Expire stale queued jobs on lock timeout expiration

Gemfile

@@ -5,4 +5,5 @@ gem "resque"
 group :development do
   gem "turn"
   gem "rake"
+  gem 'json'
 end

Rakefile

@@ -1,5 +1,4 @@
 require 'rake/testtask'
-require 'rake/rdoctask'
 
 def command?(command)
   system("type #{command} > /dev/null")

lib/resque/plugins/lock.rb

@@ -70,8 +70,9 @@ def before_enqueue_lock(*args)
         # (we cannot acquire the lock during the timeout period)
         return false if now <= Resque.redis.get(key).to_i
 
-        # otherwise set the timeout and ensure that no other worker has
-        # acquired the lock
+        # otherwise dequeue the job holding the current lock and reset the
+        # timeout to ensure that no other worker has acquired the lock
+        Resque.dequeue(self, *args)
         now > Resque.redis.getset(key, timeout).to_i
       end
 
@@ -84,6 +85,11 @@ def around_perform_lock(*args)
           Resque.redis.del(lock(*args))
         end
       end
+
+      # Some errors may not be capture by above `ensure'. Handle it here.
+      def on_failure_lock(exception, *args)
+        Resque.redis.del(lock(*args))
+      end
     end
   end
 end

resque-lock.gemspec

@@ -1,6 +1,6 @@
 Gem::Specification.new do |s|
   s.name              = "resque-lock"
-  s.version           = "1.1.0"
+  s.version           = "1.1.3"
   s.date              = Time.now.strftime('%Y-%m-%d')
   s.summary           = "A Resque plugin for ensuring only one instance of your job is queued at a time."
   s.homepage          = "http://github.com/defunkt/resque-lock"

test/lock_test.rb

@@ -55,6 +55,6 @@ def test_deadlock
 
     sleep 3
     Resque.enqueue(Job)
-    assert_equal 2, Resque.redis.llen('queue:lock_test')
+    assert_equal 1, Resque.redis.llen('queue:lock_test')
   end
 end