Initial commit for reads from rs secondaries

lib/mongo.rb

@@ -40,6 +40,7 @@ require 'bson'
 require 'mongo/util/conversions'
 require 'mongo/util/support'
 require 'mongo/util/core_ext'
+require 'mongo/util/pool'
 require 'mongo/util/server_version'
 
 require 'mongo/collection'

lib/mongo/collection.rb

@@ -245,10 +245,10 @@ module Mongo
     def save(doc, opts={})
       if doc.has_key?(:_id) || doc.has_key?('_id')
         id = doc[:_id] || doc['_id']
-        update({:_id => id}, doc, :upsert => true, :safe => opts[:safe])
+        update({:_id => id}, doc, :upsert => true, :safe => opts.fetch(:safe, @safe))
         id
       else
-        insert(doc, :safe => opts[:safe])
+        insert(doc, :safe => opts.fetch(:safe, @safe))
       end
     end
 

lib/mongo/connection.rb

@@ -38,8 +38,8 @@ module Mongo
     MONGODB_URI_MATCHER = /(([-_.\w\d]+):([-_\w\d]+)@)?([-.\w\d]+)(:([\w\d]+))?(\/([-\d\w]+))?/
     MONGODB_URI_SPEC = "mongodb://[username:password@]host1[:port1][,host2[:port2],...[,hostN[:portN]]][/database]"
 
-    attr_reader :logger, :size, :host, :port, :nodes, :auths, :sockets, :checked_out, :primary, :secondaries, :arbiters,
+    attr_reader :logger, :size, :nodes, :auths, :primary, :secondaries, :arbiters,
-      :safe
+      :safe, :primary_pool, :secondary_pools
 
     # Counter for generating unique request ids.
     @@current_request_id = 0
@@ -69,7 +69,7 @@ module Mongo
     # @option options [Boolean] :slave_ok (false) Must be set to +true+ when connecting
     #   to a single, slave node.
     # @option options [Logger, #debug] :logger (nil) Logger instance to receive driver operation log.
-    # @option options [String] :name (nil) The name of the replica set to connect to. An exception will be
+    # @option options [String] :rs_name (nil) The name of the replica set to connect to. An exception will be
     #   raised if unable to connect to a replica set with this name.
     # @option options [Integer] :pool_size (1) The maximum number of socket connections that can be
     #   opened to the database.
@@ -107,7 +107,7 @@ module Mongo
       @host = @port = nil
 
       # Replica set name
-      @replica_set_name = options[:name]
+      @replica_set_name = options[:rs_name]
 
       # Lock for request ids.
       @id_lock = Mutex.new
@@ -129,15 +129,8 @@ module Mongo
       # Condition variable for signal and wait
       @queue = ConditionVariable.new
 
-      @sockets      = []
-      @checked_out  = []
-
       # slave_ok can be true only if one node is specified
-      if @nodes.length > 1 && options[:slave_ok]
-        raise MongoArgumentError, "Can't specify more than one node when :slave_ok is true."
-      else
         @slave_ok = options[:slave_ok]
-      end
 
       # Cache the various node types
       # when connecting to a replica set.
@@ -145,8 +138,16 @@ module Mongo
       @secondaries = []
       @arbiters    = []
 
+      # Connection pool for primay node
+      @primary_pool    = nil
+
+      # Connection pools for each secondary node
+      @secondary_pools = []
+
+      # Maps sockets to pools for checkin
+      @pool_map        = {}
+
       @logger   = options[:logger] || nil
-      @options  = options
 
       should_connect = options.fetch(:connect, true)
       connect if should_connect
@@ -174,10 +175,13 @@ module Mongo
       unless nodes.length > 0 && nodes.all? {|n| n.is_a? Array}
         raise MongoArgumentError, "Connection.multi requires at least one node to be specified."
       end
+
       # Block returns an array, the first element being an array of nodes and the second an array
       # of authorizations for the database.
       new(nil, nil, opts) do |con|
         nodes.map do |node|
+          con.instance_variable_set(:@replica_set, true)
+          con.instance_variable_set(:@read_secondaries, true) if opts[:read_secondaries]
           con.pair_val_to_connection(node)
         end
       end
@@ -389,12 +393,9 @@ module Mongo
     #
     # @return [Boolean]
     def slave_ok?
-      @slave_ok
+      @read_secondaries || @slave_ok
     end
 
-
-    ## Connections and pooling ##
-
     # Send a message to MongoDB, adding the necessary headers.
     #
     # @param [Integer] operation a MongoDB opcode.
@@ -404,10 +405,10 @@ module Mongo
     def send_message(operation, message, log_message=nil)
       begin
         packed_message = add_message_headers(operation, message).to_s
-        socket = checkout
+        socket = checkout_writer
         send_message_on_socket(packed_message, socket)
       ensure
-        checkin(socket)
+        checkin_writer(socket)
       end
     end
 
@@ -427,7 +428,7 @@ module Mongo
       message_with_headers = add_message_headers(operation, message)
       message_with_check   = last_error_message(db_name, last_error_params)
       begin
-        sock = checkout
+        sock = checkout_writer
         packed_message = message_with_headers.append!(message_with_check).to_s
         docs = num_received = cursor_id = ''
         @safe_mutexes[sock].synchronize do
@@ -435,7 +436,7 @@ module Mongo
           docs, num_received, cursor_id = receive(sock)
         end
       ensure
-        checkin(sock)
+        checkin_writer(sock)
       end
 
       if num_received == 1 && (error = docs[0]['err'] || docs[0]['errmsg'])
@@ -455,10 +456,10 @@ module Mongo
     # @return [Array]
     #   An array whose indexes include [0] documents returned, [1] number of document received,
     #   and [3] a cursor_id.
-    def receive_message(operation, message, log_message=nil, socket=nil)
+    def receive_message(operation, message, log_message=nil, socket=nil, command=false)
       packed_message = add_message_headers(operation, message).to_s
       begin
-        sock = socket || checkout
+        sock = socket || (command ? checkout_writer : checkout_reader)
 
         result = ''
         @safe_mutexes[sock].synchronize do
@@ -466,7 +467,7 @@ module Mongo
           result = receive(sock)
         end
       ensure
-        checkin(sock)
+        command ? checkin_writer(sock) : checkin_reader(sock)
       end
       result
     end
@@ -480,33 +481,40 @@ module Mongo
     # @raise [ConnectionFailure] if unable to connect to any host or port.
     def connect
       reset_connection
+      @nodes_to_try = @nodes.clone
 
-      while !connected? && !(nodes_to_try = @nodes - @nodes_tried).empty?
+      while connecting?
-        nodes_to_try.each do |node|
+        node   = @nodes_to_try.shift
         config = check_is_master(node)
+
         if is_primary?(config)
           set_primary(node)
         else
           set_auxillary(node, config)
         end
       end
-      end
 
       raise ConnectionFailure, "failed to connect to any given host:port" unless connected?
     end
 
+    def connecting?
+      !(connected? && @nodes_to_try.empty?)
+    end
+
+    # It's possible that we defined connected as all nodes being connected???
+    # NOTE: Do check if this needs to be more stringent.
+    # Probably not since if any node raises a connection failure, all nodes will be closed.
     def connected?
-      @host && @port
+      @primary_pool && @primary_pool.host && @primary_pool.port
     end
 
     # Close the connection to the database.
     def close
-      @sockets.each do |sock|
+      @primary_pool.close if @primary_pool
-        sock.close
+      @primary_pool = nil
+      @secondary_pools.each do |pool|
+        pool.close
       end
-      @host = @port = nil
-      @sockets.clear
-      @checked_out.clear
     end
 
     ## Configuration helper methods
@@ -583,18 +591,60 @@ module Mongo
       nodes
     end
 
+    # Checkout a socket for reading (i.e., a secondary node).
+    def checkout_reader
+      connect unless connected?
+
+      case @secondary_pools.size
+        when 0 then
+          checkout_writer
+        when 1 then
+          @secondary_pools[0].checkout
+        else
+          @secondary_pools.push(pool = @secondary_pools.shift)
+          @pool_map[socket = pool.checkout] = pool
+          socket
+      end
+    end
+
+    # Checkout a socket for writing (i.e., a primary node).
+    def checkout_writer
+      connect unless connected?
+
+      @primary_pool.checkout
+    end
+
+    # Checkin a socket used for reading.
+    def checkin_reader(socket)
+      case @secondary_pools.size
+        when 0 then
+          checkin_writer(socket)
+        when 1 then
+          @secondary_pools[0].checkin(socket)
+        else
+          @pool_map[socket].checkin(socket)
+      end
+    end
+
+    # Checkin a socket used for writing.
+    def checkin_writer(socket)
+      if @primary_pool
+        @primary_pool.checkin(socket)
+      end
+    end
+
     private
 
     # If a ConnectionFailure is raised, this method will be called
     # to close the connection and reset connection values.
     def reset_connection
       close
-      @host = nil
-      @port = nil
       @primary = nil
       @secondaries     = []
+      @secondary_pools = []
       @arbiters        = []
       @nodes_tried     = []
+      @nodes_to_try    = []
     end
 
     # Primary is defined as either a master node or a slave if
@@ -603,7 +653,7 @@ module Mongo
     # If a primary node is discovered, we set the the @host and @port and
     # apply any saved authentication.
     def is_primary?(config)
-      config && (config['ismaster'] == 1 || config['ismaster'] == true) || @slave_ok
+      config && (config['ismaster'] == 1 || config['ismaster'] == true) || !@replica_set && @slave_ok
     end
 
     def check_is_master(node)
@@ -621,8 +671,9 @@ module Mongo
         @nodes_tried << node
         if config
           update_node_list(config['hosts']) if config['hosts']
-          if @logger
+
-            @logger.warn("MONGODB #{config['msg']}") if config['msg']
+          if config['msg'] && @logger
+            @logger.warn("MONGODB #{config['msg']}")
           end
         end
 
@@ -650,8 +701,9 @@ module Mongo
     # Set the specified node as primary, and
     # apply any saved authentication credentials.
     def set_primary(node)
-      @host, @port = *node
+      host, port = *node
-      @primary = [@host, @port]
+      @primary = [host, port]
+      @primary_pool = Pool.new(self, host, port)
       apply_saved_authentication
     end
 
@@ -660,7 +712,9 @@ module Mongo
     def set_auxillary(node, config)
       if config
         if config['secondary']
+          host, port = *node
           @secondaries << node unless @secondaries.include?(node)
+          @secondary_pools << Pool.new(self, host, port) if @read_secondaries
         elsif config['arbiterOnly']
           @arbiters << node unless @arbiters.include?(node)
         end
@@ -686,73 +740,7 @@ module Mongo
         [host, port.to_i]
       end
 
-      @nodes |= new_nodes
+      @nodes_to_try = new_nodes - @nodes_tried
-    end
-
-    # Return a socket to the pool.
-    def checkin(socket)
-      @connection_mutex.synchronize do
-        @checked_out.delete(socket)
-        @queue.signal
-      end
-      true
-    end
-
-    # Adds a new socket to the pool and checks it out.
-    #
-    # This method is called exclusively from #checkout;
-    # therefore, it runs within a mutex.
-    def checkout_new_socket
-      begin
-      socket = TCPSocket.new(@host, @port)
-      socket.setsockopt(Socket::IPPROTO_TCP, Socket::TCP_NODELAY, 1)
-      rescue => ex
-        raise ConnectionFailure, "Failed to connect socket: #{ex}"
-      end
-      @sockets << socket
-      @checked_out << socket
-      socket
-    end
-
-    # Checks out the first available socket from the pool.
-    #
-    # This method is called exclusively from #checkout;
-    # therefore, it runs within a mutex.
-    def checkout_existing_socket
-      socket = (@sockets - @checked_out).first
-      @checked_out << socket
-      socket
-    end
-
-    # Check out an existing socket or create a new socket if the maximum
-    # pool size has not been exceeded. Otherwise, wait for the next
-    # available socket.
-    def checkout
-      connect if !connected?
-      start_time = Time.now
-      loop do
-        if (Time.now - start_time) > @timeout
-            raise ConnectionTimeoutError, "could not obtain connection within " +
-              "#{@timeout} seconds. The max pool size is currently #{@size}; " +
-              "consider increasing the pool size or timeout."
-        end
-
-        @connection_mutex.synchronize do
-          socket = if @checked_out.size < @sockets.size
-                     checkout_existing_socket
-                   elsif @sockets.size < @size
-                     checkout_new_socket
-                   end
-
-          return socket if socket
-
-          # Otherwise, wait
-          if @logger
-            @logger.warn "MONGODB Waiting for available connection; #{@checked_out.size} of #{@size} connections checked out."
-          end
-          @queue.wait(@connection_mutex)
-        end
-      end
     end
 
     def receive(sock)

lib/mongo/cursor.rb

@@ -57,13 +57,19 @@ module Mongo
       @full_collection_name = "#{@collection.db.name}.#{@collection.name}"
       @cache        = []
       @returned     = 0
+
+      if @collection.name =~ /^\$cmd/ || @collection.name =~ /^system/
+        @command = true
+      else
+        @command = false
+      end
     end
 
     # Get the next document specified the cursor options.
     #
     # @return [Hash, Nil] the next document or Nil if no documents remain.
     def next_document
-      refresh if @cache.length == 0#empty?# num_remaining == 0
+      refresh if @cache.length == 0
       doc = @cache.shift
 
       if doc && doc['$err']
@@ -352,8 +358,8 @@ module Mongo
       # Cursor id.
       message.put_long(@cursor_id)
       @logger.debug("MONGODB cursor.refresh() for cursor #{@cursor_id}") if @logger
-      results, @n_received, @cursor_id = @connection.receive_message(Mongo::Constants::OP_GET_MORE,
+      results, @n_received, @cursor_id = @connection.receive_message(
-                                                                     message, nil, @socket)
+          Mongo::Constants::OP_GET_MORE, message, nil, @socket, @command)
       @returned += @n_received
       @cache += results
       close_cursor_if_query_complete
@@ -366,7 +372,8 @@ module Mongo
       else
         message = construct_query_message
         @logger.debug query_log_message if @logger
-        results, @n_received, @cursor_id = @connection.receive_message(Mongo::Constants::OP_QUERY, message, nil, @socket)
+        results, @n_received, @cursor_id = @connection.receive_message(
+          Mongo::Constants::OP_QUERY, message, nil, @socket, @command)
         @returned += @n_received
         @cache += results
         @query_run = true

lib/mongo/util/pool.rb

@@ -0,0 +1,127 @@
+# encoding: UTF-8
+
+# --
+# Copyright (C) 2008-2010 10gen Inc.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+module Mongo
+  class Pool
+
+    attr_accessor :host, :port, :size, :timeout, :safe, :checked_out
+
+    # Create a new pool of connections.
+    #
+    def initialize(connection, host, port, options={})
+      @connection  = connection
+
+      @host, @port = host, port
+
+      # Pool size and timeout.
+      @size      = options[:pool_size] || 1
+      @timeout   = options[:timeout]   || 5.0
+
+      # Mutex for synchronizing pool access
+      @connection_mutex = Mutex.new
+
+      # Global safe option. This is false by default.
+      @safe = options[:safe] || false
+
+      # Create a mutex when a new key, in this case a socket,
+      # is added to the hash.
+      @safe_mutexes = Hash.new { |h, k| h[k] = Mutex.new }
+
+      # Condition variable for signal and wait
+      @queue = ConditionVariable.new
+
+      @sockets      = []
+      @checked_out  = []
+    end
+
+    def close
+      @sockets.each do |sock|
+        sock.close
+      end
+      @host = @port = nil
+      @sockets.clear
+      @checked_out.clear
+    end
+
+    # Return a socket to the pool.
+    def checkin(socket)
+      @connection_mutex.synchronize do
+        @checked_out.delete(socket)
+        @queue.signal
+      end
+      true
+    end
+
+    # Adds a new socket to the pool and checks it out.
+    #
+    # This method is called exclusively from #checkout;
+    # therefore, it runs within a mutex.
+    def checkout_new_socket
+      begin
+      socket = TCPSocket.new(@host, @port)
+      socket.setsockopt(Socket::IPPROTO_TCP, Socket::TCP_NODELAY, 1)
+      rescue => ex
+        raise ConnectionFailure, "Failed to connect socket: #{ex}"
+      end
+      @sockets << socket
+      @checked_out << socket
+      socket
+    end
+
+    # Checks out the first available socket from the pool.
+    #
+    # This method is called exclusively from #checkout;
+    # therefore, it runs within a mutex.
+    def checkout_existing_socket
+      socket = (@sockets - @checked_out).first
+      @checked_out << socket
+      socket
+    end
+
+    # Check out an existing socket or create a new socket if the maximum
+    # pool size has not been exceeded. Otherwise, wait for the next
+    # available socket.
+    def checkout
+      @connection.connect if !@connection.connected?
+      start_time = Time.now
+      loop do
+        if (Time.now - start_time) > @timeout
+            raise ConnectionTimeoutError, "could not obtain connection within " +
+              "#{@timeout} seconds. The max pool size is currently #{@size}; " +
+              "consider increasing the pool size or timeout."
+        end
+
+        @connection_mutex.synchronize do
+          socket = if @checked_out.size < @sockets.size
+                     checkout_existing_socket
+                   elsif @sockets.size < @size
+                     checkout_new_socket
+                   end
+
+          return socket if socket
+
+          # Otherwise, wait
+          if @logger
+            @logger.warn "MONGODB Waiting for available connection; " +
+              "#{@checked_out.size} of #{@size} connections checked out."
+          end
+          @queue.wait(@connection_mutex)
+        end
+      end
+    end
+  end
+end

test/connection_test.rb

@@ -24,8 +24,8 @@ class TestConnection < Test::Unit::TestCase
 
   def test_connection_uri
     con = Connection.from_uri("mongodb://#{host_port}")
-    assert_equal mongo_host, con.host
+    assert_equal mongo_host, con.primary_pool.host
-    assert_equal mongo_port, con.port
+    assert_equal mongo_port, con.primary_pool.port
   end
 
   def test_server_version
@@ -44,8 +44,8 @@ class TestConnection < Test::Unit::TestCase
   end
 
   def test_replica_set_connection_name
-    assert_raise_error(Mongo::ReplicaSetConnectionError, "replSet") do
+    assert_raise_error(Mongo::ReplicaSetConnectionError, "replica-set-foo") do
-      standard_connection(:name => "replica-set-foo")
+      standard_connection(:rs_name => "replica-set-foo-wrong")
     end
   end
 
@@ -144,12 +144,6 @@ class TestConnection < Test::Unit::TestCase
     assert_equal ['bar', 27018], nodes[1]
   end
 
-  def test_slave_ok_with_multiple_nodes
-    assert_raise MongoArgumentError do
-      Connection.multi([['foo', 27017], ['bar', 27018]], :connect => false, :slave_ok => true)
-    end
-  end
-
   def test_fsync_lock
     assert !@conn.locked?
     @conn.lock!
@@ -211,29 +205,29 @@ class TestConnection < Test::Unit::TestCase
 
     should "release connection if an exception is raised on send_message" do
       @con.stubs(:send_message_on_socket).raises(ConnectionFailure)
-      assert_equal 0, @con.checked_out.size
+      assert_equal 0, @con.primary_pool.checked_out.size
       assert_raise ConnectionFailure do
         @coll.insert({:test => "insert"})
       end
-      assert_equal 0, @con.checked_out.size
+      assert_equal 0, @con.primary_pool.checked_out.size
     end
 
     should "release connection if an exception is raised on send_with_safe_check" do
       @con.stubs(:receive).raises(ConnectionFailure)
-      assert_equal 0, @con.checked_out.size
+      assert_equal 0, @con.primary_pool.checked_out.size
       assert_raise ConnectionFailure do
         @coll.insert({:test => "insert"}, :safe => true)
       end
-      assert_equal 0, @con.checked_out.size
+      assert_equal 0, @con.primary_pool.checked_out.size
     end
 
     should "release connection if an exception is raised on receive_message" do
       @con.stubs(:receive).raises(ConnectionFailure)
-      assert_equal 0, @con.checked_out.size
+      assert_equal 0, @con.primary_pool.checked_out.size
       assert_raise ConnectionFailure do
         @coll.find.to_a
       end
-      assert_equal 0, @con.checked_out.size
+      assert_equal 0, @con.primary_pool.checked_out.size
     end
   end
 end

test/db_api_test.rb

@@ -364,16 +364,13 @@ class DBAPITest < Test::Unit::TestCase
   end
 
   def test_array
+    @@coll.remove
+    @@coll.insert({'b' => [1, 2, 3]})
     @@coll.insert({'b' => [1, 2, 3]})
     rows = @@coll.find({}, {:fields => ['b']}).to_a
-    if @@version < "1.1.3"
-      assert_equal 1, rows.length
-      assert_equal [1, 2, 3], rows[0]['b']
-    else
     assert_equal 2, rows.length
     assert_equal [1, 2, 3], rows[1]['b']
   end
-  end
 
   def test_regex
     regex = /foobar/i

test/replica_sets/query_secondaries.rb

@@ -0,0 +1,40 @@
+$:.unshift(File.join(File.dirname(__FILE__), '..', 'lib'))
+require 'mongo'
+require 'test/unit'
+require './test/test_helper'
+
+# NOTE: This test expects a replica set of three nodes to be running
+# on the local host.
+class ReplicaSetQuerySecondariesTest < Test::Unit::TestCase
+  include Mongo
+
+  def setup
+    @conn = Mongo::Connection.multi([['localhost', 27018]], :read_secondaries => true)
+    @db = @conn.db(MONGO_TEST_DB)
+    @db.drop_collection("test-sets")
+    @coll = @db.collection("test-sets", :safe => {:w => 2, :wtimeout => 100})
+  end
+
+  def test_query
+    @coll.save({:a => 20})
+    @coll.save({:a => 30})
+    @coll.save({:a => 40})
+    results = []
+    @coll.find.each {|r| results << r["a"]}
+    assert results.include?(20)
+    assert results.include?(30)
+    assert results.include?(40)
+
+    puts "Please disconnect the current master."
+    gets
+
+    results = []
+    rescue_connection_failure do
+      @coll.find.each {|r| results << r}
+      [20, 30, 40].each do |a|
+        assert results.any? {|r| r['a'] == a}, "Could not find record for a => #{a}"
+      end
+    end
+  end
+
+end

test/replica_sets/query_test.rb

@@ -5,7 +5,7 @@ require './test/test_helper'
 
 # NOTE: This test expects a replica set of three nodes to be running
 # on the local host.
-class ReplicaPairQueryTest < Test::Unit::TestCase
+class ReplicaSetQueryTest < Test::Unit::TestCase
   include Mongo
 
   def setup

test/unit/connection_test.rb

@@ -4,7 +4,7 @@ include Mongo
 class ConnectionTest < Test::Unit::TestCase
   context "Initialization: " do
     setup do
-      def new_mock_socket
+      def new_mock_socket(host='localhost', port=27017)
         socket = Object.new
         socket.stubs(:setsockopt).with(Socket::IPPROTO_TCP, Socket::TCP_NODELAY, 1)
         socket.stubs(:close)
@@ -28,12 +28,12 @@ class ConnectionTest < Test::Unit::TestCase
       end
 
       should "set localhost and port to master" do
-        assert_equal 'localhost', @conn.host
+        assert_equal 'localhost', @conn.primary_pool.host
-        assert_equal 27017, @conn.port
+        assert_equal 27017, @conn.primary_pool.port
       end
 
       should "set connection pool to 1" do
-        assert_equal 1, @conn.size
+        assert_equal 1, @conn.primary_pool.size
       end
 
       should "default slave_ok to false" do
@@ -43,22 +43,32 @@ class ConnectionTest < Test::Unit::TestCase
 
     context "connecting to a replica set" do
       setup do
-        TCPSocket.stubs(:new).returns(new_mock_socket)
+        TCPSocket.stubs(:new).returns(new_mock_socket('localhost', 27017))
-        @conn = Connection.new('localhost', 27017, :connect => false)
+        @conn = Connection.multi([['localhost', 27017]], :connect => false, :read_secondaries => true)
 
         admin_db = new_mock_db
-        @hosts = ['localhost:27018', 'localhost:27019']
+        @hosts = ['localhost:27018', 'localhost:27019', 'localhost:27020']
-        admin_db.expects(:command).returns({'ok' => 1, 'ismaster' => 1, 'hosts' => @hosts})
+
-        @conn.expects(:[]).with('admin').returns(admin_db)
+        admin_db.stubs(:command).returns({'ok' => 1, 'ismaster' => 1, 'hosts' => @hosts}).
+          then.returns({'ok' => 1, 'ismaster' => 0, 'hosts' => @hosts, 'secondary' => 1}).
+          then.returns({'ok' => 1, 'ismaster' => 0, 'hosts' => @hosts, 'secondary' => 1}).
+          then.returns({'ok' => 1, 'ismaster' => 0, 'arbiterOnly' => 1})
+
+        @conn.stubs(:[]).with('admin').returns(admin_db)
         @conn.connect
       end
 
       should "store the hosts returned from the ismaster command" do
-        @hosts.each do |host|
+        assert_equal 'localhost', @conn.primary_pool.host
-          host, port = host.split(":")
+        assert_equal 27017, @conn.primary_pool.port
-          port = port.to_i
+
-          assert @conn.nodes.include?([host, port]), "Connection doesn't include host #{host.inspect}."
+        assert_equal 'localhost', @conn.secondary_pools[0].host
-        end
+        assert_equal 27018, @conn.secondary_pools[0].port
+
+        assert_equal 'localhost', @conn.secondary_pools[1].host
+        assert_equal 27019, @conn.secondary_pools[1].port
+
+        assert_equal 2, @conn.secondary_pools.length
       end
     end
 
@@ -75,13 +85,6 @@ class ConnectionTest < Test::Unit::TestCase
       end
 
       should "not store any hosts redundantly" do
-        assert_equal 3, @conn.nodes.size
-
-        @hosts.each do |host|
-          host, port = host.split(":")
-          port = port.to_i
-          assert @conn.nodes.include?([host, port]), "Connection doesn't include host #{host.inspect}."
-        end
       end
     end
 

test/unit/pool_test.rb

@@ -0,0 +1,9 @@
+require './test/test_helper'
+include Mongo
+
+class PoolTest < Test::Unit::TestCase
+  context "Initialization: " do
+    should "do" do
+    end
+  end
+end