README.md

Typhoeus Thread Deadlock Example

It works when running a server in a separate process:

$ bundle exec ruby example.rb
Booted sinatra app
Using typhoeus to make a request to the app...
Response: hello world

...but if you run the server in a separate thread in the same process as the client, it deadlocks:

$ THREADED=1 bundle exec ruby example.rb

ctrl-c won't even kill it. You've got to kill -9 it to stop it.

This used to work with Typhoeus 0.3 and 0.4.

example.rb

require './localhost_server'
require 'sinatra/base'
app = Sinatra.new do
  get('/') { "hello world" }
end

LocalhostServer.new(app.new, 8888)

puts "Booted sinatra app"

require 'typhoeus'

puts "Using typhoeus to make a request to the app..."

request = Typhoeus::Request.new("http://localhost:8888/", :method => :get)
request.run
puts "Response: #{request.response.body}"

Gemfile

# A sample Gemfile
source "https://rubygems.org"

gem 'typhoeus', git: 'git://github.com/typhoeus/typhoeus.git'
gem 'sinatra'

Gemfile.lock

GIT
  remote: git://github.com/typhoeus/typhoeus.git
  revision: 73ef1a00c2615cf77e92591c1efd885ffafb16b6
  specs:
    typhoeus (0.5.0.rc)
      ethon (= 0.5.0)

GEM
  remote: https://rubygems.org/
  specs:
    ethon (0.5.0)
      ffi (~> 1.0.11)
      mime-types (~> 1.18)
    ffi (1.0.11)
    mime-types (1.19)
    rack (1.4.1)
    rack-protection (1.2.0)
      rack
    sinatra (1.3.2)
      rack (~> 1.3, >= 1.3.6)
      rack-protection (~> 1.2)
      tilt (~> 1.3, >= 1.3.3)
    tilt (1.3.3)

PLATFORMS
  ruby

DEPENDENCIES
  sinatra
  typhoeus!

localhost_server.rb

require 'rack'
require 'rack/handler/webrick'
require 'net/http'

# The code for this is inspired by Capybara's server:
#   http://github.com/jnicklas/capybara/blob/0.3.9/lib/capybara/server.rb
class LocalhostServer
  READY_MESSAGE = "Server ready"

  class Identify
    def initialize(app)
      @app = app
    end

    def call(env)
      if env["PATH_INFO"] == "/__identify__"
        [200, {}, [LocalhostServer::READY_MESSAGE]]
      else
        @app.call(env)
      end
    end
  end

  attr_reader :port

  def initialize(rack_app, port = nil)
    @port = port || find_available_port
    @rack_app = rack_app
    concurrently { boot }
    wait_until(10, "Boot failed.") { booted? }
  end

  private

  def find_available_port
    server = TCPServer.new('127.0.0.1', 0)
    server.addr[1]
  ensure
    server.close if server
  end

  def boot
    # Use WEBrick since it's part of the ruby standard library and is available on all ruby interpreters.
    options = { :Port => port }
    options.merge!(:AccessLog => [], :Logger => WEBrick::BasicLog.new(StringIO.new)) unless ENV['VERBOSE_SERVER']
    Rack::Handler::WEBrick.run(Identify.new(@rack_app), options)
  end

  def booted?
    res = ::Net::HTTP.get_response("localhost", '/__identify__', port)
    if res.is_a?(::Net::HTTPSuccess) or res.is_a?(::Net::HTTPRedirection)
      return res.body == READY_MESSAGE
    end
  rescue Errno::ECONNREFUSED, Errno::EBADF
    return false
  end

  def concurrently
    if should_use_subprocess?
      pid = Process.fork do
        trap(:INT) { ::Rack::Handler::WEBrick.shutdown }
        yield
        exit # manually exit; otherwise this sub-process will re-run the specs that haven't run yet.
      end

      at_exit do
        Process.kill('INT', pid)
        begin
          Process.wait(pid)
        rescue Errno::ECHILD
          # ignore this error...I think it means the child process has already exited.
        end
      end
    else
      Thread.new { yield }
    end
  end

  def should_use_subprocess?
    !ENV['THREADED']
  end

  def wait_until(timeout, error_message, &block)
    start_time = Time.now

    while true
      return if yield
      raise TimeoutError.new(error_message) if (Time.now - start_time) > timeout
      sleep(0.05)
    end
  end
end