Log::Log4perl and (supposed) performance penalties

Log::Log4perl - Log4j implementation for Perl - metacpan.org

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.

Log::Log4perl - Log4j implementation for Perl - metacpan.org

• log4perl.com
• Log::Log4perl - Log4j implementation for Perl - metacpan.org
• Log::Log4perl::Config - Log4perl configuration file syntax - metacpan.org – everything about the configuration file syntax, includes a "cookbook"
• the initial article on Log::Log4perl at perl.com [link], and the errata [link]
• Michael Schilli at github and esp. his Log4perl [link]
• its nice logo [link at cafepress.com, link at cafepress.de] on a mug or a t-shirt

linked from http://www.cafepress.com/log4perl

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

• Chainsaw (log file viewer) - Wikipedia, the free encyclopedia
• Apache Logging Services Chainsaw v2 Home [link]

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.

logging: Write Logs for Machines, use JSON

Write Logs for Machines, use JSON | Paul's Journal

Looks like a nice new challenge to use JSON also for debug / trace output.

I always found unstructured debug / trace output awful, and of course mine has been "key-value" for a long time.
I learned that "at home", the Karlsruhe Ada Compiler construction team, back in the 80-s.

• Graylog Extended Log Format
• ruby, github: https://github.com/Graylog2/gelf-rb
• perl, METACPAN: Log::Log4perl::Layout::GELF
• perl, github: log4perl_gelf