#! /usr/bin/env ruby
#
#   jenkins-metrics
#
# DESCRIPTION:
#   This plugin extracts the metrics from a Jenkins Master with Metrics plugin installed
#   Anonymous user must have Metrics permissions.
#
# OUTPUT:
#    metric data
#
# PLATFORMS:
#   Linux
#
# DEPENDENCIES:
#   gem: sensu-plugin
#   gem: rest-client
#   gem: socket
#   gem: json
#
# USAGE:
#   #YELLOW
#
# NOTES:
#
# LICENSE:
#   Copyright 2015, Cornel Foltea (cornel.foltea@gmail.com)
#   Released under the same terms as Sensu (the MIT license); see LICENSE
#   for details.
#

require 'sensu-plugin/metric/cli'
require 'rest-client'
require 'socket'
require 'json'

#
# Jenkins Metrics
#
class JenkinsMetrics < Sensu::Plugin::Metric::CLI::Graphite
  SKIP_ROOT_KEYS = %w(version).freeze

  option :scheme,
         description: 'Metric naming scheme',
         short: '-s SCHEME',
         long: '--scheme SCHEME',
         default: "#{Socket.gethostname}.jenkins"

  option :server,
         description: 'Jenkins Host',
         short: '-S SERVER',
         long: '--server SERVER',
         default: 'localhost'

  option :port,
         description: 'Jenkins Port',
         short: '-p PORT',
         long: '--port PORT',
         default: '8080'

  option :uri,
         description: 'Jenkins Metrics URI',
         short: '-u URI',
         long: '--uri URI',
         default: '/metrics/currentUser/metrics'

  option :https,
         short: '-h',
         long: '--https',
         boolean: true,
         description: 'Enabling https connections',
         default: false

  option :timeout,
         short: '-t SECONDS',
         long: '--timeout SECONDS',
         description: 'Timeout for REST request',
         proc: proc(&:to_i),
         default: 10

  option :report_request_duration,
         long: '--[no-]report-request-duration',
         boolean: true,
         description: 'Report the duration of the REST request',
         default: true

  def report_request_duration
    return unless config[:report_request_duration]
    @stop ||= DateTime.now
    ms = ((@stop - @start) * 1000 * 24 * 60 * 60).to_i
    output("#{config[:scheme]}.request.duration", ms)
  end

  def run
    @start = DateTime.now
    @stop = nil
    begin
      https ||= config[:https] ? 'https' : 'http'
      r = RestClient::Resource.new("#{https}://#{config[:server]}:#{config[:port]}#{config[:uri]}", timeout: config[:timeout]).get
      @stop = DateTime.now
      all_metrics = JSON.parse(r)
      metric_groups = all_metrics.keys - SKIP_ROOT_KEYS
      metric_groups.each do |metric_groups_key|
        all_metrics[metric_groups_key].each do |metric_key, metric_value|
          metric_value.each do |metric_hash_key, metric_hash_value|
            output([config[:scheme], metric_groups_key, metric_key, metric_hash_key].join('.'), metric_hash_value) \
              if metric_hash_value.is_a?(Numeric) && (metric_hash_key == 'count' || metric_hash_key == 'value')
          end
        end
      end
      ok
    rescue Errno::ECONNREFUSED
      STDERR.write "Jenkins is not responding\n"
      critical
    rescue RestClient::RequestTimeout
      STDERR.write "Jenkins Connection timed out\n"
      critical
    ensure
      report_request_duration
    end
    ok
  end
end