compensate for lack of ordered hash in ruby 1.8

Author: hone

lib/resque/multi_queue.rb

@@ -14,13 +14,14 @@ class MultiQueue
     def initialize(queues, redis)
       super()
 
-      @queues = {}
-      @redis  = redis
+      @queues     = queues # since ruby 1.8 doesn't have Ordered Hashes
+      @queue_hash = {}
+      @redis      = redis
 
       queues.each do |queue|
         key = @redis.is_a?(Redis::Namespace) ? "#{@redis.namespace}:" : ""
         key += queue.redis_name
-        @queues[key] = queue
+        @queue_hash[key] = queue
       end
     end
 
@@ -34,7 +35,7 @@ def pop(non_block = false)
         synchronize do
           value = nil
 
-          @queues.values.each do |queue|
+          @queues.each do |queue|
             begin
               return [queue, queue.pop(true)]
             rescue ThreadError
@@ -44,11 +45,11 @@ def pop(non_block = false)
           raise ThreadError
         end
       else
-        queue_names = @queues.values.map {|queue| queue.redis_name }
+        queue_names = @queues.map {|queue| queue.redis_name }
         synchronize do
           value = @redis.blpop(*(queue_names + [1])) until value
           queue_name, payload = value
-          queue = @queues[queue_name]
+          queue = @queue_hash[queue_name]
           [queue, queue.decode(payload)]
         end
       end

test/multi_queue_test.rb

@@ -49,4 +49,40 @@
       Timeout::timeout(2) { queue.pop }
     end
   end
+
+  it "blocking pop processes queues in the order given" do
+    foo    = Resque::Queue.new 'foo', redis, coder
+    bar    = Resque::Queue.new 'bar', redis, coder
+    baz    = Resque::Queue.new 'baz', redis, coder
+    queues = [foo, bar, baz]
+    queue  = Resque::MultiQueue.new(queues, redis)
+    job    = { 'class' => 'GoodJob', 'args' => [35, 'tar'] }
+
+    queues.each {|q| q << job }
+
+    processed_queues = queues.map do
+      q, j = queue.pop
+      q
+    end
+
+    assert_equal processed_queues, queues
+  end
+
+  it "nonblocking pop processes queues in the order given" do
+    foo    = Resque::Queue.new 'foo', redis, coder
+    bar    = Resque::Queue.new 'bar', redis, coder
+    baz    = Resque::Queue.new 'baz', redis, coder
+    queues = [foo, bar, baz]
+    queue  = Resque::MultiQueue.new(queues, redis)
+    job    = { 'class' => 'GoodJob', 'args' => [35, 'tar'] }
+
+    queues.each {|q| q << job }
+
+    processed_queues = queues.map do
+      q, j = queue.pop(true)
+      q
+    end
+
+    assert_equal processed_queues, queues
+  end
 end