Some lowlevel info");

Then, use

     http://log4perl.sourceforge.net/d/Log/Log4perl/FAQ.html#c7fa8

to channel them into different log files.

--
-- Mike
Mike Schilli
m...@pe...

Re: [log4perl-devel] Additional logging methodology

[Mike S. <m...@pe...>]

Aldrich, Timothy wrote on 9/14/2004, 8:20 AM:

 > Now I would like to add logging to a different file that get's
 > appended to during the day.  This new rolling log needs different
 > information.  It should be general status messages . i.e. program
 > started , ended , by whom.  My question is , what is the best way to
 > implement this additional log ?
 > I could :
 > * Pollute my program with print statements (shudder)

Shudder, indeed :).

 > * Add a new Log::log4perl category.

Categories determine where a message came from within the system, not 
where it's going to, so I'd recommend leaving them untouched for what 
you're trying to accomplish.

 > * add a Log::log4perl filter

If you want different kinds of messages to go to different output sinks, 
log levels are the recommended way.

In your case, you could log the debug messages like

     $logger->debug("a lowlevel message");

and important events, like when the program started, stopped, etc., via

     $logger->info("Program started");

Then, use

     http://log4perl.sourceforge.net/d/Log/Log4perl/FAQ.html#c7fa8

to channel messages of different priorities to different log files.

--
-- Mike
Mike Schilli
m...@pe...