lwes-perl-journal-listener

#!/usr/bin/env perl

use strict;
use warnings;

use Getopt::Long;
use Pod::Usage;
use LWES::EventParser;
use LWES::Listener;
use POSIX qw(strftime);

my $help_opt         = 0;
my $man_opt          = 0;
my $verbose_opt      = 0;
my $stats_opt        = 0;

Getopt::Long::Configure ("pass_through");

GetOptions
  (
    'help'           => \$help_opt,
    'man'            => \$man_opt,
    'stats'          => \$stats_opt,
    'verbose'        => \$verbose_opt,
  ) or pod2usage (2);

pod2usage (-exitval => -1, -verbose => 0) if $help_opt;
pod2usage (-exitval => -2, -verbose => 2) if $man_opt;

my $listener_or_code;

# if the first argument is a file, we'll assume it s a journal file, and
# use the PrintingListener
if (-f $ARGV[0])
  {
    $listener_or_code = "LWES::Listeners::EventPrintingListener";
  }
else
  {
    $listener_or_code = shift @ARGV;
  }

# determine the callback which will process each event
my $processEventFunc = getProcessEventFunc ($listener_or_code, \@ARGV);

foreach my $journal (@ARGV)
  {
    my $start       = time();
    my $num_events  = 0;
    my $num_success = 0;
    my $num_error   = 0;


    if (-f $journal)
      {
        open FH, "zcat $journal |";

        # read and parse header
        my $header_bytes;
        while ( read (FH, $header_bytes, 22) == 22)
          {
            my $header = bytesToHeader ($header_bytes);

            # read and parse bytes
            my $event_bytes;
            my $n = read (FH, $event_bytes, $header->{'PayloadLength'});
            if (defined ($n) && $n == $header->{'PayloadLength'})
              {
                my $event = bytesToEvent ($event_bytes);

                # merge header into event
                foreach my $h (keys %{$header})
                  {
                    unless (exists ($event->{$h}))
                      {
                        $event->{$h} = $header->{$h};
                      }
                  }

                # call handler
                my ($success, $errors) = $processEventFunc->($event);
                $num_events++;
                if (defined ($success))
                  {
                    $num_success += $success;
                  }
                if (defined ($errors))
                  {
                    $num_error   += $errors;
                  }
              }
            else
              {
                die "malformed or truncated journal";
              }
          }

        close FH;
      }

    if ($stats_opt)
      {
        my $log_date   = strftime ("%a %b %e %H:%M:%S %Y", localtime (time()));
        my $end = time()-$start;
        print "$log_date : $journal had $num_events events processed with $num_success successful actions and $num_error errors in $end seconds\n";
      }
  }

0;

__END__

=head1 NAME

lwes-perl-journal-listener - listens for events from a journal

=head1 SYNOPSIS

lwes-perl-journal-listener [options] [<listener> [<args>] | <code>] <journal(s)>

Options:
  --stats                     Print information about each file processed
  -help                       Brief help message
  -man                        Full Documentation

<listener> is the name of a perl module which extends the base
listener LWES::Listener and provides an initialize and processEvent
method.  The <args> are passed directly to the listener constructor.

code is perl code which is embedded in a function which takes one
argument, a reference to a perl hash which contains the contents
of the event called $event

=head1 OPTIONS

=over 8

=item B<--stats>

Print information about how many events were processed and how long it took
to process.

=item B<-help>

Print help information

=item B<-man>

Print more verbose help information

=back

=head1 DESCRIPTION

The lwes-perl-journal-listener is a tool for inspecting LWES events that
are in journal files created by the lwes-journaller.

There are several ways to use the tool.  To just print out events as they
are seen it can be invoked as

% lwes-perl-journal-listener <journal>

Alternatively you can provide a LWES::Listener module as outlined in
the lwes-perl-event-listener man page.

=cut