channel pools

lib/qusion.rb

@@ -5,6 +5,10 @@
 
 require QUSION_ROOT + "qusion/em"
 require QUSION_ROOT + "qusion/amqp"
+require QUSION_ROOT + "qusion/channel_pool"
 
 module Qusion
+  def self.channel
+    ChannelPool.instance.channel
+  end
 end

lib/qusion/channel_pool.rb

@@ -0,0 +1,44 @@
+# encoding: UTF-8
+require "singleton"
+
+module Qusion
+  class ChannelPool
+    include Singleton
+
+    class << self
+      attr_writer :pool_size
+
+      def pool_size
+        @pool_size || 5
+      end
+
+      def reset
+        @pool_size = nil
+        instance.reset
+      end
+
+    end
+
+    def channel
+      channel = @pool.shift
+      @pool << channel
+      channel
+    end
+
+    def pool
+      @pool ||= initialize_pool
+    end
+
+    def initialize_pool
+      @pool = []
+      self.class.pool_size.times do
+        @pool << MQ.new
+      end
+    end
+
+    def reset
+      @pool = nil
+    end
+
+  end
+end

spec/unit/channel_pool_spec.rb

@@ -0,0 +1,48 @@
+# encoding: UTF-8
+require File.dirname(__FILE__) + "/../spec_helper"
+
+describe ChannelPool do
+  MQ = Object.new
+
+  before(:each) do
+    ChannelPool.reset
+  end
+
+  it "should be singleton" do
+    lambda { ChannelPool.new }.should raise_error
+  end
+
+  it "should adjust the pool size" do
+    ChannelPool.pool_size = 5
+    ChannelPool.pool_size.should == 5
+  end
+
+  it "should create a pool of AMQP channels" do
+    ChannelPool.pool_size = 3
+    MQ.should_receive(:new).exactly(3).times
+    ChannelPool.instance.pool
+  end
+
+  it "should default to a pool size of 5" do
+    MQ.should_receive(:new).exactly(5).times
+    ChannelPool.instance.pool
+  end
+
+  it "should return a channel in a round-robin" do
+    ChannelPool.instance.instance_variable_set(:@pool, [1,2,3,4,5])
+    [1,2,3,4,5,1,2,3,4,5].each do |i|
+      ChannelPool.instance.channel.should == i
+    end
+
+  end
+
+end
+
+describe Qusion do
+  it "should provide a convenience method to get a channel from the pool" do
+    channel_pool = mock("channel pool")
+    ChannelPool.should_receive(:instance).and_return(channel_pool)
+    channel_pool.should_receive(:channel)
+    Qusion.channel
+  end
+end