Re: [log4perl-devel] Good use of the $logger->log() method

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

On Wed, 4 Jul 2012, Meir Guttman wrote:

> Well, I found at least one use for the $logger->log() method: dynamic level logging.

Hi Meir,

that's an interesting use case, thanks for reporting it. I've changed
the documentation accordingly:

     https://github.com/mschilli/log4perl/commit/b60c85acb482095a5d1939c2a25e64653f3c3624

-- 
-- Mike

Mike Schilli
m...@pe...

> I have though an issue with one passage in the documentation. In the CPAN page Log::Log4perl (Ver. 1.37) (http://search.cpan.org/~mschilli/Log-Log4perl-1.37/lib/Log/Log4perl.pm) one can read the following:
>
>    Instead of calling the methods
>
>        $logger->trace("...");  # Log a trace message
>        ... (other variants deleted)
>
>    you could also call the log() method with the appropriate level using the constants defined in Log::Log4perl::Level:
>
>        use Log::Log4perl::Level;
>
>        $logger->log($TRACE, "...");
>        ... (other variants deleted)
>
>    But *** nobody does that, really ***. (my enhancement - MG) Neither
>    does anyone need more logging levels than these predefined ones. If
>    you think you do, I would suggest you look into steering your logging
>    behavior via the category mechanism.
>
> Well, I found at least one use for the $logger->log() method: dynamic level logging.
>
> Take for example a "system()" call. It can return a number of exit codes by issuing something like «exit(0x2C);» command. I find it very convenient to segregate on the basis of the return code what logging level to assign to the log message upon returning:
>
>    my %exit_level = (
>      0 => $INFO,
>      1 => $WARN,
>      2 => $WARN,
>      4 => $ERROR,
>      0xFF => $FATAL,
>      );
>
>    My %message = (
>      0 => "Message 1",
>      1 => "..."
>      ...
>      );
>
>    my $result = system ('perl', 'my_script.pl, @args) >>= 8;
>
>    $logger->log($exit_level{$result}, $message{$result});
>
> So, I would recommend a change in the doc showing such an example.
>
> Meir
>
>
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