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bin/QueueDaemon.pl  view on Meta::CPAN

########################################################################
package main;
########################################################################

use Class::Inspector;
use Class::Unload;
use Cwd;
use Data::Dumper;
use English qw(-no_match_vars);
use File::Basename qw(fileparse);
use Getopt::Long qw(:config no_ignore_case);
use List::Util qw(max min);
use Log::Log4perl;
use Log::Log4perl::Level;
use Pod::Usage;
use Proc::Daemon;
use Proc::PID::File;
use Module::Load qw(autoload);

use Amazon::SQS::Config;
use Amazon::SQS::Client;

use Readonly;

Readonly::Scalar our $TRUE  => 1;
Readonly::Scalar our $FALSE => 0;

Readonly::Scalar our $DEFAULT_SLEEP_TIME => 5;
Readonly::Scalar our $MAX_SLEEP_TIME     => 60;
Readonly::Scalar our $APPENDER_NAME      => 'LOGFILE';

Readonly::Scalar our $LOGFILE_CONFIG => <<'END_OF_LOGGER';
log4perl.rootLogger=INFO, LOGFILE
log4perl.appender.LOGFILE=Log::Log4perl::Appender::File
log4perl.appender.LOGFILE.filename=%s
log4perl.appender.LOGFILE.mode=append
log4perl.appender.LOGFILE.layout=PatternLayout
log4perl.appender.LOGFILE.layout.ConversionPattern=%%d (%%r,%%R) (%%p/%%c) [%%P] [%%M:%%L] - %%m%%n
END_OF_LOGGER

Readonly::Scalar our $SCREEN_CONFIG => <<'END_OF_LOGGER';
log4perl.rootLogger=INFO, SCREEN
log4perl.appender.SCREEN=Log::Log4perl::Appender::Screen
log4perl.appender.SCREEN.stderr=%s
log4perl.appender.SCREEN.layout=PatternLayout
log4perl.appender.SCREEN.layout.ConversionPattern=%%d (%%r,%%R) (%%p/%%c) [%%P] [%%M:%%L] - %%m%%n
END_OF_LOGGER

our $KEEP_GOING = $TRUE;
our $RELOAD     = $FALSE;

########################################################################
sub get_options {
########################################################################
  my @option_specs = qw(
    config|c=s
    create-queue|C
    daemonize|d!
    delete-when|D=s
    exit-when|E=s
    endpoint_url|e=s
    help|h
    logfile|L=s
    loglevel|l=s
    max-children|m=i
    max-sleep-time=i
    max-messages=i
    pidfile|p=s
    queue|q=s
    queue-interval|I=i
    handler|H=s
    message-type|M=s
    visibility-timeout|v=i
    wait-time|w=i
  );

  # default options
  my %options = (
    daemonize     => $TRUE,
    'exit-when'   => 'never',
    'delete-when' => 'true',                      # delete message if handled successfully
    handler       => 'Amazon::SQS::QueueHandler',
  );

  my $retval = GetOptions( \%options, @option_specs );

  if ( !$retval || $options{help} ) {
    pod2usage(1);
  }

  die "set 'wait-time' or 'queue-interval' but not both\n"
    if $options{'wait-time'} && $options{'queue-interval'};

  return %options;
}

########################################################################
sub main {
########################################################################

  my %options = get_options();

  die sprintf "no such file %s\n", $options{config}
    if $options{config} && ( !-e $options{config} || !-r $options{config} );

  my $config = load_config( \%options );

  if ( !defined $options{'wait-time'} && !defined $options{'queue-interval'} ) {
    $options{'queue-interval'} = $DEFAULT_SLEEP_TIME;
  }

  if ( $options{'queue-interval'} && !defined $options{'max-sleep-time'} ) {
    $options{'max-sleep-time'} = $MAX_SLEEP_TIME;
  }

  my $logger = init_logger( \%options );

  $logger->trace(
    Dumper(
      [ config  => $config,
        options => \%options

bin/QueueDaemon.pl  view on Meta::CPAN

  return;
}

########################################################################
sub load_config {
########################################################################
  my ($options) = @_;

  return
    if !$options->{config};

  my $config = Amazon::SQS::Config->new( file => $options->{config} );

  $options->{loglevel} //= $config->get_log_level;

  $options->{logfile} //= $config->get_log_file;
  $options->{logfile} //= 'stderr';

  $options->{'delete-when'} //= $config->get_error_delete;

  $options->{'exit-when'} //= $config->get_error_exit;

  $options->{handler} //= $config->get_handler_class;

  $options->{'max-sleep-time'} //= $config->get_queue_max_wait;

  $options->{'max-messages'} //= $config->get_queue_max_messages // 1;

  $options->{queue} //= $config->get_queue_name;

  $options->{'queue-url'} //= $config->get_queue_url;

  $options->{'queue-interval'} //= $config->get_queue_interval;

  $options->{'create-queue'} //= $config->get_queue_create_queue // $FALSE;

  $options->{'visibility-timeout'} //= $config->get_queue_visibility_timeout;

  $options->{'wait-time'} //= $config->get_queue_wait_time;

  return $config;
}

########################################################################
sub load_handler {
########################################################################
  my %args = @_;

  my ( $config, $options, $logger, $credentials ) = @args{qw(config options logger credentials)};

  if ( Class::Inspector->loaded( $options->{handler} ) ) {
    Class::Unload->unload( $options->{handler} );
  }

  autoload $options->{handler};

  my $handler = $options->{handler}->new(
    config             => $config,
    logger             => $logger,
    endpoint_url       => $options->{endpoint_url},
    name               => $options->{queue},
    url                => $options->{'queue-url'},
    message_type       => $options->{'message-type'},
    create_queue       => $options->{'create-queue'},
    wait_time          => $options->{'wait-time'},
    visibility_timeout => $options->{'visibility-timeout'},
    credentials        => $credentials,
  );

  die "not an Amazon::SQS::QueueHandler\n"
    if !$handler->isa('Amazon::SQS::QueueHandler');

  return $handler;
}

########################################################################
sub sleep_time {
########################################################################
  my ( $sleep, $options ) = @_;

  $sleep //= 0;

  return $sleep + $options->{'queue-interval'};
}

exit main();

1;

__END__

=pod

=head1 NAME 

QueueDaemon.pl - wrapper for queue handler daemons

=head1 SYNOPSIS

 QueueDaemon.pl options

Read and process SQS messages.

=head1 DESCRIPTION

Implements a daemon that reads from Amazon's Simple Queue Service
(SQS).

=head1 OPTIONS

 -h, --help               help
 -c, --config             config file name
 -C, --create-queue       create the queue if it does not exist
 -d, --daemonize          daemonize the script (default)
     --no-daemonize       
 -D, --delete-when        never, always, error
 -E, --exit-when          never, always, error, false
 -e, --endpoint-url       default: https://sqs.amazonaws.com
 -L, --logfile            name of logfile
 -l, --loglevel           log level (trace, debug, info, warn, error)
 -H, --handler            name of the handler class, default: Amazon::SQS::QueueHandler
 -m, --max-children       not implemented (default: 1)
 -s, --max-sleep-time     default: 5 seconds
     --max-messages       fixed at 1 currently
 -M, --message-type       mime type of messages (text/plain, application/json, 
                          application/x-www-form-encoded), default: text/plain
 -q, --queue              queue name (not url)
     --queue-interval     amount of time to sleep
 -p, --pidfile            fully qualified path of pid file, default: /var/run/QueueDaemon.pl.in
 -v, --visibility-timeout visibility timeout in seconds, default: 30
 -w, --wait-time          long polling wait time in seconds, default: 0

=head2 LICENSE

(c) Copyright 2024 TBC Development Group, LLC. All rights reserved.
This is free software and may be used or distributed under the same terms as Perl itself.

=head1 FEATURES

=over 5

=item * easy configuration using the command line options or a configuration file

=item * automatically create a queue if it doesn't exist

=item * long or short polling. Set --wait-time for long polling, --queue-interval for short polling

=item * configurable message disposition options for successful handling of messages and exceptions

=item * can be run as a daemon or in a terminal

=back

=head1 HINTS & TIPS

=head2 Quick Start

 QueueDaemon.pl --create-queue -q fooManQueue

=over 5 

=item 1. If the queue does not exist it will be created if you use the --create-queue option.

=item 2. If no logfile is given, log output will be sent to STDERR

=item 3. See L<Amazon::SQS::Config> regarding the available options in a config file.

=item 4. The default is to daemonize the script. Use --no-daemonize to run in a terminal.

=item 5. If you do not provide a handler on the command line or in
your .ini file the default handler will be used. The default hanlder will dump the
message to the log and delete the message.

=item 6. By default messages will only be deleted from the queue if your
handler returns a true value. If you want to delete messages which cannot be
decoded or when you handler returns a non-true value, set the
--delete-when or set 'delete' option in the [error] section of your .ini file.