Add before & after dequeue hooks.

Author: humancopy

lib/resque.rb

@@ -265,7 +265,17 @@ def enqueue(klass, *args)
   #
   # This method is considered part of the `stable` API.
   def dequeue(klass, *args)
+    # Perform before_dequeue hooks. Don't perform dequeue if any hook returns false
+    before_hooks = Plugin.before_dequeue_hooks(klass).collect do |hook|
+      klass.send(hook, *args)
+    end
+    return if before_hooks.any? { |result| result == false }
+
     Job.destroy(queue_from_class(klass), klass, *args)
+
+    Plugin.after_dequeue_hooks(klass).each do |hook|
+      klass.send(hook, *args)
+    end
   end
 
   # Given a class, try to extrapolate an appropriate queue based on a

lib/resque/plugin.rb

@@ -52,5 +52,15 @@ def after_enqueue_hooks(job)
     def before_enqueue_hooks(job)
       job.methods.grep(/^before_enqueue/).sort
     end
+
+    # Given an object, returns a list `after_dequeue` hook names.
+    def after_dequeue_hooks(job)
+      job.methods.grep(/^after_dequeue/).sort
+    end
+
+    # Given an object, returns a list `before_dequeue` hook names.
+    def before_dequeue_hooks(job)
+      job.methods.grep(/^before_dequeue/).sort
+    end
   end
 end

test/job_hooks_test.rb

@@ -290,6 +290,68 @@ def self.perform(history)
   end
 end
 
+context "Resque::Job after_dequeue" do
+  include PerformJob
+
+  class ::AfterDequeueJob
+    @queue = :jobs
+    def self.after_dequeue_record_history(history)
+      history << :after_dequeue
+    end
+
+    def self.perform(history)
+    end
+  end
+
+  test "the after dequeue hook should run" do
+    history = []
+    @worker = Resque::Worker.new(:jobs)
+    Resque.dequeue(AfterDequeueJob, history)
+    @worker.work(0)
+    assert_equal history, [:after_dequeue], "after_dequeue was not run"
+  end
+end
+
+
+context "Resque::Job before_dequeue" do
+  include PerformJob
+
+  class ::BeforeDequeueJob
+    @queue = :jobs
+    def self.before_dequeue_record_history(history)
+      history << :before_dequeue
+    end
+
+    def self.perform(history)
+    end
+  end
+
+  class ::BeforeDequeueJobAbort
+    @queue = :jobs
+    def self.before_dequeue_abort(history)
+      false
+    end
+
+    def self.perform(history)
+    end
+  end
+
+  test "the before dequeue hook should run" do
+    history = []
+    @worker = Resque::Worker.new(:jobs)
+    Resque.dequeue(BeforeDequeueJob, history)
+    @worker.work(0)
+    assert_equal history, [:before_dequeue], "before_dequeue was not run"
+  end
+
+  test "a before dequeue hook that returns false should prevent the job from getting queued" do
+    history = []
+    @worker = Resque::Worker.new(:jobs)
+    Resque.dequeue(BeforeDequeueJobAbort, history)
+    assert_equal 0, Resque.size(:jobs)
+  end
+end
+
 context "Resque::Job all hooks" do
   include PerformJob