Add before_pause, and after_pause hooks to be run when the worker is paused

Author: ecoffey

lib/resque.rb

@@ -121,6 +121,24 @@ def after_fork(&block)
   # Set the after_fork proc.
   attr_writer :after_fork
 
+  # The `before_pause` hook will be run in the parent process before the
+  # worker has paused processing (via #pause_processing or SIGUSR2).
+  def before_pause(&block)
+    block ? (@before_pause = block) : @before_pause
+  end
+
+  # Set the after_pause proc.
+  attr_writer :before_pause
+
+  # The `after_pause` hook will be run in the parent process after the
+  # worker has paused (via SIGCONT).
+  def after_pause(&block)
+    block ? (@after_pause = block) : @after_pause
+  end
+
+  # Set the after_continue proc.
+  attr_writer :after_pause
+
   def to_s
     "Resque Client connected to #{redis_id}"
   end

lib/resque/worker.rb

@@ -358,8 +358,10 @@ def pause
         wr.write 'x'
         wr.close
       }
+      run_hook :before_pause, self
       rd.read 1
       rd.close
+      run_hook :after_pause, self
     end
 
     # Stop processing jobs after the current one has completed (if we're

test/worker_test.rb

@@ -470,6 +470,52 @@ def self.perform
     assert_not_equal original_connection, Resque.redis.client.connection.instance_variable_get("@sock")
   end
 
+  it "Will call before_pause before it is paused" do
+    $BEFORE_PAUSE_CALLED = false
+    $CAPTURED_WORKER = nil
+
+    Resque.before_pause do |worker|
+      $BEFORE_PAUSE_CALLED = true
+      $CAPTURED_WORKER = worker
+    end
+
+    @worker.instance_variable_set(:@paused, true)
+
+    assert !$BEFORE_PAUSE_CALLED
+
+    t = Thread.start { sleep(1); Process.kill('CONT', @worker.pid) }
+
+    @worker.work(0)
+
+    t.join
+
+    assert $BEFORE_PAUSE_CALLED
+    assert_equal @worker, $CAPTURED_WORKER
+  end
+
+  it "Will call after_pause after it is paused" do
+    $AFTER_PAUSED_CALLED = false
+    $CAPTURED_WORKER = nil
+
+    Resque.after_pause do |worker|
+      $AFTER_PAUSED_CALLED = true
+      $CAPTURED_WORKER = worker
+    end
+
+    @worker.instance_variable_set(:@paused, true)
+
+    assert !$AFTER_PAUSED_CALLED
+
+    t = Thread.start { sleep(1); Process.kill('CONT', @worker.pid) }
+
+    @worker.work(0)
+
+    t.join
+
+    assert $AFTER_PAUSED_CALLED
+    assert_equal @worker, $CAPTURED_WORKER
+  end
+
   if !defined?(RUBY_ENGINE) || defined?(RUBY_ENGINE) && RUBY_ENGINE != "jruby"
     [SignalException, Resque::TermException].each do |exception|
       {