Rack MultiLoader

multi_loader.rb

class MultiLoader
	def initialize(input)
		@input = input
		initial_map
	end

	def initial_map
		@map = {}
		@input.each do |host, opts|
			if opts.is_a?(String)
				reload_file = File.join(File.dirname(opts), 'restart.txt')
				if opts.end_with?('.ru')
					rackup_file = opts
				else
					rackup_file = File.join(opts, 'config.ru')
				end
			else
				dir = opts[:dir] || '.'
				rackup_file, reload_file = File.join(dir, opts[:rackup] || 'config.ru'), File.join(dir, opts[:reload] || 'restart.txt')
			end

			@map[host] = {:rackup => rackup_file, :reload => reload_file}
			reload(host)
		end
	end

	def reload(host)
		@map[host][:inst] = Object.new.instance_eval("Rack::Builder.new {( " + File.read(@map[host][:rackup]) + "\n )}")
		@map[host][:last_start] = Time.now
	end

	def needs_reload?(host)
		reload_file = @map[host][:reload]
		return false unless reload_file && File.exist?(reload_file)
		File.mtime(reload_file) > @map[host][:last_start]
	end

	def call(env)
		server_name = env['SERVER_NAME']
		raise "No configured map for domain #{server_name}" unless @map.has_key?(server_name)

		if needs_reload?(server_name)
			puts "RELOADING #{server_name}"
			reload(server_name)
		end

		@map[server_name][:inst].call(env)
	end
end


run MultiLoader.new \
	"localhost" => 'app1',
	"127.0.0.1" => 'app2.ru'