Avoid calling processor during hard shutdown, fixes #997

Changes.md

@@ -3,6 +3,7 @@
 
 - Revert back to Celluloid's TaskFiber for job processing which has proven to be more
   stable than TaskThread. [#985]
+- Avoid possible lockup during hard shutdown [#997]
 
 At this point, if you are experiencing stability issues with Sidekiq in
 Ruby 1.9, please try Ruby 2.0.  It seems to be more stable.

lib/sidekiq/manager.rb

@@ -25,10 +25,11 @@ module Sidekiq
       @done_callback = nil
 
       @in_progress = {}
+      @threads = {}
       @done = false
       @busy = []
       @fetcher = Fetcher.new(current_actor, options)
-      @ready = @count.times.map { Processor.new_link(current_actor) }
+      @ready = @count.times.map { Processor.new_link(current_actor).tap {|p| p.proxy_id = p.object_id} }
     end
 
     def stop(options={})
@@ -63,6 +64,7 @@ module Sidekiq
       watchdog('Manager#processor_done died') do
         @done_callback.call(processor) if @done_callback
         @in_progress.delete(processor.object_id)
+        @threads.delete(processor.object_id)
         @busy.delete(processor)
         if stopped?
           processor.terminate if processor.alive?
@@ -77,10 +79,13 @@ module Sidekiq
     def processor_died(processor, reason)
       watchdog("Manager#processor_died died") do
         @in_progress.delete(processor.object_id)
+        @threads.delete(processor.object_id)
         @busy.delete(processor)
 
         unless stopped?
-          @ready << Processor.new_link(current_actor)
+          @ready << Processor.new_link(current_actor).tap do |p|
+            p.proxy_id = p.object_id
+          end
           dispatch
         else
           signal(:shutdown) if @busy.empty?
@@ -105,6 +110,14 @@ module Sidekiq
       end
     end
 
+    # A hack worthy of Rube Goldberg.  We need to be able
+    # to hard stop a working thread.  But there's no way for us to
+    # get handle to the underlying thread performing work for a processor
+    # so we have it call us and tell us.
+    def real_thread(proxy_id, thr)
+      @threads[proxy_id] = thr
+    end
+
     def procline(tag)
       "sidekiq #{Sidekiq::VERSION} #{tag}[#{@busy.size} of #{@count} busy]#{stopped? ? ' stopping' : ''}"
     end
@@ -145,10 +158,9 @@ module Sidekiq
           # it is worse to lose a job than to run it twice.
           Sidekiq::Fetcher.strategy.bulk_requeue(@in_progress.values)
 
-          logger.debug { "Terminating worker threads" }
+          logger.debug { "Terminating #{@busy.size} busy worker threads" }
           @busy.each do |processor|
-            if processor.alive?
-              t = processor.bare_object.actual_work_thread
+            if processor.alive? && t = @threads.delete(processor.object_id)
               t.raise Shutdown
             end
           end

lib/sidekiq/middleware/server/retry_jobs.rb

@@ -43,13 +43,12 @@ module Sidekiq
       class RetryJobs
         include Sidekiq::Util
 
-        # delayed_job uses the same basic formula
         DEFAULT_MAX_RETRY_ATTEMPTS = 25
 
         def call(worker, msg, queue)
           yield
         rescue Sidekiq::Shutdown
-          # ignore, will be pushed back onto queue
+          # ignore, will be pushed back onto queue during hard_shutdown
           raise
         rescue Exception => e
           raise e unless msg['retry']
@@ -110,6 +109,7 @@ module Sidekiq
           end
         end
 
+        # delayed_job uses the same basic formula
         def seconds_to_delay(count)
           (count ** 4) + 15 + (rand(30)*(count+1))
         end

lib/sidekiq/processor.rb

@@ -24,10 +24,7 @@ module Sidekiq
       end
     end
 
-    # store the actual working thread so we
-    # can later kill if it necessary during
-    # hard shutdown.
-    attr_accessor :actual_work_thread
+    attr_accessor :proxy_id
 
     def initialize(boss)
       @boss = boss
@@ -37,8 +34,9 @@ module Sidekiq
       msgstr = work.message
       queue = work.queue_name
 
-      @actual_work_thread = Thread.current
       do_defer do
+        @boss.async.real_thread(proxy_id, Thread.current)
+
         begin
           msg = Sidekiq.load_json(msgstr)
           klass  = msg['class'].constantize

myapp/app/controllers/work_controller.rb

@@ -20,7 +20,7 @@ class WorkController < ApplicationController
 
   def long
     50.times do |x|
-      HardWorker.perform_async('bob', 10, x)
+      HardWorker.perform_async('bob', 15, x)
     end
     render :text => 'enqueued'
   end

test/test_middleware.rb

@@ -82,6 +82,8 @@ class TestMiddleware < Minitest::Test
       processor = Sidekiq::Processor.new(boss)
       actor = Minitest::Mock.new
       actor.expect(:processor_done, nil, [processor])
+      actor.expect(:real_thread, nil, [nil, Celluloid::Thread])
+      boss.expect(:async, actor, [])
       boss.expect(:async, actor, [])
       processor.process(Sidekiq::BasicFetch::UnitOfWork.new('queue:default', msg))
       assert_equal %w(2 before 3 before 0 before work_performed 0 after 3 after 2 after), $recorder.flatten

test/test_processor.rb

@@ -31,6 +31,8 @@ class TestProcessor < Minitest::Test
       msg = Sidekiq.dump_json({ 'class' => MockWorker.to_s, 'args' => ['myarg'] })
       actor = Minitest::Mock.new
       actor.expect(:processor_done, nil, [@processor])
+      actor.expect(:real_thread, nil, [nil, Celluloid::Thread])
+      @boss.expect(:async, actor, [])
       @boss.expect(:async, actor, [])
       @processor.process(work(msg))
       @boss.verify
@@ -38,6 +40,9 @@ class TestProcessor < Minitest::Test
     end
 
     it 'passes exceptions to ExceptionHandler' do
+      actor = Minitest::Mock.new
+      actor.expect(:real_thread, nil, [nil, Celluloid::Thread])
+      @boss.expect(:async, actor, [])
       msg = Sidekiq.dump_json({ 'class' => MockWorker.to_s, 'args' => ['boom'] })
       begin
         @processor.process(work(msg))
@@ -51,6 +56,9 @@ class TestProcessor < Minitest::Test
     it 're-raises exceptions after handling' do
       msg = Sidekiq.dump_json({ 'class' => MockWorker.to_s, 'args' => ['boom'] })
       re_raise = false
+      actor = Minitest::Mock.new
+      actor.expect(:real_thread, nil, [nil, Celluloid::Thread])
+      @boss.expect(:async, actor, [])
 
       begin
         @processor.process(work(msg))
@@ -67,6 +75,8 @@ class TestProcessor < Minitest::Test
       processor = ::Sidekiq::Processor.new(@boss)
       actor = Minitest::Mock.new
       actor.expect(:processor_done, nil, [processor])
+      actor.expect(:real_thread, nil, [nil, Celluloid::Thread])
+      @boss.expect(:async, actor, [])
       @boss.expect(:async, actor, [])
       processor.process(work(msgstr))
       assert_equal [['myarg']], msg['args']
@@ -93,8 +103,10 @@ class TestProcessor < Minitest::Test
         def successful_job
           msg = Sidekiq.dump_json({ 'class' => MockWorker.to_s, 'args' => ['myarg'] })
           actor = Minitest::Mock.new
+          actor.expect(:real_thread, nil, [nil, Celluloid::Thread])
           actor.expect(:processor_done, nil, [@processor])
           @boss.expect(:async, actor, [])
+          @boss.expect(:async, actor, [])
           @processor.process(work(msg))
         end
 
@@ -118,6 +130,9 @@ class TestProcessor < Minitest::Test
         let(:failed_today_key) { "stat:failed:#{Time.now.utc.to_date}" }
 
         def failed_job
+          actor = Minitest::Mock.new
+          actor.expect(:real_thread, nil, [nil, Celluloid::Thread])
+          @boss.expect(:async, actor, [])
           msg = Sidekiq.dump_json({ 'class' => MockWorker.to_s, 'args' => ['boom'] })
           begin
             @processor.process(work(msg))