#!/usr/bin/env ruby

require 'pathname'
ENV['BUNDLE_GEMFILE'] ||= File.expand_path("../../Gemfile",
  Pathname.new(__FILE__).realpath)
$LOAD_PATH << File.expand_path("../../lib",
  Pathname.new(__FILE__).realpath)
require 'rubygems'
require 'bundler'
require 'bundler/setup'
require "optparse"
require "rest-client"
require "json"

EXIT_OK = 0
EXIT_WARNING = 1
EXIT_CRITICAL = 2
EXIT_UNKNOWN = 3

options = {}

optparse = OptionParser.new do |opts|
  opts.banner = "Usage: check_graphite.rb [options]"

  options[:name] = 'value'
  opts.on("-n", "--name NAME", "Descriptive name") do |name|
    options[:name] = name
  end
  options[:url] = nil
  opts.on("-u", "--url URL", "Target url") do |url|
    options[:url] = url
  end
  options[:metric] = nil
  opts.on("-m", "--metric NAME", "Metric path string") do |metric|
    options[:metric] = metric
  end
  options[:duration] = 5
  opts.on("-d", "--duration LENGTH", "Length, in minute of data to parse (default: 5)") do |duration|
    options[:duration] = duration
  end
  options[:warning] = nil
  opts.on("-w", "--warning VALUE", "Warning threshold") do |warning|
    options[:warning] = warning
  end
  options[:critical] = nil
  opts.on("-c", "--critical VALUE", "Critical threshold") do |critical|
    options[:critical] = critical
  end
  opts.on( "-h", "--help", "Display this screen" ) do
    puts opts
    exit
  end
end

begin
  optparse.parse!
  mandatory = [:url, :metric, :warning, :critical]
  missing = mandatory.select { |param| options[param].nil? }
  if not missing.empty?
    puts "Missing options: #{missing.join(', ')}"
    puts optparse
    exit 3
  end
rescue OptionParser::InvalidOption, OptionParser::MissingArgument
  puts $!.to_s
  puts optparse
  exit 3
end

base_url = options[:url]
metric = options[:metric]
duration = options[:duration].to_s
url = base_url + "/render/?target=" + metric + "&format=json&from=-" + duration + "mins"

data = {}
data["total"] = 0

begin
  JSON.parse(RestClient.get(url)).each do |cache|
    data["#{cache['target']}"] = 0
    count = 0
    cache["datapoints"].each do |point|
      unless (point[0].nil?)
        data["#{cache['target']}"] += point[0]
        count += 1
      end
    end
    data["#{cache['target']}"] /= count
    data["total"] += data["#{cache['target']}"]
  end
rescue ZeroDivisionError => e
  puts "UNKNOWN metric not in graphite!"
  exit EXIT_UNKNOWN
rescue => e
  puts e.message
  exit EXIT_CRITICAL
end

total           = data["total"].to_f
formatted_total = sprintf("%.2f", total)

if (options[:critical].to_f > options[:warning].to_f)
  if (total >= options[:critical].to_f)
    puts "CRITICAL #{options[:name]}: #{formatted_total}"
    exit EXIT_CRITICAL
  elsif (total >= options[:warning].to_f)
    puts "WARNING #{options[:name]}: #{formatted_total}"
    exit EXIT_WARNING
  else
    puts "OK #{options[:name]}: #{formatted_total}"
    exit EXIT_OK
  end
else
  if (total <= options[:critical].to_f)
    puts "CRITICAL #{options[:name]}: #{formatted_total}"
    exit EXIT_CRITICAL
  elsif (total <= options[:warning].to_f)
    puts "WARNING #{options[:name]}: #{formatted_total}"
    exit EXIT_WARNING
  else
    puts "OK #{options[:name]}: #{formatted_total}"
    exit EXIT_OK
  end
end