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How do you integrate Resque in Cucumber features?

开发者 https://www.devze.com 2023-03-14 15:06 出处:网络
I\'ve been trying to apply Square\'s method of including Resque in their integration tests without much luck. I\'m not sure if Resque and/or Cucumber has 开发者_JAVA技巧changed a lot since August 2010

I've been trying to apply Square's method of including Resque in their integration tests without much luck. I'm not sure if Resque and/or Cucumber has 开发者_JAVA技巧changed a lot since August 2010.

Below you find the approach I took, and perhaps you can either:

  1. Tell me where I went wrong, and how I can fix it
  2. Recommend a completely new way of integrating Resque into Cucumber features

What I did to install it

Square's blog post didn't have explicit steps on how to install it, so this is what I did:

  1. Downloaded their gist into features/support/cucumber_external_resque_worker.rb
  2. Created a Rails initializer at config/initializers/cucumber_external_resque.rb that did the following:
    1. require 'features/support/cucumber_external_resque_worker'
    2. CucumberExternalResqueWorker.install_hooks_on_startup
  3. In cucumber_external_resque_worker.rb, I changed instances of Rails.env.cucumber? to Rails.env.test? because Cucumber was running the features in the test environment (I did some puts Rails.env in cucumber_external_resque_worker.rb to be sure.
  4. I run the features. At this point, I get stuck because I get the error uninitialized constant WorkerBase (NameError). Perhaps Resque has changed the way it names things.

Thanks in advance!


You can just run the Resque job synchronously by setting

Resque.inline = true

I added this line to my config/initializers/resque.rb:

Resque.inline = Rails.env.test?

It's more concise than the other approaches suggested in the post. As it is synchronous, it will be a little slower.


I spent a while toying with this today, and I think I have a solution.

Here's an updated Gist that removes the need for WorkerBase.

It also includes the config changes necessary to get things working (which are identical to the changes you discovered).


# This is adapted from this gist: https://gist.github.com/532100 by Square
# The main difference is that it doesn't require Bluth for WorkerBase
# It also calls prune_dead_workers on start so it doesn't hang on every other run
# It does not do anything special to avoid connecting to your main redis instance; you should be
# doing that elsewhere

class CucumberExternalResqueWorker
  DEFAULT_STARTUP_TIMEOUT = 1.minute
  COUNTER_KEY = "cucumber:counter"

  class << self
    attr_accessor :pid, :startup_timeout

    def start
      # Call from a Cucumber support file so it is run on startup
      return unless Rails.env.test?
      if self.pid = fork
        start_parent
        wait_for_worker_to_start
      else
        start_child
      end
    end

    def install_hooks_on_startup
      # Call from a Rails initializer
      return unless Rails.env.test?
      # Because otherwise crashed workers cause a fork and we pause the actual worker forever
      Resque::Worker.all.each { |worker| worker.prune_dead_workers }
      install_pause_on_start_hook
      install_worker_base_counter_patch
    end

    def process_all
      # Call from a Cucumber step
      unpause
      sleep 1 until done?
      pause
    end

    def incr
      Resque.redis.incr(COUNTER_KEY)
    end

    def decr
      Resque.redis.decr(COUNTER_KEY)
    end

    def reset_counter
      Resque.redis.set(COUNTER_KEY, 0)
    end

    private

    def done?
      Resque.redis.get(CucumberExternalResqueWorker::COUNTER_KEY).to_i.zero?
    end

    def pause(pid = self.pid)
      return unless Rails.env.test?
      Process.kill("USR2", pid)
    end

    def unpause
      return unless Rails.env.test?
      Process.kill("CONT", pid)
    end

    def start_parent
      at_exit do
        #reset_counter
        Process.kill("KILL", pid) if pid
      end
    end

    def start_child
      # Array form of exec() is required here, otherwise the worker is not a direct child process of cucumber.
      # If it's not the direct child process then the PID returned from fork() is wrong, which means we can't
      # communicate with the worker.
      exec('rake', 'resque:work', "QUEUE=*", "RAILS_ENV=test", "VVERBOSE=1")
    end

    def wait_for_worker_to_start
      self.startup_timeout ||= DEFAULT_STARTUP_TIMEOUT
      start = Time.now.to_i
      while (Time.now.to_i - start) < startup_timeout
        return if worker_started?
        sleep 1
      end

      raise "Timeout while waiting for the worker to start. Waited #{startup_timeout} seconds."
    end

    def worker_started?
      Resque.info[:workers].to_i > 0
    end

    def install_pause_on_start_hook
      Resque.before_first_fork do
        #reset_counter
        pause(Process.pid)
      end
    end

    def install_worker_base_counter_patch
      Resque.class_eval do
        class << self
          def enqueue_with_counters(*args, &block)
            CucumberExternalResqueWorker.incr
            enqueue_without_counters(*args, &block)
          end
          alias_method_chain :enqueue, :counters
        end
      end
      Resque::Job.class_eval do
        def perform_with_counters(*args, &block)
          perform_without_counters(*args, &block)
        ensure
          CucumberExternalResqueWorker.decr
        end
        alias_method_chain :perform, :counters
      end
    end
  end
end

In the Cucumber environment file features/support/env.rb

After:

require 'cucumber/rails'

Add:

require 'lib/cucumber_external_resque_worker'
CucumberExternalResqueWorker.start

Change:

  DatabaseCleaner.strategy = :transaction

to:

  DatabaseCleaner.strategy = :truncation

Also, create a file: config/initializers/cucumber_external_resque.rb

require 'lib/cucumber_external_resque_worker'
CucumberExternalResqueWorker.install_hooks_on_startup
# In my controller, I have:
  def start
    if params[:job] then
      Resque.enqueue(DemoJob, j.id)
    end
    redirect_to :action => :index
  end
# DemoJob:
class DemoJob
  def self.queue
    :demojob
  end
  def perform(job_id)
    j = Job.find(job_id)
    j.value = "done"
    j.save
  end
# In your actual Cucumber step file, for instance:
When /I click the start button for "([^"]*)"/ do |jobname|
  CucumberExternalResqueWorker.reset_counter
  Resque.remove_queue(DemoJob.queue)
  click_button(jobname)
end
When /all open jobs are processed/ do
  CucumberExternalResqueWorker.process_all
end

# And you cucumber feature file looks like:
# Scenario: Starting a job
#   When I click the start button for "Test Job 1"
#     And all open jobs are processed
#   Then I am on the job index page
#     And I should see an entry for "Test Job 1" with a value of "done".


I'm trying the approach described here:

Cucumber and Resque Jobs

which performs the resque processing synchronously. In my case, I'm not interested in testing Resque, I just want to test the functionality in my application.

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