Subversion Repositories sysadmin_scripts

#! /usr/bin/env perl

use strict;
use warnings;

# Currently three types of tests
# type: lwp
# url: site to test
# timeout: optional integer, number of seconds. defaults to 'default timeout'
#
# type: ping
# url: site to test
# timeout: optional integer, number of seconds. defaults to 'default timeout'
#
# type: netcat
# url: site to test
# port: port to test on
# timeout: optional integer, number of seconds. defaults to 'default timeout'

use Data::Dumper;
use FindBin;
use File::Spec;

# name of script directory, no trailing slash
my $MY_DIR = $FindBin::Bin;
# name of currently executing file
my $MY_NAME = $FindBin::Script;

my $configName = $MY_DIR . '/' . $MY_NAME . '.yaml';

# hashref which holds configuration
my $config;

# simply read the contents of YAML file $filename into
# hashref and return the hashref
sub loadConf {
   use YAML::Tiny;
   my $filename = shift;
   my $conf = YAML::Tiny->read( $filename );
   return $conf->[0];
}

# not used. May use it later, who knows.
sub saveConf {
   use YAML::Tiny;
   my ( $filename, $config ) = @_;
   my $yaml = YAML::Tiny->new( $config );
   $yaml->write( $filename );
}

# check using netcat
sub checkNetCat {
   my ($url, $port, $timeout ) = @_;
   my $netcat = `which nc`;
   chomp $netcat;
   unless ( $netcat ) {
      warn "Netcat not found, not testing\n";
      return 0;
   }
   $netcat = join( ' ', ($netcat, "-z -w $timeout", $url, $port ) );
   `$netcat`;
   return not $? >> 8;
} 

# this has only been tested on http and https, but with a little work
# could do echo, ftp
# will NOT work with some WordPress sites since it goes into
# infinite redirect loop
sub checkHTTP {
   use LWP::UserAgent; # probably should eval this in case not loaded
   my ($url, $timeout) = @_;
   # just getting HEAD, so small amount of data
   my $r = HTTP::Request->new( 'HEAD', $url );
   # new agent, make the request, return success
   my $ua = LWP::UserAgent->new();
   my $res = $ua->request($r);
   return $res->is_success;
}

# we're only using icmp. Probably could extend to other things, but
# netcat and lwp do them also, I think.
# basically a ping. Must be run as root.
sub checkPing {
   my ($url,$type,$timeout) = @_;
   use Net::Ping;
   # verify running as root
   my $login = (getpwuid $>);
   if ( $login ne 'root' ) {
      warn "This script must be run as root for ping type\n";
      return 0;
   }

   my $p = Net::Ping->new('icmp');
   return $p->ping( $url ) ? 1 : 0;
}   

# determines which test to run, runs it and returns results
sub runTest {
   my $parameters = shift;
   #die Dumper( $parameters );
   my $result;
   if ( $parameters->{'type'} eq 'lwp' ) {
      $result = &checkHTTP( $parameters->{'url'}, $parameters->{'timeout'} );
   } elsif ( $parameters->{'type'} eq 'ping' ) {
      $result = checkPing( $parameters->{'url'}, $parameters->{'timeout'} );
   } elsif ( $parameters->{'type'} eq 'netcat' ) {
      $result = checkNetCat( $parameters->{'url'}, $parameters->{'port'}, $parameters->{'timeout'} );
   } else {
      $result = 0;
   }
   return $result;
}

# just make up the flag file name in one place so we don't
# forget to do it everyplace it is needed
sub flagFileName {
   my $name = shift;
   return "/tmp/$name.down";
}

# report the outage
sub reportOutage {
   my ( $name,$parameters ) = @_;
   # do something really nice here
}

# this will put a flag file in /tmp/monitorNetwork which will control
# countdown in case of failure
# if the countdown is exceeded, it will report the status 
sub processFailure {
   my ( $name, $parameters ) = @_;
   # temporary for testing
   print "Failed test for $name\n";
   my $flagFileName = $flagFileName( $name );
   my $remainingCounts = $parameters->{'failure count'};
   if ( -f $flagFileName ) {
      # open flag file, read the value into $remaingCounts
      return if $remainingCounts == -1;
   }
   if ( $remainingCounts-- == 0 ) {
      &ReportOutage( $name, $parameters );
   }
   # open flag file, write new $remainingCounts to it
}

# we are up, so check for any flag file and unlink if found
sub cleanUp {
   my $name = shift;
   $name = &flagFileName( $name );
   unlink $name if -f $name;
}

#######################################################################
#                     Main Code
#######################################################################

# get the config file
$config = &loadConf( $configName );

# loop through each site to check
foreach my $testToRun( keys %{$config->{'sites to check'}} ) {
   # there is a faster way of doing this, but I don't remember it
   # you can merge two hashes, overwriting one with values if not existing in the other
   # I'll look it up, but for now
   foreach my $key ( keys %{$config->{'defaults'}} ) {
      $config->{'sites to check'}->{$testToRun}->{$key} = $config->{'defaults'}->{$key} unless defined $config->{'sites to check'}->{$testToRun}->{$key};
   }
   # run the test
   if ( &runTest( $config->{'sites to check'}->{$testToRun} ) ) {
      &cleanUp( $testToRun ); # success, clean up any old stuff
   } else { # failure, this is what we're here for
      &processFailure( $testToRun, $config->{'sites to check'}->{$testToRun} );
   }
}