Pre-bind sockets on creation

When sending a datagram, non-bound sockets require a DNS lookup.
Instead, bind the socket to the given addresses when creating the
socket.

Also, lazily create the socket connections, which allows the
notify methods to capture the exceptions as expected.  If the sockets
are created and bound at initialize, an exception would occur then.

Lastly, allow resetting the connections if the addresses are changed.

Fixes graylog-labs#31

lib/gelf/ruby_sender.rb

@@ -4,21 +4,44 @@ class RubyUdpSender
     attr_accessor :addresses
 
     def initialize(addresses)
-      @addresses = addresses
+      self.addresses = addresses
       @i = 0
-      @socket = UDPSocket.open
     end
 
     def send_datagrams(datagrams)
-      host, port = @addresses[@i]
+      # Choose next round robin socket to use to send all datagrams
+      socket = sockets[@i]
       @i = (@i + 1) % @addresses.length
+
       datagrams.each do |datagram|
-        @socket.send(datagram, 0, host, port)
+        socket.send(datagram, 0)
       end
     end
 
     def close
-      @socket.close
+      @sockets.each(&:close) if @sockets
+      @sockets = nil
+    end
+
+    # Set new addresses for the sender
+    def addresses=(addresses)
+      # Close any previously bound sockets
+      close
+
+      @addresses = addresses
+    end
+
+    private
+
+    # Get UDPSockets that are prebound to the given addresses
+    def sockets
+      @sockets ||= addresses.map do |address|
+        host, port = address
+
+        socket = UDPSocket.new
+        socket.connect(host, port)
+        socket
+      end
     end
   end
 end

test/test_ruby_sender.rb

@@ -10,18 +10,65 @@ class TestRubyUdpSender < Test::Unit::TestCase
     end
 
     context "send_datagrams" do
-      setup do
+      before_should "be called 3 times with 1st and 2nd datagrams" do
+        sockets = [mock, mock]
+
+        @sender.instance_variable_set('@sockets', sockets)
+
+        sockets[0].expects(:send).times(3).with do |datagram, _|
+          datagram.start_with?('d')
+        end
+        sockets[1].expects(:send).times(3).with do |datagram, _|
+          datagram.start_with?('e')
+        end
+
         @sender.send_datagrams(@datagrams1)
         @sender.send_datagrams(@datagrams2)
       end
 
-      before_should "be called 3 times with 1st and 2nd address" do
-        UDPSocket.any_instance.expects(:send).times(3).with do |datagram, _, host, port|
-          datagram.start_with?('d') && host == 'localhost' && port == 12201
-        end
-        UDPSocket.any_instance.expects(:send).times(3).with do |datagram, _, host, port|
-          datagram.start_with?('e') && host == 'localhost' && port == 12202
-        end
+      should "set the proper hostname and ports" do
+        sockets = @sender.send(:sockets)
+
+        assert_equal ['localhost', '12201'], sockets[0].remote_address.getnameinfo
+        assert_equal ['localhost', '12202'], sockets[1].remote_address.getnameinfo
+      end
+    end
+
+    context "close" do
+      should "close all open sockets" do
+        sockets = @sender.send(:sockets)
+
+        sockets[0].expects(:close)
+        sockets[1].expects(:close)
+
+        @sender.close
+      end
+
+      should "not fail if no sockets open" do
+        @sender.close
+      end
+
+      should 'reset sockets' do
+        original_sockets = @sender.send(:sockets)
+
+        # Sanity check that sockets method returns same socket connections
+        assert_equal original_sockets, @sender.send(:sockets)
+        @sender.close
+
+        # Check that sockets returns new sockets
+        assert_not_equal original_sockets, @sender.send(:sockets)
+      end
+    end
+
+    context "addresses=" do
+      should "close old connections" do
+        @sender.expects(:close)
+        @sender.addresses = ['localhost', 12201]
+      end
+
+      should "set new addresses" do
+        @sender.addresses = [['localhost', 12201]]
+        assert_equal [['localhost', 12201]], @sender.addresses
       end
     end
   end