RUBY-367 deprecate async refresh

docs/REPLICA_SETS.md

@@ -44,19 +44,15 @@ be used for reads.
 Refresh mode is disabled by default.
 
 However, if you expect to make live changes to your secondaries, and you want this to be reflected without
-having to manually restart your app server, then you should enable it. You can enable synchronously, which will
-refresh the replica set data in a synchronous fashion (which may ocassionally slow down your queries):
+having to manually restart your app server, then you should enable it. You can enable this mode
+synchronously, which will refresh the replica set data in a synchronous fashion (which may
+ocassionally slow down your queries):
 
     @connection = ReplSetConnection.new(['n1.mydb.net', 27017], :refresh_mode => :sync)
 
-If you want to refresh via a background thread, use the `:async` mode. NOTE: the background
-version may be more effective on platforms that use native threads, such as JRuby:
-
-    @connection = ReplSetConnection.new(['n1.mydb.net', 27017], :refresh_mode => :async)
-
 If you want to change the default refresh interval of 90 seconds, you can do so like this:
 
-    @connection = ReplSetConnection.new(['n1.mydb.net', 27017], :refresh_mode => :async,
+    @connection = ReplSetConnection.new(['n1.mydb.net', 27017], :refresh_mode => :sync,
         :refresh_interval => 60)
 
 Do not set this value to anything lower than 30, or you may start to experience performance issues.

lib/mongo/repl_set_connection.rb

@@ -56,11 +56,10 @@ module Mongo
     # @option opts [Float] :connect_timeout (nil) The number of seconds to wait before timing out a
     #   connection attempt.
     # @option opts [Boolean] :ssl (false) If true, create the connection to the server using SSL.
-    # @option opts [Boolean] :refresh_mode (false) Set this to :async to enable a background thread that
-    #   periodically updates the state of the connection. If, for example, you initially connect while a secondary
-    #   is down, this will reconnect to that secondary behind the scenes to
-    #   prevent you from having to reconnect manually. If set to :sync, refresh will happen
-    #   synchronously. If +false+, no automatic refresh will occur unless there's a connection failure.
+    # @option opts [Boolean] :refresh_mode (false) Set this to :sync to periodically update the
+    #   state of the connection every :refresh_interval seconds. Replica set connection failures
+    #   will always trigger a complete refresh. This option is useful when you want to add new nodes
+    #   or remove replica set nodes not currently in use by the driver.
     # @option opts [Integer] :refresh_interval (90) If :refresh_mode is enabled, this is the number of seconds
     #   between calls to check the replica set's state.
     # @option opts [Boolean] :require_primary (true) If true, require a primary node for the connection
@@ -107,9 +106,12 @@ module Mongo
       @manager = nil
       @pool_mutex = Mutex.new
 
-      if ![:sync, :async, false].include?(@refresh_mode)
+      if @refresh_mode == :async
+        warn ":async refresh mode has been deprecated. Refresh
+        mode will be disabled."
+      elsif ![:sync, false].include?(@refresh_mode)
         raise MongoArgumentError,
-          "Refresh mode must be one of :sync, :async, or false."
+          "Refresh mode must be either :sync or false."
       end
 
       # Are we allowing reads from secondaries?
@@ -124,15 +126,8 @@ module Mongo
       end
 
       @connected = false
-
-      # Store the refresher thread
-      @refresh_thread  = nil
       @refresh_version = 0
 
-      # Maps
-      @threads_to_sockets = Hash.new { |h, k| h[k] = Hash.new }
-      @tag_map = nil
-
       # Replica set name
       if opts[:rs_name]
         warn ":rs_name option has been deprecated and will be removed in v2.0. " +
@@ -161,7 +156,6 @@ module Mongo
       manager.connect
 
       update_config(manager)
-      initiate_refresh_mode
 
       if @require_primary && self.primary.nil? #TODO: in v2.0, we'll let this be optional and do a lazy connect.
         close
@@ -213,7 +207,6 @@ module Mongo
       old_manager = @manager
       update_config(background_manager)
       old_manager.close(:soft => true)
-      initiate_refresh_mode
 
       return true
     end
@@ -265,7 +258,6 @@ module Mongo
     def close
       @connected = false
       @manager.close(:soft => true) if @manager
-      @threads_to_sockets.clear
     end
 
     # If a ConnectionFailure is raised, this method will be called
@@ -470,6 +462,8 @@ module Mongo
         write_logging_startup_message
       end
 
+      @last_refresh = Time.now
+
       should_connect = opts.fetch(:connect, true)
       connect if should_connect
     end
@@ -482,24 +476,6 @@ module Mongo
       @refresh_version += 1
     end
 
-    # If we're using async refresh, start
-    # a background thread to run the refresh method
-    # every @refresh_interval seconds.
-    def initiate_refresh_mode
-      if @refresh_mode == :async
-        return if @refresh_thread && @refresh_thread.alive?
-        @refresh_thread = Thread.new do
-          while true do
-            sleep(@refresh_interval)
-            refresh
-          end
-        end
-        @refresh_thread.priority = 1000
-      end
-
-      @last_refresh = Time.now
-    end
-
     # Checkout a socket connected to a node with one of
     # the provided tags. If no such node exists, raise
     # an exception.

test/load/thin/load.rb

@@ -1,7 +1,7 @@
 require File.join(File.dirname(__FILE__), '..', '..', '..', 'lib', 'mongo')
 require 'logger'
 
-$con = Mongo::ReplSetConnection.new(['localhost', 30000], ['localhost', 30001], :read => :secondary, :refresh_mode => :async, :refresh_interval => 30)
+$con = Mongo::ReplSetConnection.new(['localhost', 30000], ['localhost', 30001], :read => :secondary, :refresh_mode => :sync, :refresh_interval => 30)
 $db = $con['foo']
 
 class Load < Sinatra::Base