wait_for_port, a simple way to wait for a port to be open/closed

wait_for_port.gemspec

Gem::Specification.new do |s|
  s.name        = 'wait_for_port'
  s.version     = '0.1.0'
  s.platform    = Gem::Platform::RUBY
  s.author      = 'John Bintz'
  s.email       = '[email protected]'
  s.summary     = 'Wait for a port to be open or not open.'
  s.description = 'Wait for a port to be open or not open.'

  s.files         = ['wait_for_port.rb']
  s.require_path  = '.'
end

wait_for_port.rb

require 'socket'

module WaitForPort
    def open?(*args)
      wait_for_port(*args)
      true
    rescue => e
      false
    end

    def closed?(*args)
      wait_for_not_port(*args)
      true
    rescue => e
      false
    end

    def wait_for_port(port, host = '127.0.0.1', timeout = 5)
      if block_given?
        return if open?(port, host, 1)
        yield
      end

      begin
        connected = false
        begin
          TCPSocket.new(host, port)
          connected = true
        rescue => e
          timeout -= 1
          raise e if timeout == 0

          sleep 1
        end
      end while !connected
    end

    def wait_for_not_port(port, host = '127.0.0.1', timeout = 5)
      if block_given?
        return if closed?(port, host, 1)
        yield
      end

      begin
        down = false
        begin
          TCPSocket.new(host, port)

          timeout -= 1
          raise StandardError.new if timeout == 0

          sleep 1
        rescue => e
          down = true
        end
      end while !down
    end

  extend self
end