RUBY-406 added ReplSetConnection read preference :secondary_only

lib/mongo/repl_set_connection.rb

@@ -224,7 +224,6 @@ module Mongo
       @manager = background_manager
       old_manager.close(:soft => true)
       @refresh_version += 1
-
       return true
     end
 
@@ -324,11 +323,9 @@ module Mongo
       else
         connect
       end
-
       begin
         socket = get_socket_from_pool(self.read_pool)
-
-        if !socket
+        if !socket && @read != :secondary_only
           connect
           socket = get_socket_from_pool(self.primary_pool)
         end

lib/mongo/util/pool_manager.rb

@@ -232,7 +232,7 @@ module Mongo
     # If more than one node is available, use the ping
     # time to figure out which nodes to choose from.
     def set_read_pool
-      if @secondary_pools.empty?
+      if @secondary_pools.empty? && @connection.read_preference != :secondary_only
          @read_pool = @primary_pool
       elsif @secondary_pools.size == 1
          @read_pool = @secondary_pools[0]

lib/mongo/util/support.rb

@@ -59,11 +59,11 @@ module Mongo
     end
 
     def validate_read_preference(value)
-      if [:primary, :secondary, nil].include?(value)
+      if [:primary, :secondary, :secondary_only, nil].include?(value)
         return true
       else
         raise MongoArgumentError, "#{value} is not a valid read preference. " +
-          "Please specify either :primary or :secondary."
+          "Please specify either :primary or :secondary or :secondary_only."
       end
     end
 

test/replica_sets/read_preference_test.rb

@@ -13,7 +13,6 @@ class ReadPreferenceTest < Test::Unit::TestCase
           :refresh_mode => false, :refresh_interval => 5, :logger => log)
     @db = @conn.db(MONGO_TEST_DB)
     @db.drop_collection("test-sets")
-    col = @db['mongo-test']
   end
 
   def teardown
@@ -34,6 +33,20 @@ class ReadPreferenceTest < Test::Unit::TestCase
       "Primary port and read port at the same!"
   end
 
+  def test_read_secondary_only
+    @conn = ReplSetConnection.new([@rs.host, @rs.ports[0]], [@rs.host, @rs.ports[1]], :read => :secondary_only)
+    assert_equal @conn.read_preference, :secondary_only
+    
+    @db = @conn.db(MONGO_TEST_DB)
+    @coll = @db.collection("test-sets")
+    @coll.save({:a => 20})
+    @rs.kill_all_secondaries
+    
+    assert_raise ConnectionFailure do
+      @coll.find_one
+    end
+  end
+
   def test_query_secondaries
     @secondary = Connection.new(@rs.host, @conn.read_pool.port, :slave_ok => true)
     @coll = @db.collection("test-sets", :safe => {:w => 3, :wtimeout => 20000})