Very simple munin plugin to graph nginx HTTP error codes

nginx_status_codes.rb

#!/usr/bin/env ruby

CODES = {
  '400' => 'Bad Request',
  '401' => 'Unauthorized',
  '403' => 'Forbidden',
  '404' => 'Not Found',
  '405' => 'Method Not Allowed',
  '406' => 'Not Acceptable',
  '408' => 'Request Timeout',
  '499' => 'Client Connection Terminated',
  '500' => 'Internal Server Error',
  '502' => 'Bad Gateway',
  '503' => 'Service Unavailable',
  'Other' => 'Other responses'
}

if ARGV[0] == 'config'; then
  puts "graph_title nginx Error Codes"
  puts "graph_vlabel responses per minute"
  puts "graph_category nginx"
  puts "graph_period minute"
  puts "graph_info Non-200 response codes per minute"
  CODES.each do |code, desc|
    puts "#{code}.label #{code} #{desc}"
    puts "#{code}.type DERIVE"
    puts "#{code}.min 0"
  end
else
  results = Hash[*CODES.keys.map { |k| [k, 0]}.flatten]
  File.open("/var/log/nginx/access.log").readlines.each do |line|
    if line =~ /" (\d\d\d)/
      code = $1
      if CODES.keys.include?(code)
	results[code] += 1
      elsif code.to_i >= 400
        results['Other'] += 1
      end
    end
  end
 
  results.each do |k,v|
    puts "#{k}.value #{v}"
  end 
end

Suggestion: fork this gist and add all the codes, add better log parsing (awk print $9 is unreliable)

Improved: all ruby, deals with unrecognized codes, spits out zero when no result is found.

Does this ever worked? I get Permission denied - /var/log/nginx/access.log (Errno::EACCES), regardless of how I set the file permissions (even with 644 it fails!).

@hcarvalhoalves, check the permissions on /var/log/nginx first. It's probable that the log file is readable but the directory isn't.

I have installed ruby create a file "/usr/share/munin/plugins/nginx_errors" with the above code.
Do "ln -s /usr/share/munin/plugins/nginx_errors /etc/munin/plugins/nginx_errors".
Edit "/etc/munin/plugin-conf.d/munin-node" add
[nginx_*]
user munin
command ruby %c
and restart the munin-node. But there are no Data collected (-nan).

Please can someone help?

For people who are still wondering how to fix the problem of @basti12203, you need to put smth like this in your /etc/munin/plugin-conf.d/munin-node

[nginx*]
user deployer
group adm
env.url http://localhost/nginx_status

Because I don't have ruby on my server, I wrote a python version : https://gist.github.com/bactisme/40148ca85cc82f3cf26f