Fixes for replica pairs.

README.rdoc

@@ -255,7 +255,21 @@ If you have the source code, you can run the tests.
 
   $ rake test
 
-The tests now require shoulda and mocha.  You can install these gems as
+This will run both unit and functional tests. If you want to run these
+individually:
+
+  $ rake test:unit
+  $ rake test:functional
+
+
+If you want to test replica pairs, you can run the following tests
+individually:
+
+  $ rake test:pair_count
+  $ rake test:pair_insert
+  $ rake test:pair_query
+
+All tests now require shoulda and mocha.  You can install these gems as
 follows:
 
   $ gem install shoulda

Rakefile

@@ -32,8 +32,13 @@ namespace :test do
     t.verbose    = true
   end
 
+  Rake::TestTask.new(:pair_count) do |t|
+    t.test_files = FileList['test/replica/count_test.rb']
+    t.verbose    = true
+  end
+
   Rake::TestTask.new(:pair_insert) do |t|
-    t.test_files = FileList['test/replica/pair_test.rb']
+    t.test_files = FileList['test/replica/insert_test.rb']
     t.verbose    = true
   end
 

lib/mongo/connection.rb

@@ -39,12 +39,10 @@ module Mongo
     #              see if the server is the master. If it is not, an error
     #              is thrown.
     #
-    # :auto_reconnect :: If a DB connection gets closed (for example, we
+    # :auto_reconnect :: DEPRECATED. When an operation fails, a
-    #                    have a server pair and saw the "not master"
+    # ConnectionFailure will be raised. The client is encouraged to retry the
-    #                    error, which closes the connection), then
+    # operation as necessary.
-    #                    automatically try to reconnect to the master or
+    #
-    #                    to the single server we have been given. Defaults
-    #                    to +false+.
     # :logger :: Optional Logger instance to which driver usage information
     #            will be logged.
     #

lib/mongo/cursor.rb

@@ -63,9 +63,12 @@ module Mongo
         # pair but it has died or something like that) then we close that
         # connection. If the db has auto connect option and a pair of
         # servers, next request will re-open on master server.
-        @db.close if err == "not master"
+        if err == "not master"
+          raise ConnectionFailure, err
+          @db.close
+        end
 
-        raise err
+        raise OperationFailure, err
       end
 
       o

lib/mongo/db.rb

@@ -69,7 +69,6 @@ module Mongo
     attr_reader :logger
 
     def slave_ok?; @slave_ok; end
-    def auto_reconnect?; @auto_reconnect; end
 
     # A primary key factory object (or +nil+). See the README.doc file or
     # DB#new for details.
@@ -110,15 +109,13 @@ module Mongo
     #              see if the server is the master. If it is not, an error
     #              is thrown.
     #
-    # :auto_reconnect :: If the connection gets closed (for example, we
-    #                    have a server pair and saw the "not master"
-    #                    error, which closes the connection), then
-    #                    automatically try to reconnect to the master or
-    #                    to the single server we have been given. Defaults
-    #                    to +false+.
     # :logger :: Optional Logger instance to which driver usage information
     #            will be logged.
     #
+    # :auto_reconnect :: DEPRECATED. When an operation fails, a
+    # ConnectionFailure will be raised. The client is encouraged to retry the
+    # operation as necessary.
+    #
     # When a DB object first connects to a pair, it will find the master
     # instance and connect to that one. On socket error or if we recieve a
     # "not master" error, we again find the master of the pair.
@@ -144,7 +141,10 @@ module Mongo
       @strict = options[:strict]
       @pk_factory = options[:pk]
       @slave_ok = options[:slave_ok] && @nodes.length == 1 # only OK if one node
-      @auto_reconnect = options[:auto_reconnect]
+      if options[:auto_reconnect]
+        warn(":auto_reconnect is deprecated. henceforth, any time an operation fails, " + 
+             "the driver will attempt to reconnect master on subsequent operations.")
+      end
       @semaphore = Mutex.new
       @socket = nil
       @logger = options[:logger]
@@ -177,7 +177,7 @@ module Mongo
           false
         end
       }
-      raise "error: failed to connect to any given host:port" unless @socket
+      raise ConnectionFailure, "error: failed to connect to any given host:port" unless @socket
     end
 
     # Returns true if +username+ has +password+ in
@@ -457,49 +457,28 @@ module Mongo
       message_with_check   = last_error_message
       @logger.debug("  MONGODB #{log_message || message}") if @logger
       @semaphore.synchronize do
-        safe_send do 
         send_message_on_socket(message_with_headers.append!(message_with_check).to_s)
         docs, num_received, cursor_id = receive
         if num_received == 1 && error = docs[0]['err']
+          if docs[0]['err'] == 'not master'
+            raise ConnectionFailure
+          else
             raise Mongo::OperationFailure, error
+          end
         else
           true
         end
       end
     end
-    end
 
     # Send a message to the database and waits for the response.
     def receive_message_with_operation(operation, message, log_message=nil)
       message_with_headers = add_message_headers(operation, message).to_s
       @logger.debug("  MONGODB #{log_message || message}") if @logger
       @semaphore.synchronize do
-        response = ""
-        safe_send do 
         send_message_on_socket(message_with_headers)
-          response = receive
+        receive
       end
-        response
-      end
-    end
-
-    # Capture errors and try to reconnect
-    def safe_send
-      sent = false
-      while(!sent) do 
-      begin
-        response = yield
-        sent = true
-        rescue Timeout::Error, SocketError, SystemCallError, IOError, ConnectionFailure => ex
-          if @auto_reconnect
-            connect_to_master
-          else
-            raise ex
-            close
-          end
-        end
-      end
-      response
     end
 
     # Return +true+ if +doc+ contains an 'ok' field with the value 1.
@@ -610,28 +589,19 @@ module Mongo
 
     # Sending a message on socket.
     def send_message_on_socket(packed_message)
-      connect_to_master if !connected? && @auto_reconnect
+      connect_to_master if !connected?
-      sent = false
-      while !sent do 
       begin
         @socket.print(packed_message)
         @socket.flush
-          sent = true
       rescue => ex
-          sent = false
-          if @auto_reconnect
-            connect_to_master
-          else
         close
-            raise ex
+        raise ConnectionFailure, "Operation failed with the following exception: #{ex}."
-          end
-        end
       end
     end
 
     # Receive data of specified length on socket.
     def receive_data_on_socket(length)
-      connect_to_master if !connected? && @auto_reconnect
+      connect_to_master if !connected?
       message = ""
       chunk   = ""
       while message.length < length do
@@ -639,8 +609,8 @@ module Mongo
           chunk = @socket.read(length - message.length)
           raise ConnectionFailure, "connection closed" unless chunk && chunk.length > 0
           message += chunk
-        rescue Timeout => ex
+        rescue => ex
-          raise OperationFailure, "Database command timed out."
+          raise ConnectionFailure, "Operation failed with the following exception: #{ex}"
         end
       end
       message

test/replica/count_test.rb

@@ -0,0 +1,34 @@
+$:.unshift(File.join(File.dirname(__FILE__), '..', 'lib'))
+require 'mongo'
+require 'test/unit'
+require 'test/test_helper'
+
+# NOTE: this test should be run only if a replica pair is running.
+class CountTest < Test::Unit::TestCase
+  include Mongo
+ 
+  def setup 
+    @conn = Mongo::Connection.new({:left => ["localhost", 27017], :right => ["localhost", 27018]}, nil)
+    @db = @conn.db('mongo-ruby-test')
+    @db.drop_collection("test-pairs")
+    @coll = @db.collection("test-pairs")
+  end
+
+  def test_correct_count_after_insertion_reconnect
+    @coll.insert({:a => 20}, :safe => true)
+    assert_equal 1, @coll.count
+
+    # Sleep to allow resync
+    sleep(3)
+
+    puts "Please disconnect the current master."
+    gets
+
+    rescue_connection_failure do 
+      @coll.insert({:a => 30}, :safe => true)
+    end
+    @coll.insert({:a => 40}, :safe => true)
+    assert_equal 3, @coll.count, "Second count failed"
+  end
+
+end

test/replica/insert_test.rb

@@ -0,0 +1,51 @@
+$:.unshift(File.join(File.dirname(__FILE__), '..', 'lib'))
+require 'mongo'
+require 'test/unit'
+require 'test/test_helper'
+
+# NOTE: this test should be run only if a replica pair is running.
+class ReplicaPairTest < Test::Unit::TestCase
+  include Mongo
+ 
+  def setup 
+    @conn = Mongo::Connection.new({:left => ["localhost", 27017], :right => ["localhost", 27018]}, nil)
+    @db = @conn.db('mongo-ruby-test')
+    @db.drop_collection("test-pairs")
+    @coll = @db.collection("test-pairs")
+  end
+
+  def test_insert
+    @coll.save({:a => 20}, :safe => true)
+    puts "Please disconnect the current master."
+    gets
+
+    rescue_connection_failure do 
+      @coll.save({:a => 30}, :safe => true)
+    end
+
+    @coll.save({:a => 40}, :safe => true)
+    @coll.save({:a => 50}, :safe => true)
+    @coll.save({:a => 60}, :safe => true)
+    @coll.save({:a => 70}, :safe => true)
+
+    puts "Please reconnect the old master to make sure that the new master " + 
+         "has synced with the previous master. Note: this may have happened already."
+    gets
+    results = []
+    
+    # Note: need to figure out what to do here since this first find will fail.
+    rescue_connection_failure do 
+      @coll.find.each {|r| results << r}
+      [20, 30, 40, 50, 60, 70].each do |a|
+        assert results.any? {|r| r['a'] == a}, "Could not find record for a => #{a}"
+      end
+    end
+
+    @coll.save({:a => 80}, :safe => true)
+    @coll.find.each {|r| results << r}
+    [20, 30, 40, 50, 60, 70, 80].each do |a|
+      assert results.any? {|r| r['a'] == a}, "Could not find record for a => #{a} on second find"
+    end
+  end
+
+end

test/replica/pair_test.rb

@@ -1,36 +0,0 @@
-$LOAD_PATH[0,0] = File.join(File.dirname(__FILE__), '..', 'lib')
-require 'mongo'
-require 'test/unit'
-
-# NOTE: this test should be run only if 
-class ReplicaPairTest < Test::Unit::TestCase
-  include Mongo
- 
-  def setup 
-    @conn = Mongo::Connection.new({:left => ["localhost", 27017], :right => ["localhost", 27018]}, nil, :auto_reconnect => true)
-    @db = @conn.db('mongo-ruby-test')
-    @db.drop_collection("test-pairs")
-    @coll = @db.collection("test-pairs")
-  end
-
-  def test_insert
-    @coll.save({:a => 20}, :safe => true)
-    puts "Please disconnect the current master. Test will resume in 15 seconds."
-    sleep(15)
-    @coll.save({:a => 30}, :safe => true)
-    @coll.save({:a => 40}, :safe => true)
-    @coll.save({:a => 50}, :safe => true)
-    @coll.save({:a => 60}, :safe => true)
-    @coll.save({:a => 70}, :safe => true)
-    puts "Please reconnect the old master. Test will resume in 15 seconds."
-    sleep(15)
-    results = []
-    # Note: need to figure out what to do here.
-    @coll.find.each {|r| r}
-    @coll.find.each {|r| results << r}
-    [20, 30, 40, 50, 60, 70].each do |a|
-      assert results.any? {|r| r['a'] == a}, "Could not find record for a => #{a}"
-    end
-  end
-
-end

test/replica/query_test.rb

@@ -1,13 +1,14 @@
-$LOAD_PATH[0,0] = File.join(File.dirname(__FILE__), '..', 'lib')
+$:.unshift(File.join(File.dirname(__FILE__), '..', 'lib'))
 require 'mongo'
 require 'test/unit'
+require 'test/test_helper'
 
-# NOTE: this test should be run only if 
+# NOTE: this test should be run only if a replica pair is running.
 class ReplicaPairTest < Test::Unit::TestCase
   include Mongo
  
   def setup 
-    @conn = Mongo::Connection.new({:left => ["localhost", 27017], :right => ["localhost", 27018]}, nil, :auto_reconnect => true)
+    @conn = Mongo::Connection.new({:left => ["localhost", 27017], :right => ["localhost", 27018]}, nil)
     @db = @conn.db('mongo-ruby-test')
     @db.drop_collection("test-pairs")
     @coll = @db.collection("test-pairs")
@@ -18,16 +19,21 @@ class ReplicaPairTest < Test::Unit::TestCase
     @coll.save({:a => 30})
     @coll.save({:a => 40})
     results = []
-    @coll.find.each {|r| p results << r}
+    @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
-    puts "Please disconnect the current master. Test will resume in 15 seconds."
+
-    sleep(15)
+    puts "Please disconnect the current master."
-    @coll.find.each {|r| p results << r}
+    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/test_db.rb

@@ -144,21 +144,6 @@ class DBTest < Test::Unit::TestCase
     @@db.logout                  # only testing that we don't throw exception
   end
 
-  def test_auto_connect
-    @@db.close
-    db = Connection.new(@@host, @@port, :auto_reconnect => true).db('ruby-mongo-test')
-    assert db.connected?
-    assert db.auto_reconnect?
-    db.close
-    assert !db.connected?
-    assert db.auto_reconnect?
-    db.collection('test').insert('a' => 1)
-    assert db.connected?
-  ensure
-    @@db = Connection.new(@@host, @@port).db('ruby-mongo-test')
-    @@users = @@db.collection('system.users')
-  end
-
   def test_error
     @@db.reset_error_history
     assert_nil @@db.error

test/test_db_api.rb

@@ -776,7 +776,7 @@ class DBAPITest < Test::Unit::TestCase
   # doesn't really test functionality, just that the option is set correctly
   def test_snapshot
     @@db.collection("test").find({}, :snapshot => true).to_a
-    assert_raise RuntimeError do
+    assert_raise OperationFailure do
       @@db.collection("test").find({}, :snapshot => true, :sort => 'a').to_a
     end
   end

test/test_helper.rb

@@ -22,4 +22,19 @@ require 'mongo'
 # NOTE: most tests assume that MongoDB is running.
 class Test::Unit::TestCase
   include Mongo
+
+  # Generic code for rescuing connection failures and retrying operations.
+  # This could be combined with some timeout functionality.
+  def rescue_connection_failure
+    success = false
+    while !success
+      begin
+        yield
+        success = true
+      rescue Mongo::ConnectionFailure
+        puts "Rescuing"
+        sleep(1)
+      end
+    end
+  end
 end