up.rb


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#!/usr/bin/env ruby

require "net/ping"
require "socket"

class Host
  def initialize s
    # example: 'nash ssh:2001 mqtt:1883'
    parts = s.split
    @hostname = parts.first
    @services_and_ports = {}
    parts.slice(1, parts.size).each { |part|
      service, port_and_protocol = part.split ":"
      port, protocol = port_and_protocol.split "/"
      @services_and_ports["#{service}/#{protocol}"] = [port.to_i, protocol]
    }
  end

  def hostname
    return @hostname
  end

  def up? hostname
    ping = Net::Ping::External.new @hostname
    ping.ping?
  end

  def service_up? service, port, protocol
    if protocol == "tcp"
      begin
        sock = TCPSocket.new @hostname, port
        sock.close
        return true
      rescue
        return false
      end
    elsif protocol == "udp"
      system "nc -u -z -w 1 #{@hostname} #{port+1} &>/dev/null"
      return $?.success?
    else
      STDERR.write "unknown protocol '#{protocol}'\n"
    end
  end

  def check
    ret = {}
    ret["up"] = up? @hostname
    return ret if not ret["up"]
    @services_and_ports.each_key { |k|
      ret[k] = service_up? k, @services_and_ports[k][0], @services_and_ports[k][1]
    }
    return ret
  end
end

def main
  while line = STDIN.gets
    h = Host.new line
    puts h.check.to_s
  end
end

if __FILE__ == $0
  main
end