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[p5sagit/Log-Contextual.git] / lib / Log / Contextual / SimpleLogger.pm

package Log::Contextual::SimpleLogger;

# ABSTRACT: Super simple logger made for playing with Log::Contextual


use strict;
use warnings;

{
   for my $name (qw( trace debug info warn error fatal )) {

      no strict 'refs';

      *{$name} = sub {
         my $self = shift;

         $self->_log($name, @_)
           if ($self->{$name});
      };

      *{"is_$name"} = sub {
         my $self = shift;
         return $self->{$name};
      };
   }
}

sub new {
   my ($class, $args) = @_;
   my $self = bless {}, $class;

   $self->{$_} = 1 for @{$args->{levels}};
   $self->{coderef} = $args->{coderef} || sub { print STDERR @_ };

   if (my $upto = $args->{levels_upto}) {

      my @levels = (qw( trace debug info warn error fatal ));
      my $i      = 0;
      for (@levels) {
         last if $upto eq $_;
         $i++
      }
      for ($i .. $#levels) {
         $self->{$levels[$_]} = 1
      }

   }
   return $self;
}

sub _log {
   my $self    = shift;
   my $level   = shift;
   my $message = join("\n", @_);
   $message .= "\n" unless $message =~ /\n$/;
   $self->{coderef}->(sprintf("[%s] %s", $level, $message));
}

1;

__END__

=head1 SYNOPSIS

 use Log::Contextual::SimpleLogger;
 use Log::Contextual qw( :log ),
   -logger => Log::Contextual::SimpleLogger->new({ levels => [qw( debug )]});

 log_info { 'program started' }; # no-op because info is not in levels
 sub foo {
   log_debug { 'entered foo' };
   ...
 }

=head1 DESCRIPTION

This module is a simple logger made mostly for demonstration and initial
experimentation with L<Log::Contextual>.  We recommend you use a real logger
instead.  For something more serious but not overly complicated, take a look at
L<Log::Dispatchouli>.

=head1 METHODS

=head2 new

Arguments: C<< Dict[
  levels      => Optional[ArrayRef[Str]],
  levels_upto => Level,
  coderef     => Optional[CodeRef],
] $conf >>

 my $l = Log::Contextual::SimpleLogger->new({
   levels  => [qw( info warn )],
   coderef => sub { print @_ }, # the default prints to STDERR
 });

or

 my $l = Log::Contextual::SimpleLogger->new({
   levels_upto => 'debug',
   coderef     => sub { print @_ }, # the default prints to STDERR
 });

Creates a new SimpleLogger object with the passed levels enabled and optionally
a C<CodeRef> may be passed to modify how the logs are output/stored.

C<levels_upto> enables all the levels upto and including the level passed.

Levels may contain:

 trace
 debug
 info
 warn
 error
 fatal

=head2 $level

Arguments: C<@anything>

All of the following six methods work the same.  The basic pattern is:

 sub $level {
   my $self = shift;

   print STDERR "[$level] " . join qq{\n}, @_;
      if $self->is_$level;
 }

=head3 trace

 $l->trace( 'entered method foo with args ' join q{,}, @args );

=head3 debug

 $l->debug( 'entered method foo' );

=head3 info

 $l->info( 'started process foo' );

=head3 warn

 $l->warn( 'possible misconfiguration at line 10' );

=head3 error

 $l->error( 'non-numeric user input!' );

=head3 fatal

 $l->fatal( '1 is never equal to 0!' );

=head2 is_$level

All of the following six functions just return true if their respective
level is enabled.

=head3 is_trace

 say 'tracing' if $l->is_trace;

=head3 is_debug

 say 'debuging' if $l->is_debug;

=head3 is_info

 say q{info'ing} if $l->is_info;

=head3 is_warn

 say 'warning' if $l->is_warn;

=head3 is_error

 say 'erroring' if $l->is_error;

=head3 is_fatal

 say q{fatal'ing} if $l->is_fatal;

=cut