pxesrv

#!/usr/bin/env ruby

require 'erb'
require 'pathname'
require 'pp'
require 'sinatra'
require 'yaml'

configure do

  # listen on all interfaces
  set :bind, '0.0.0.0'

  config_file = nil
  config_env = 'PXESRV_CONF'
  if ENV.has_key? config_env
    config_file = ENV[config_env]
  end

  root_path = nil
  root_env = 'PXESRV_ROOT'
  if ENV.has_key? root_env
    root_path = ENV[root_env]
  end

  # if the service root path has been defined
  if root_path.nil? or not File.directory? root_path
    $stderr.puts "Make sure to set $PXESRV_ROOT"
    exit 1
  end

  default_response = "#{root_path}/default"
  once_path = "#{root_path}/once"
  static_path = "#{root_path}/static"
  grub_path = "#{root_path}/grub"

  # Sets the document root for serving static files:
  set :root_path, root_path
  set :public_folder, root_path
  set :once_path, once_path
  set :static_path, static_path
  set :grub_path, grub_path
  set :default_response, default_response

  # Do not show exceptions
  set :show_exceptions, false

  # default location of the service log
  log_file = '/var/log/pxesrv.log'
  # an environment variable may define an alternative 
  log_env = 'PXESRV_LOG'
  log_file = ENV[log_env] if ENV.has_key? log_env

  # Log to file (ref: http://recipes.sinatrarb.com/p/middleware/rack_commonlogger)
  log_handel = File.new(log_file, 'a+')
  log_handel.sync = true
  use Rack::CommonLogger, log_handel

  $stdout.puts "pxesrv_root=#{root_path}\npxesrv_log=#{log_file}"
  $stdout.puts "pxesrv_default_response=#{default_response}\npxesrv_once_path=#{once_path}\npxesrv_static_path=#{static_path}"
end

# Server will always return contents in text format:
before do
  content_type :txt
end

#
# Installation with iPXE 
#

# Basic route name as configured in the 'Filename' option on the DHCP server.
get '/redirect' do

  ip = request.ip
  response = settings.default_response

  # check if the client should be redirected once
  path = "#{settings.once_path}/#{ip}"
  if File.symlink?(path)
    response = File.readlink(Pathname.new(path).expand_path)
    File.delete(path) # remove the symlink
  # check if a static client redirect exists
  else
    logger.info "Missing #{path}"
    # check if a static redirect exists
    path  = "#{settings.static_path}/#{ip}"
    if File.exist?(path)
      # send the client to a static boot configuration
      response = path
    else
      logger.info "Missing #{path}"
    end
  end

  # redirect node to target configuration
  logger.info "Redirect #{ip} to #{response}"
  send_file(response)

end

#
# Installation with pxelinux
#

# Default route:
get '/pxelinux.cfg/default' do
  send_file(settings.public_dir + '/pxelinux.cfg/default')
end

#
# Remove a Grub configuration file from the server 
#
get '/grub/clear/:version' do
  response = settings.default_response
  # convert client IP to hexadecimal notation
  hex = '%02X%02X%02X%02X' % request.ip.split('.')
  # construct the target Grub configuration file path
  path = "#{settings.grub_path}/#{params[:version]}/grub.cfg-#{hex}"
  logger.debug "grub/clear #{path}"
  if File.exists?(path) 
    File.delete(path)
    status 200
    body "Delete #{path}"
  else
    status 400
    body "Missing #{path}"
  end

end

# ERB template installation:
get '/pxelinux.cfg/:name' do
end

# Gracefully handle 404 errors:
not_found do
  "The requested route is not available"
end