sensu-basic-mon

#!/usr/bin/env ruby
#
# As my coworker often says: who monitors the monitoring?
#
# Or: Quis custodiet ipsos custodes?
#
# Basic monitoring of Sensu via the VIA. Meant to be run as a cron job.
# This script is meant to be run as a CRON.
#
# Written by Jean-Francois Theroux <jtheroux@lapresse.ca>

require "rubygems"
require "net/http"
require "json"

sensu_host = "localhost"
sensu_port = "4567"
fqdn = `hostname -f`.chomp()
pid_file = '/var/run/sensu/sensu-server.pid' # Location set by the official sensu-chef cookbook.

# API/Redis/RabbitMQ monitoring
begin
  res = Net::HTTP.get_response(URI("http://#{sensu_host}:#{sensu_port}/info"))
  if JSON.parse(res.body)["health"]["redis"] == "down"
    puts "Redis is down on #{fqdn}!"
  end

  if JSON.parse(res.body)["health"]["rabbitmq"] == "down"
    puts "RabbitMQ is down on #{fqdn}!"
  end
rescue Errno::ECONNREFUSED
  puts "Sensu API is down on #{fqdn}! Redis and RabbitMQ might be down as well."
end

# Server process monitoring
begin
  Process.kill(0, File.read(pid_file).to_i)
rescue Errno::EPERM
  puts "You should run this script as root!"
rescue Errno::ESRCH
  puts "Sensu-server is down on #{fqdn}!"
rescue Errno::ENOENT
  puts "Sensu-server is down on #{fqdn}!"
end