#!/usr/bin/env ruby
require 'rubygems'
require 'fog'
require 'date'
require 'time'
require 'json'

require File.expand_path('../../lib/riemann/tools', __FILE__)

$0 = __FILE__ # Let's not expose our AWS keys in the process list

class Riemann::Tools::AWS
  include Riemann::Tools

  opt :access_key, "AWS access key", :type => String
  opt :secret_key, "Secret access key", :type => String
  opt :region, "AWS region", :type => String, :default => 'eu-west-1'
  opt :dbinstance_identifier, "DBInstanceIdentifier", :type => String
  def initialize
    abort "FATAL: specify a DB instance name, see --help for usage" unless opts[:dbinstance_identifier]
    @cloudwatch = Fog::AWS::CloudWatch.new(:aws_access_key_id => opts[:access_key],
                                           :aws_secret_access_key => opts[:secret_key],
                                           :region => opts[:region])
  end

  def tick
    time = Time.new
    ['DatabaseConnections', 'FreeableMemory', 'FreeStorageSpace', 'NetworkReceiveThroughput', 'NetworkTransmitThroughput', 'ReadThroughput', 'CPUUtilization'].each do |metric|
      result = @cloudwatch.get_metric_statistics({"Namespace" => 'AWS/RDS', "MetricName" => "#{metric}", "Statistics" => 'Average', "Dimensions" => [{"Name" => "DBInstanceIdentifier", "Value" => "#{opts[:dbinstance_identifier]}"}], "StartTime" => (time-120).to_time.iso8601, "EndTime" => time.to_time.iso8601, "Period" => 60})
      metricsResult = result.data[:body]['GetMetricStatisticsResult']
      puts JSON.dump(metricsResult)
      if (metricsResult['Datapoints'].length>0)
        datapoint = metricsResult['Datapoints'][0]
        ev = {:metric => datapoint['Average'],
              :service => "#{opts[:dbinstance_identifier]}.#{metric} (#{datapoint['Unit']})",
              :description => JSON.dump(metricsResult),
              :state => "ok",
              :ttl => 300}


        report ev
      end

    end
  end
end

Riemann::Tools::AWS.run