discover_host

#!/usr/bin/env ruby

require 'fileutils'
require 'net/http'
require 'net/https'
require 'uri'

# For comparison
require 'rubygems'
require 'facter'
require 'yaml'

def discover_server
  server = (discover_by_pxe or discover_by_dns)
  unless server =~ /^http/
    server = "http://#{server}"
  end
  server
end

def discover_by_pxe
  begin
    contents = File.open("/proc/cmdline", 'r') { |f| f.read }
    server_ip = contents.split.map { |x| $1 if x.match(/foreman.ip=(.*)/)}.compact
    if server_ip.size == 1
      return server_ip.join
    else
      return false
    end
  rescue
    return false
  end
end

def discover_by_dns
  begin
    contents = File.open("/proc/cmdline", 'r') { |f| f.read }
    server_name = contents.split.map { |x| $1 if x.match(/foreman.server=(.*)/)}.compact
    server_name = server_name.size == 1 ? server_name.join : 'foreman'

    require 'socket'
    return TCPSocket.gethostbyname(server_name)[3..-1].first || false
  rescue
    return false
  end
end

def upload
  puts "#{Time.now}: Triggering import of facts from Foreman"
  ip = Facter.value('ipaddress') 
  data = ip.nil? ? {} : {'ip' => ip}
  begin
    uri = URI.parse(discover_server)
    http = Net::HTTP.new(uri.host, uri.port)
    if uri.scheme == 'https' then
      http.use_ssl = true
      http.verify_mode = OpenSSL::SSL::VERIFY_NONE
    end
    req = Net::HTTP::Post.new("/discovers")
    req.set_form_data(data)
    response = http.request(req)
    puts response.body
  rescue Exception => e
    raise "#{Time.now}: Could not send facts to Foreman: #{e}"
  end
end

def write_cache(data)
  File.open('/tmp/proxy_cache', 'w') {|f| f.write(data) }
end

def read_cache
  File.read('/tmp/proxy_cache')
rescue => e
  "empty cache"
end

# Main

$stdout.reopen("/tmp/proxy-discovery.log", "w")
$stderr.reopen("/tmp/proxy-discovery.err", "w")

# loop, but only upload on changes
while true do
  uninteresting_facts=/kernel|operatingsystem|osfamily|ruby|path|time|swap|free|filesystem|version|selinux/i
  facts = Facter.to_hash.reject! {|k,v| k =~ uninteresting_facts }
  unless YAML.load(read_cache) == facts
    puts "Fact cache invalid, reloading to foreman"
    upload
    write_cache(YAML.dump(facts))
  end
  sleep 60
end