#!/usr/bin/env ruby

# nagios.cfg must contain the following perfdata templates for host and service data (modified from the default
# to include hoststate / servicestate, and a fake service 'HOST' for hostperfdata, so that the
# fields match up:
#
#   host_perfdata_file_template=[HOSTPERFDATA]\t$TIMET$\t$HOSTNAME$\tHOST\t$HOSTSTATE$\t$HOSTEXECUTIONTIME$\t$HOSTLATENCY$\t$HOSTOUTPUT$\t$HOSTPERFDATA$
#
#   service_perfdata_file_template=[SERVICEPERFDATA]\t$TIMET$\t$HOSTNAME$\t$SERVICEDESC$\t$SERVICESTATE$\t$SERVICEEXECUTIONTIME$\t$SERVICELATENCY$\t$SERVICEOUTPUT$\t$SERVICEPERFDATA$
#

unless $:.include?(File.dirname(__FILE__) + '/../lib/')
  $: << File.dirname(__FILE__) + '/../lib'
end

require 'optparse'
require 'ostruct'
require 'redis'

require 'oj'
Oj.default_options = { :indent => 0, :mode => :strict }

require 'dante'

require 'flapjack/configuration'
require 'flapjack/data/event'

def process_input(opts)
  redis = opts[:redis]
  fifo  = File.new(opts[:fifo])
  begin
    while line = fifo.gets
      skip unless line
      split_line = line.split("\t")

      object_type, timestamp, entity, check, state, check_time, check_latency, check_output, check_perfdata, check_long_output = split_line

      case
      when ! (split_line.length > 8)
        puts "ERROR - rejecting this line as it doesn't split into at least 9 tab separated strings: [#{line}]"
        next
      when (timestamp !~ /^\d+$/)
        puts "ERROR - rejecting this line as second string doesn't look like a timestamp: [#{line}]"
        next
      when (not ((object_type == '[HOSTPERFDATA]') or (object_type == '[SERVICEPERFDATA]')))
        puts "ERROR - rejecting this line as first string is neither '[HOSTPERFDATA]' nor '[SERVICEPERFDATA]': [#{line}]"
        next
      end

      puts "#{object_type}, #{timestamp}, #{entity}, #{check}, #{state}, #{check_output}, #{check_long_output}"

      state = 'ok'       if state.downcase == 'up'
      state = 'critical' if state.downcase == 'down'
      details = check_long_output ? check_long_output.gsub(/\\n/, "\n") : nil
      event = {
        'entity'    => entity,
        'check'     => check,
        'type'      => 'service',
        'state'     => state,
        'summary'   => check_output,
        'details'   => details,
        'perfdata'  => check_perfdata,
        'time'      => timestamp,
      }
      Flapjack::Data::Event.add(event, :redis => redis)
    end
  rescue Redis::CannotConnectError
    puts "Error, unable to to connect to the redis server (#{$!})"
  end
end

def main(opts)
  fifo = opts[:fifo]
  redis = Redis.new(opts[:redis_options])
  while true
    process_input(:redis => redis, :fifo => fifo)
    puts "Whoops with the fifo, restarting main loop in 10 seconds"
    sleep 10
  end
end

options = OpenStruct.new
options.config    = Flapjack::Configuration::DEFAULT_CONFIG_PATH
options.daemonize = nil

exe = File.basename(__FILE__)

optparse = OptionParser.new do |opts|
  opts.banner = "Usage: #{exe} COMMAND [OPTIONS]"

  opts.separator  ""
  opts.separator  "Commands"
  opts.separator  "     start #{" " * 25} start #{exe}"
  opts.separator  "     stop #{" " * 26} stop #{exe}"
  opts.separator  "     restart #{" " * 23} (re)start #{exe}"
  opts.separator  "     status #{" " * 24} see if #{exe} is running"
  opts.separator  ""
  opts.separator  "Options"

  opts.on("-c", "--config [PATH]", String, "PATH to the config file to use") do |c|
    options.config = c
  end

  opts.on("-f", "--fifo FIFO", String, "Path to the nagios perfdata named pipe") do |f|
    options.fifo = f
  end

  opts.on("-d", "--[no-]daemonize", "Daemonize?") do |d|
    options.daemonize = d
  end

  opts.on("-p", "--pidfile [PATH]", String, "PATH to the pidfile to write to") do |pid|
    options.pidfile = pid
  end

  opts.on("-l", "--logfile [PATH]", String, "PATH to the logfile to write to") do |l|
    options.logfile = l
  end

  opts.on_tail("-h", "--help", "Show this usage message") do
    puts opts
    puts '
Required Nagios Configuration Changes
-------------------------------------

flapjack-nagios-receiver reads events from a named pipe written to by Nagios. The named pipe needs creating, and Nagios needs to be told to write performance data output to it.

To create the named pipe:

  mkfifo -m 0666 /var/cache/nagios3/event_stream.fifo

nagios.cfg changes:

  # modified lines:
  enable_notifications=0
  host_perfdata_file=/var/cache/nagios3/event_stream.fifo
  service_perfdata_file=/var/cache/nagios3/event_stream.fifo
  host_perfdata_file_template=[HOSTPERFDATA]\t$TIMET$\t$HOSTNAME$\tHOST\t$HOSTSTATE$\t$HOSTEXECUTIONTIME$\t$HOSTLATENCY$\t$HOSTOUTPUT$\t$HOSTPERFDATA$
  service_perfdata_file_template=[SERVICEPERFDATA]\t$TIMET$\t$HOSTNAME$\t$SERVICEDESC$\t$SERVICESTATE$\t$SERVICEEXECUTIONTIME$\t$SERVICELATENCY$\t$SERVICEOUTPUT$\t$SERVICEPERFDATA$
  host_perfdata_file_mode=p
  service_perfdata_file_mode=p

Details on the wiki: https://github.com/flapjack/flapjack/wiki/USING#configuring-nagios
'

    exit
  end

end
optparse.parse!(ARGV)

FLAPJACK_ENV = ENV['FLAPJACK_ENV'] || 'production'

config = Flapjack::Configuration.new
config.load(options.config)
config_env = config.all
redis_options = config.for_redis

if config_env.nil? || config_env.empty?
  puts "No config data for environment '#{FLAPJACK_ENV}' found in '#{options.config}'"
  puts optparse
  exit 1
end

config_nr = config_env['nagios-receiver'] || {}

pidfile = options.pidfile.nil? ?
            (config_nr['pid_file'] || "/var/run/flapjack/#{exe}.pid") :
            options.pidfile

logfile = options.logfile.nil? ?
            (config_nr['log_file'] || "/var/log/flapjack/#{exe}.log") :
            options.logfile

fifo = options.fifo.nil? ?
         (config_nr['fifo'] || '/var/cache/nagios3/event_stream.fifo') :
         options.fifo

daemonize = options.daemonize.nil? ?
              !!config_nr['daemonize'] :
              options.daemonize


runner = Dante::Runner.new(exe, :pid_path => pidfile, :log_path => logfile)
case ARGV[0]
when "start", "restart"
  unless File.exist?(fifo)
    raise "No fifo (named pipe) file found at #{fifo}"
  end
  unless File.pipe?(fifo)
    raise "The file at #{fifo} is not a named pipe, try using mkfifo to make one"
  end
  unless File.readable?(fifo)
    raise "The fifo (named pipe) at #{fifo} is unreadable"
  end
end

case ARGV[0]
when "start"
  if runner.daemon_running?
    puts "#{exe} is already running."
    exit 1
  else
    print "#{exe} starting..."
    runner.execute(:daemonize => daemonize) {
      main(:redis_options => redis_options, :fifo => fifo)
    }
    puts " done."
  end

when "stop"
  if runner.daemon_running?
    print "#{exe} stopping..."
    runner.execute(:kill => true)
    puts " done."
  else
    puts "#{exe} is not running."
    exit 1
  end

when "restart"
  print "#{exe} restarting..."
  runner.execute(:daemonize => true, :restart => true) {
    main(:redis_options => redis_options, :fifo => fifo)
  }
  puts " done."

when "status"
  uptime = (runner.daemon_running?) ? Time.now - File.stat(pidfile).ctime : 0
  if runner.daemon_running?
    puts "#{exe} is running: #{uptime}"
  else
    puts "#{exe} is not running"
    exit 3
  end

else
  if ARGV.nil? || ARGV.empty?
    puts "No command provided"
  else
    puts "Unknown command provided: '#{ARGV[0]}'"
  end
  puts "\n#{optparse}"
  exit 1

end