Check for assumed infrastructure

sanity_check.rb

#!/usr/bin/env ruby
# Encoding: UTF-8

require 'socket'
def listening? host, port
  TCPSocket.open(host, port)#.close
  true
rescue
  false
end

def command_runs? command
  system "#{command} > /dev/null 2>&1"
end

ESC = "\e["

NND   = "#{ESC}0m"
GREEN = "#{ESC}32m"
RED   = "#{ESC}1;31m"
BOLD  = "#{ESC}1m"

OK = GREEN + "✓" + NND
FAIL = RED + "✗" + NND
REPORT = "Checking %s "

def format component
  REPORT % (BOLD + component.to_s + NND)
end

def max_component_width
  @components.keys.map(&:size).max
end

def padding_for component
  " " * (max_component_width - component.size)
end

def check_component component, check
  print padding_for(component)
  print format(component)
  puts check.call ? OK : FAIL
end

@components = {}
def check component, &block
  @components[component] = block
end

at_exit do
  @components.each do |component, check|
    check_component(component, check)
  end
end

check :rabbitmq do
  command_runs? "rabbitmqctl list_queues"
end

check :redis do
  listening? "localhost", 6379
end

check :mysql do
  command_runs? "echo | mysql -uroot"
end

check :phantomjs do
  command_runs? "phantomjs --version"
end

check :node do
  command_runs? "node --version"
end