I just released Log::Sprintf and Log::Structured to CPAN. They are both very simple modules, but they allow some powerful stuff.

Log::Sprintf will convert a hashref into a string given a specification almost conformant to Log::log4perl’s log specs. The example from the SYNOPSIS is as follows:

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 my $log_formatter = Log::Sprintf->new({
   category => 'DeployMethod',
   format   => '[%L][%p][%c] %m',
 });

 $log_formatter->sprintf({
   line     => 123,
   package  => 'foo',
   priority => 'trace',
   message  => 'starting connect',
 });

Also it was made with subclassing in mind from the start, so it is easy to add more flags as needed.

Log::Structured is a more generic tool but arguably more powerful. All it does is generate a “simple” (easily serializable) data structure and call a coderef that you give it with the data structure. What I hope to do with that is log to standard error using Log::Sprintf, but then log to a file using newline separated JSON documents. That means I can parse the log file DEAD easily and do what I want with it. Here’s the SYNOPSIS (after Log::Sprintf-ification) for that:

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 use Log::Structured;
 use Log::Sprintf;

 my $formatter = Log::Sprintf->new({ format => "[%d][%F:%L][%p][%c] %m" });

 my $structured_log = Log::Structured->new({
   category            => 'Web Server',
   log_category        => 1,
   priority            => 'trace',
   log_priority        => 1,
   log_file            => 1,
   log_line            => 1,
   log_date            => 1,
   log_event_listeners => [sub {
      warn $formatter->sprintf($_[1])
   }, sub {
      open my $fh, '>>', 'log';
      print {$fh} encode_json($_[1]) . "\n";
   }],
 });

 $structured_log->log_event({ message => 'Starting web server' });

 $structured_log->log_event({
   message => 'Oh no!  The database melted!',
   priority => 'fatal',
   category => 'Core',
 });

Anyway, hope you find a handy use for these!