Monday, April 29, 2013

logcheck – scans your logfiles and warns you

Dependencies and restrictions:
  • logcheck depends on logtail
  • logtail runs on exactly one file …
  • … and only once on that file, as it keeps a sister file called logfile.offset
  • improving this should actually be "easy", e.g. keeping a sister file called logfile.offset.user

  • abstracting resp. filtering log files like /var/log/messages
  • this happens "realtime" i.e. instantly
  • the results get to you resp. a whole crowd via e-mail – isn't that a little excessive regarding the resources necessary to look at the output?
  • if you already have a utilty in place, that filters daily chunks of log files, this is 
Ideas / inspirations taken from here:
  • the output could actually go to another log file, that you may want to "logtail" or "tail -f" as to your needs

Wednesday, April 10, 2013

Log::Log4perl and (supposed) performance penalties

Log::Log4perl - Log4j implementation for Perl -

Evaluating parameters to logger methods may be expensive, but that's outside the scope and responsibility of Log::Log4perl. So if you know that you have "expensive parameters", you may "guard" your logger calls with "...->is_...()" method calls. Otherwise just don't do so! It does not make sense. Read up the above manual page section! Why should the is_trace call be cheaper than the trace call itself? Of course it's not. I guess, you got that.

Tuesday, April 9, 2013

Test::Builder - Backend for building test libraries -

Test::Builder - Backend for building test libraries -

Test::Simple and Test::More have proven to be popular testing modules, but they're not always flexible enough. Test::Builder provides a building block upon which to write your own test libraries which can work together.

TAP::Harness - Run test scripts with statistics -

TAP::Harness - Run test scripts with statistics -

Log::Log4perl - Log4j implementation for Perl -

linked from

its ancestor log4j:
  • "Short introduction to log4j" by Ceki Gülcü, March 2002 [the proper link]
  • log4j's wikipedia [link] with a nice and terse description
  • Vipan Singla's article "Don't Use System.out.println! Use Log4j" [link]

Log::Log4perl lets you remote-control and fine-tune the logging behaviour of your system from the outside. It implements the widely popular (Java-based) Log4j logging package in pure Perl.

Log4perl is also compatible with log4j's graphical log analyser Chainsaw.

Chainsaw (log file viewer) – the log4j and also Log4perl graphical log analyser

Yes, it is compatible with Log::Log4perl, cf. "Can I use Log::Log4perl with log4j's graphical Log Analyzer Chainsaw?" [link] in Log::Log4perl::FAQ.

Monday, April 8, 2013