neolitec/Catcher.pm

## README.md

      
    Raw
  

              README.md
            
          
    Perl Batch Error Catcher for Nagios

Catcher - Perl extension for error handling
=head1 SYNOPSIS
use Catcher;
#...some piece of code
END_PROGRAM;
Declare errors with custom message

use Catcher;
ERROR "Custom error !";
the program ends here

END_PROGRAM;
Warning handling for Nagios can be disabled for ugly scripts

use Catcher;
warningsOff;
END_PROGRAM;
Warnings can be temporarly disabled

use Catcher;
warningsOff;
ugly instructions

warningsOn;
supposed safe instructions

END_PROGRAM;
For critical scripts, a warning can trigger an error

use Catcher;
dieOnWarn(1);
critical instructions

END_PROGRAM;
Reporting variable can be defined

use Catcher;
use Catcher qw(ReportVars);
reportVar('user_creation', 0);
incVar('user_creation');
incVar('user_creation');
incVar('user_creation');
reportVar('user_modification', 0);
END_PROGRAM;
Reporting variables can be defined in a foreign hash

use Catcher;
use Catcher qw(:ReportVars);
%vars = (
user_creation     => 4,
user_modification => 2
);
setReportVars(%vars);
END_PROGRAM;
Customise the success message

use Catcher;
END_PROGRAM("Custom message");
Customise the success message (other method)

use Catcher;
foo...

setSuccessMessage("foo ok");
bar...

setSuccessMessage("bar ok");
END_PROGRAM;

  
## Catcher.pm
package Catcher;

use strict;
use warnings;
use Carp;
use Carp qw (cluck);
use File::Basename;
use POSIX qw(strftime);

# Nagios error levels
use constant {
	NG_OK       => 0,
	NG_WARNING  => 1,
	NG_CRITICAL => 2,
	NG_UNKNOWN  => 3
};

our (@ISA, @EXPORT, @EXPORT_OK, %EXPORT_TAGS, $NG_REPORT_DIRECTORY);
my ($NG_REPORT_FILENAME);

# Private (internals)
# Recommended settings
my $_SUCCESS = 0;
my $_ERROR = 0;
my $_LEVEL = NG_OK;
my $_DISABLE_WARNINGS = 0;
my $_STOP_ON_WARNING = 0;


# Internal
sub _warn {
	if(!$_DISABLE_WARNINGS) {
		$_ERROR = $_[0];
		$_LEVEL = NG_WARNING;
		$_SUCCESS = 0;
		if($_STOP_ON_WARNING) {
			die $_[0];
		} else {
			warn $_[0];
		}
	}
}

# Exported
sub ERROR {
	$_ERROR = shift;
	$_LEVEL = NG_CRITICAL;
	$_SUCCESS = 0;
	die $_ERROR;
}

BEGIN {
	require Exporter;
	our $VERSION = "1.0.0";
	our @ISA = qw(Exporter);
	# Exported by default
	our @EXPORT = qw(ERROR END_PROGRAM warningsOn warningsOff dieOnWarn setNagiosFilename setSuccessMessage);
	# Can be optionally exported
	our @EXPORT_OK = qw(trace $NG_REPORT_DIRECTORY);
	# Tags
	our %EXPORT_TAGS = (
		ReportVars      => [qw(reportVar incVar setReportVars)]
	);
	# Resulting @EXPORT_OK is @EXPORT_OK = qw(trace $NG_REPORT_DIRECTORY reportVar incVar setReportVars);
	Exporter::export_ok_tags('ReportVars');

	# Guess the default Nagios report filename
	$NG_REPORT_FILENAME = basename($0, '.pl');
	# Destination folder for the .nagios file
	# Can be accessed and modified (for tests) although it is discouraged to it.
	$NG_REPORT_DIRECTORY = "/var/log/apps";

	# Catch DIE signals
	$SIG{__DIE__} = sub { ERROR $_[0] };
	# Catch WARN signals
	$SIG{__WARN__} = sub { _warn $_[0] };
}

# Nagios reporting variables
my %report_vars = ();
my $success_message = "OK Execution normale";

# Exported
# Setter for the nagios report filename
sub setNagiosFilename {
	($NG_REPORT_FILENAME) = shift;
}

# Exported
# A program must finish with this instruction.
sub END_PROGRAM {
	($_) = @_;
	if(defined $_) {
		setSuccessMessage($_);
	}
	if(!$_ERROR && !$_LEVEL) {
		$_SUCCESS = 1;
	}
}

# Exported
# When warnings are enabled, the last warning will be reported (if there is no error).
sub warningsOn {
	$_DISABLE_WARNINGS = 0;
}

# Exported
# When warnings are disabled, the errors of "warn" level are totally ignored, but still printed.
sub warningsOff {
	$_DISABLE_WARNINGS = 1;
}

# Exported
# Trigger die when __WARN__ is encountered.
# It transforms the first warn instruction into a die instruction.
sub dieOnWarn {
	($_STOP_ON_WARNING) = shift;
}

### Variables management
# Variable can be defined in order to be reported in Nagios
# Add a variable
sub reportVar {
	my ($key, $value) = @_;
	$report_vars{$key} = $value;
}

sub getReportVar {
	my ($key) = @_;
	return $report_vars{$key};
}

sub incVar {
	my ($key) = @_;
	$report_vars{$key}++;
}

sub setReportVars {
	%report_vars = @_;
}

sub setSuccessMessage {
	($success_message) = @_;
}

# Exportable
sub trace {
	my (@args) = shift();
	foreach my $line (@args) {
		print "$line\n";
	}
}

# Private
my $sanitizePath = sub {
	($_) = @_;
	# hack for not removing last directory
	$_ = "$_/.";
	# Is the destination directory exist ?
	unless(-e) { croak "Directory $_ does not exist !" }
	return dirname($_);
};
my $writeReport = sub {
    my $dest = &$sanitizePath($NG_REPORT_DIRECTORY)."/".$NG_REPORT_FILENAME.".nagios";
    my $safeError;
    if($_SUCCESS) {
    	$safeError = $success_message;
    } else {
    	$safeError = $_ERROR;
    }
    # Delete special chars
    $safeError =~ s/[\|,]+/\-/g;
    # Keep the first line
    my @safeErrorArray = split("\n", $safeError);
    $safeError = $safeErrorArray[0];
    my $content = (strftime "%F-%T", localtime).",$_LEVEL,$safeError";
    # Construct vars restitution
    my @reportVars = ();
    while (my($k, $v) = each(%report_vars)) {
            push @reportVars, "$k=$v";
    }
    my $reportVarsString = join ' ; ', @reportVars;
    if(length($reportVarsString)) {
            $content .= " | ".$reportVarsString;
    }
    open REPORT, ">".$dest;
    print REPORT $content;
    close REPORT;
};

END {
	&$writeReport();
	if(!$_SUCCESS) {
		if($_LEVEL == NG_WARNING) {
			trace "WARNING : $_ERROR";
		} elsif($_LEVEL == NG_CRITICAL) {
			trace "CRITICAL : $_ERROR";
		} elsif($_LEVEL == NG_UNKNOWN) {
			trace "UNKNOWN : $_ERROR";
		}
		exit(1);
	} else {
		trace "SUCCESS";
		exit(0);
	}
};


1;
__END__
=head1 NAME

Catcher - Perl extension for error handling

=head1 SYNOPSIS

  use Catcher;
  #...some piece of code
  END_PROGRAM;

  # Declare errors with custom message
  use Catcher;
  ERROR "Custom error !";
  # the program ends here
  END_PROGRAM;

  # Warning handling for Nagios can be disabled for ugly scripts
  use Catcher;
  warningsOff;
  END_PROGRAM;

  # Warnings can be temporarly disabled
  use Catcher;
  warningsOff;
  # ugly instructions
  warningsOn;
  # supposed safe instructions
  END_PROGRAM;

  # For critical scripts, a warning can trigger an error
  use Catcher;
  dieOnWarn(1);
  # critical instructions
  END_PROGRAM;

  # Reporting variable can be defined
  use Catcher;
  use Catcher qw(ReportVars);
  reportVar('user_creation', 0);
  incVar('user_creation');
  incVar('user_creation');
  incVar('user_creation');
  reportVar('user_modification', 0);
  END_PROGRAM;

  # Reporting variables can be defined in a foreign hash
  use Catcher;
  use Catcher qw(:ReportVars);
  %vars = (
      user_creation     => 4,
      user_modification => 2
  );
  setReportVars(%vars);
  END_PROGRAM;

  # Customise the success message
  use Catcher;
  END_PROGRAM("Custom message");

  # Customise the success message (other method)
  use Catcher;
  # foo...
  setSuccessMessage("foo ok");
  # bar...
  setSuccessMessage("bar ok");
  END_PROGRAM;
	package Catcher;

	use strict;
	use warnings;
	use Carp;
	use Carp qw (cluck);
	use File::Basename;
	use POSIX qw(strftime);

	# Nagios error levels
	use constant {
	NG_OK => 0,
	NG_WARNING => 1,
	NG_CRITICAL => 2,
	NG_UNKNOWN => 3
	};

	our (@ISA, @EXPORT, @EXPORT_OK, %EXPORT_TAGS, $NG_REPORT_DIRECTORY);
	my ($NG_REPORT_FILENAME);

	# Private (internals)
	# Recommended settings
	my $_SUCCESS = 0;
	my $_ERROR = 0;
	my $_LEVEL = NG_OK;
	my $_DISABLE_WARNINGS = 0;
	my $_STOP_ON_WARNING = 0;


	# Internal
	sub _warn {
	if(!$_DISABLE_WARNINGS) {
	$_ERROR = $_[0];
	$_LEVEL = NG_WARNING;
	$_SUCCESS = 0;
	if($_STOP_ON_WARNING) {
	die $_[0];
	} else {
	warn $_[0];
	}
	}
	}

	# Exported
	sub ERROR {
	$_ERROR = shift;
	$_LEVEL = NG_CRITICAL;
	$_SUCCESS = 0;
	die $_ERROR;
	}

	BEGIN {
	require Exporter;
	our $VERSION = "1.0.0";
	our @ISA = qw(Exporter);
	# Exported by default
	our @EXPORT = qw(ERROR END_PROGRAM warningsOn warningsOff dieOnWarn setNagiosFilename setSuccessMessage);
	# Can be optionally exported
	our @EXPORT_OK = qw(trace $NG_REPORT_DIRECTORY);
	# Tags
	our %EXPORT_TAGS = (
	ReportVars => [qw(reportVar incVar setReportVars)]
	);
	# Resulting @EXPORT_OK is @EXPORT_OK = qw(trace $NG_REPORT_DIRECTORY reportVar incVar setReportVars);
	Exporter::export_ok_tags('ReportVars');

	# Guess the default Nagios report filename
	$NG_REPORT_FILENAME = basename($0, '.pl');
	# Destination folder for the .nagios file
	# Can be accessed and modified (for tests) although it is discouraged to it.
	$NG_REPORT_DIRECTORY = "/var/log/apps";

	# Catch DIE signals
	$SIG{__DIE__} = sub { ERROR $_[0] };
	# Catch WARN signals
	$SIG{__WARN__} = sub { _warn $_[0] };
	}

	# Nagios reporting variables
	my %report_vars = ();
	my $success_message = "OK Execution normale";

	# Exported
	# Setter for the nagios report filename
	sub setNagiosFilename {
	($NG_REPORT_FILENAME) = shift;
	}

	# Exported
	# A program must finish with this instruction.
	sub END_PROGRAM {
	($_) = @_;
	if(defined $_) {
	setSuccessMessage($_);
	}
	if(!$_ERROR && !$_LEVEL) {
	$_SUCCESS = 1;
	}
	}

	# Exported
	# When warnings are enabled, the last warning will be reported (if there is no error).
	sub warningsOn {
	$_DISABLE_WARNINGS = 0;
	}

	# Exported
	# When warnings are disabled, the errors of "warn" level are totally ignored, but still printed.
	sub warningsOff {
	$_DISABLE_WARNINGS = 1;
	}

	# Exported
	# Trigger die when __WARN__ is encountered.
	# It transforms the first warn instruction into a die instruction.
	sub dieOnWarn {
	($_STOP_ON_WARNING) = shift;
	}

	### Variables management
	# Variable can be defined in order to be reported in Nagios
	# Add a variable
	sub reportVar {
	my ($key, $value) = @_;
	$report_vars{$key} = $value;
	}

	sub getReportVar {
	my ($key) = @_;
	return $report_vars{$key};
	}

	sub incVar {
	my ($key) = @_;
	$report_vars{$key}++;
	}

	sub setReportVars {
	%report_vars = @_;
	}

	sub setSuccessMessage {
	($success_message) = @_;
	}

	# Exportable
	sub trace {
	my (@args) = shift();
	foreach my $line (@args) {
	print "$line\n";
	}
	}

	# Private
	my $sanitizePath = sub {
	($_) = @_;
	# hack for not removing last directory
	$_ = "$_/.";
	# Is the destination directory exist ?
	unless(-e) { croak "Directory $_ does not exist !" }
	return dirname($_);
	};
	my $writeReport = sub {
	my $dest = &$sanitizePath($NG_REPORT_DIRECTORY)."/".$NG_REPORT_FILENAME.".nagios";
	my $safeError;
	if($_SUCCESS) {
	$safeError = $success_message;
	} else {
	$safeError = $_ERROR;
	}
	# Delete special chars
	$safeError =~ s/[\\|,]+/\-/g;
	# Keep the first line
	my @safeErrorArray = split("\n", $safeError);
	$safeError = $safeErrorArray[0];
	my $content = (strftime "%F-%T", localtime).",$_LEVEL,$safeError";
	# Construct vars restitution
	my @reportVars = ();
	while (my($k, $v) = each(%report_vars)) {
	push @reportVars, "$k=$v";
	}
	my $reportVarsString = join ' ; ', @reportVars;
	if(length($reportVarsString)) {
	$content .= " \| ".$reportVarsString;
	}
	open REPORT, ">".$dest;
	print REPORT $content;
	close REPORT;
	};

	END {
	&$writeReport();
	if(!$_SUCCESS) {
	if($_LEVEL == NG_WARNING) {
	trace "WARNING : $_ERROR";
	} elsif($_LEVEL == NG_CRITICAL) {
	trace "CRITICAL : $_ERROR";
	} elsif($_LEVEL == NG_UNKNOWN) {
	trace "UNKNOWN : $_ERROR";
	}
	exit(1);
	} else {
	trace "SUCCESS";
	exit(0);
	}
	};



	1;
	__END__
	=head1 NAME

	Catcher - Perl extension for error handling

	=head1 SYNOPSIS

	use Catcher;
	#...some piece of code
	END_PROGRAM;

	# Declare errors with custom message
	use Catcher;
	ERROR "Custom error !";
	# the program ends here
	END_PROGRAM;

	# Warning handling for Nagios can be disabled for ugly scripts
	use Catcher;
	warningsOff;
	END_PROGRAM;

	# Warnings can be temporarly disabled
	use Catcher;
	warningsOff;
	# ugly instructions
	warningsOn;
	# supposed safe instructions
	END_PROGRAM;

	# For critical scripts, a warning can trigger an error
	use Catcher;
	dieOnWarn(1);
	# critical instructions
	END_PROGRAM;

	# Reporting variable can be defined
	use Catcher;
	use Catcher qw(ReportVars);
	reportVar('user_creation', 0);
	incVar('user_creation');
	incVar('user_creation');
	incVar('user_creation');
	reportVar('user_modification', 0);
	END_PROGRAM;

	# Reporting variables can be defined in a foreign hash
	use Catcher;
	use Catcher qw(:ReportVars);
	%vars = (
	user_creation => 4,
	user_modification => 2
	);
	setReportVars(%vars);
	END_PROGRAM;

	# Customise the success message
	use Catcher;
	END_PROGRAM("Custom message");

	# Customise the success message (other method)
	use Catcher;
	# foo...
	setSuccessMessage("foo ok");
	# bar...
	setSuccessMessage("bar ok");
	END_PROGRAM;