Add middleware to restart the clock if necessary.

lib/sidetiq.rb

@@ -1,11 +1,11 @@
 # stdlib
-require 'singleton'
 require 'monitor'
 require 'ostruct'
+require 'singleton'
 
 # gems
-require 'sidekiq'
 require 'ice_cube'
+require 'sidekiq'
 
 # c extensions
 require 'sidetiq_ext'
@@ -13,6 +13,7 @@ require 'sidetiq_ext'
 # internal
 require 'sidetiq/config'
 require 'sidetiq/clock'
+require 'sidetiq/middleware'
 require 'sidetiq/schedule'
 require 'sidetiq/schedulable'
 require 'sidetiq/version'

lib/sidetiq/middleware.rb

@@ -0,0 +1,20 @@
+module Sidetiq
+  class Middleware
+    def initialize
+      @clock = Sidetiq::Clock.instance
+    end
+
+    def call(*args)
+      # Restart the clock if the thread died.
+      @clock.start! if !@clock.ticking?
+      yield
+    end
+  end
+end
+
+Sidekiq.configure_server do |config|
+  config.server_middleware do |chain|
+    chain.add Sidetiq::Middleware
+  end
+end
+

test/test_middleware.rb

@@ -0,0 +1,18 @@
+require_relative 'helper'
+
+class TestMiddleware < Sidetiq::TestCase
+  def middleware
+    Sidetiq::Middleware.new
+  end
+
+  def test_restarts_clock
+    clock.stubs(:ticking?).returns(false)
+    clock.expects(:start!).once
+    middleware.call {}
+
+    clock.stubs(:ticking?).returns(true)
+    clock.expects(:start!).never
+    middleware.call {}
+  end
+end
+