Alive - crontab service health checker

alive.pl

#!/usr/bin/perl 
#
# alive - crontab service health checker
# Rootnode http://rootnode.net
#
# Copyright (C) 2012 Marcin Hlybin
# All rights reserved.

use warnings;
use strict;
use Proc::ProcessTable;
use Getopt::Long;
use File::Basename;
use IO::Socket;
use Readonly;
use Smart::Comments;

Readonly my $USER => $ENV{USER};
Readonly my $BASENAME => basename($0);
Readonly my $USAGE => <<EOF;
Usage: $BASENAME [ -v|--verbose ] [ --tcp host:port ] [ --sock file_name ] [ --ps process_name | --ps fname,cmndline ]

\033[1mOPTIONS\033[0m
   --tcp host:port       check TCP connection
   --sock file_name      check UNIX socket
   --ps process_name     check process 
   --ps fname,cmndline   check process (detailed)
   --verbose|-v          show status on stdout

Options could be specified multiple times.

List processes with
ps -eo pid,user,fname,command

\033[1mExample usage\033[0m
alive --tcp 127.0.0.1:3306 && echo 'OK' || echo 'NOT OK' 
alive --ps nginx || nginx restart

\033[1mSample crontab entries\033[0m
* * * * *      alive --ps unicorn_rails --sock /home/$USER/unicorn/application1.sock || /home/$USER/bin/start-unicorn.sh
*/15 * * * *   alive --ps sample_server || bash ~/bin/sample_server.sh && (ps wuax | mail -s "Server restarted" $USER\@example.com)
* * * * *      alive --ps nginx --tcp 10.1.12.34:8080 || nginx restart

\033[1mUsage inside the script\033[0m
if alive --ps nginx 
then
	do_some_action_here()
fi

EOF

GetOptions(\my %opt,
	'ps=s@',        # process name or fname, cmndline
	'sock|tcp=s@',  # host:port or file name
	'verbose',      # show status code
	'help',         # show help
);

my %result;
$result{ps}   = ps($opt{ps})     if defined $opt{ps};
$result{sock} = sock($opt{sock}) if defined $opt{sock};

die $USAGE unless keys %result;

my @fail = grep defined, values %result;
my $status_code = scalar @fail;

if ($opt{verbose}) {
	my $status_message = $status_code ? 'FAILED: ' . join (', ', @fail) : 'OK';
	print "$status_message\n";
}

exit $status_code;

sub ps {
	# Process name check
	my ($process_ref) = @_;

	# Get process list
	my $proc = new Proc::ProcessTable;
	
	PROCESS:
	foreach my $process_name (@$process_ref) {
		# Split file name and command name 
		# if process name defined with comma
		my ($fname, $cmndline) = split /,/, $process_name;
		
		PS:
		foreach my $p ( @{$proc->table} ) {
		  # Match file name and command name separately 
			if (defined ($fname and $cmndline)) {
				if ($p->fname eq $fname and
				    $p->cmndline =~ /^$cmndline/) {
					next PROCESS;
				}
			}
			# Try to match file name or command name
			else {
				if ($p->fname    eq $fname or
				    $p->cmndline eq $fname) {
					next PROCESS;
				}
			}
		}

		return $process_name;
	}

	return;
}

sub sock {
	# Check connection to the socket
	my ($socket_ref) = @_;

	SOCKET:
	foreach my $socket_name (@$socket_ref) {
		# Split socket name into host and port 
		my ($host, $port) = split /:/, $socket_name;
	
		# Choose socket type
		my $socket_type = defined ($host and $port) ? 'INET' : 'UNIX';

		# Connect to socket
		my $IO = "IO::Socket::$socket_type";
		my $socket = $IO->new($socket_name);
		if ($socket) {
			$socket->close;
			next SOCKET;
		}

		return $socket_name;
	}

	return;
}

Usage

Usage: alive [ -v|--verbose ] [ --tcp host:port ] [ --sock file_name ] [ --ps process_name | --ps fname,cmndline ]

OPTIONS
   --tcp host:port       check TCP connection
   --sock file_name      check UNIX socket
   --ps process_name     check process
   --ps fname,cmndline   check process (detailed)
   --verbose|-v          show status on stdout

Options could be specified multiple times.

List processes with
ps -eo pid,user,fname,command

Example usage
alive --tcp 127.0.0.1:3306 && echo 'OK' || echo 'NOT OK'
alive --ps nginx || nginx restart

Sample crontab entries
* * * * *      alive --ps unicorn_rails --sock /home/marcin/unicorn/application1.sock || /home/marcin/bin/start-unicorn.sh
*/15 * * * *   alive --ps sample_server || bash ~/bin/sample_server.sh && (ps wuax | mail -s "Server restarted" marcin@example.com)
* * * * *      alive --ps nginx --tcp 10.1.12.34:8080 || nginx restart

Usage inside the script
if alive --ps nginx
then
	do_some_action_here()
fi