Monitor page load with PhantomJS, Nagios and Ruby

Used PhantomJS Nagios plugin on CentOS machine with Nagios installed.

1. Install prerequisites:

   yum install glibc fontconfig freetype freetype-devel fontconfig-devel wget bzip2

2. Download, unpack and install PhantomJS:

   wget https://bitbucket.org/ariya/phantomjs/downloads/phantomjs-2.1.1-linux-x86_64.tar.bz2
   tar xvjf phantomjs-2.1.1-linux-x86_64.tar.bz2 -C /usr/local/share/
   ln -sf /usr/local/share/phantomjs-2.1.1-linux-x86_64/bin/phantomjs /usr/local/bin
   phantomjs –version

3. Install Ruby and prerequisites:

   yum install ruby ruby-devel gcc
   gem install json

4. Install nagios plugin (usually it could be placed in nagios plugins directory):

   mkdir page-load-test
   cd page-load-test/
   git clone https://github.com/hggh/phantomjs-nagios.git
   cp check_http_load_time.rb /usr/local/nagios/libexec/

5. Test page load speed:

   ./check_http_load_time.rb --perf -c 60 -w 30 -u http://www.pctags.com -p /usr/local/bin/phantomjs --perf

6. The output should be like this one:

   OK: http://www.pctags.com load time: 0.56 | load_time=556.0ms size=4882 requests=4 dom_elements=23 load_time_initial_req=384ms

7. Setup command in nagios:

   define command {
   command_name    check_http_load_time
   command_line    $USER1$/check_http_load_time.rb --perf -p /usr/local/bin/phantomjs -u $ARG1$ -w $ARG2$ -c $ARG3$
   }

8. Setup service notification (it will email me if page will load more than 8 seconds):

   define service {
       use                     local-service
       host_name               localhost
       service_description     check_http_load_time www.pctags.com
       check_command           check_http_load_time!http://www.pctags.com!8!10
       notifications_enabled   1
       contact_groups          admins
   }