489 lines
16 KiB
Ruby
489 lines
16 KiB
Ruby
# encoding: UTF-8
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# --
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# Copyright (C) 2008-2011 10gen Inc.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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# ++
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require 'sync'
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module Mongo
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# Instantiates and manages connections to a MongoDB replica set.
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class ReplSetConnection < Connection
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attr_reader :secondaries, :arbiters, :secondary_pools,
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:replica_set_name, :read_pool, :seeds, :tag_map,
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:refresh_interval, :refresh_mode
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# Create a connection to a MongoDB replica set.
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#
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# Once connected to a replica set, you can find out which nodes are primary, secondary, and
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# arbiters with the corresponding accessors: Connection#primary, Connection#secondaries, and
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# Connection#arbiters. This is useful if your application needs to connect manually to nodes other
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# than the primary.
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#
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# @param [Array] args A list of host-port pairs to be used as seed nodes followed by a
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# hash containing any options. See the examples below for exactly how to use the constructor.
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#
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# @option options [String] :rs_name (nil) The name of the replica set to connect to. You
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# can use this option to verify that you're connecting to the right replica set.
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# @option options [Boolean, Hash] :safe (false) Set the default safe-mode options
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# propogated to DB objects instantiated off of this Connection. This
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# default can be overridden upon instantiation of any DB by explicity setting a :safe value
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# on initialization.
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# @option options [:primary, :secondary] :read (:primary) The default read preference for Mongo::DB
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# objects created from this connection object. If +:secondary+ is chosen, reads will be sent
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# to one of the closest available secondary nodes. If a secondary node cannot be located, the
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# read will be sent to the primary.
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# @option options [Logger] :logger (nil) Logger instance to receive driver operation log.
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# @option options [Integer] :pool_size (1) The maximum number of socket connections allowed per
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# connection pool. Note: this setting is relevant only for multi-threaded applications.
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# @option options [Float] :pool_timeout (5.0) When all of the connections a pool are checked out,
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# this is the number of seconds to wait for a new connection to be released before throwing an exception.
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# Note: this setting is relevant only for multi-threaded applications.
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# @option opts [Float] :op_timeout (nil) The number of seconds to wait for a read operation to time out.
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# Disabled by default.
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# @option opts [Float] :connect_timeout (nil) The number of seconds to wait before timing out a
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# connection attempt.
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# @option opts [Boolean] :ssl (false) If true, create the connection to the server using SSL.
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# @option opts [Boolean] :refresh_mode (:sync) Set this to :async to enable a background thread that
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# periodically updates the state of the connection. If, for example, you initially connect while a secondary
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# is down, this will reconnect to that secondary behind the scenes to
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# prevent you from having to reconnect manually. If set to :sync, refresh will happen
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# synchronously. If +false+, no automatic refresh will occur unless there's a connection failure.
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# @option opts [Integer] :refresh_interval (90) If :refresh_mode is enabled, this is the number of seconds
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# between calls to check the replica set's state.
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# @option opts [Boolean] :require_primary (true) If true, require a primary node for the connection
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# to succeed. Otherwise, connection will succeed as long as there's at least one secondary node.
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#
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# @example Connect to a replica set and provide two seed nodes. Note that the number of seed nodes does
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# not have to be equal to the number of replica set members. The purpose of seed nodes is to permit
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# the driver to find at least one replica set member even if a member is down.
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# ReplSetConnection.new(['localhost', 30000], ['localhost', 30001])
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#
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# @example Connect to a replica set providing two seed nodes and ensuring a connection to the replica set named 'prod':
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# ReplSetConnection.new(['localhost', 30000], ['localhost', 30001], :rs_name => 'prod')
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#
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# @example Connect to a replica set providing two seed nodes and allowing reads from a secondary node:
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# ReplSetConnection.new(['localhost', 30000], ['localhost', 30001], :read_secondary => true)
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#
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# @see http://api.mongodb.org/ruby/current/file.REPLICA_SETS.html Replica sets in Ruby
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#
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# @raise [ReplicaSetConnectionError] This is raised if a replica set name is specified and the
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# driver fails to connect to a replica set with that name.
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def initialize(*args)
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extend Sync_m
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if args.last.is_a?(Hash)
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opts = args.pop
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else
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opts = {}
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end
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unless args.length > 0
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raise MongoArgumentError, "A ReplSetConnection requires at least one seed node."
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end
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# The list of seed nodes
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@seeds = args
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# TODO: get rid of this
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@nodes = @seeds.dup
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# Connection pool for primary node
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@primary = nil
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@primary_pool = nil
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# Connection pools for each secondary node
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@secondaries = []
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@secondary_pools = []
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# The secondary pool to which we'll be sending reads.
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# This may be identical to the primary pool.
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@read_pool = nil
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# A list of arbiter addresses (for client information only)
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@arbiters = []
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# Refresh
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@refresh_mode = opts.fetch(:refresh_mode, :sync)
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@refresh_interval = opts[:refresh_interval] || 90
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if ![:sync, :async, false].include?(@refresh_mode)
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raise MongoArgumentError,
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"Refresh mode must be one of :sync, :async, or false."
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end
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# Are we allowing reads from secondaries?
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if opts[:read_secondary]
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warn ":read_secondary options has now been deprecated and will " +
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"be removed in driver v2.0. Use the :read option instead."
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@read_secondary = opts.fetch(:read_secondary, false)
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@read = :secondary
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else
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@read = opts.fetch(:read, :primary)
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Mongo::Support.validate_read_preference(@read)
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end
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@connected = false
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# Store the refresher thread
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@refresh_thread = nil
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# Maps
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@sockets_to_pools = {}
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@tag_map = nil
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# Replica set name
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if opts[:rs_name]
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warn ":rs_name option has been deprecated and will be removed in v2.0. " +
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"Please use :name instead."
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@replica_set_name = opts[:rs_name]
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else
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@replica_set_name = opts[:name]
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end
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# Require a primary node to connect?
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@require_primary = opts.fetch(:require_primary, true)
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setup(opts)
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end
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def inspect
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"<Mongo::ReplSetConnection:0x#{self.object_id.to_s(16)} @seeds=#{@seeds.inspect} " +
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"@connected=#{@connected}>"
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end
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# Initiate a connection to the replica set.
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def connect
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log(:info, "Connecting...")
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sync_synchronize(:EX) do
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return if @connected
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manager = PoolManager.new(self, @seeds)
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manager.connect
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update_config(manager)
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initiate_refresh_mode
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if @require_primary && @primary.nil? #TODO: in v2.0, we'll let this be optional and do a lazy connect.
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raise ConnectionFailure, "Failed to connect to primary node."
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elsif !@read_pool
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raise ConnectionFailure, "Failed to connect to any node."
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else
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@connected = true
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end
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end
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end
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# Refresh the current replica set configuration.
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# This method will attempt to do a soft refresh,
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# updating only those parts of the replica set that
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# have changed. If that's not possible, the method
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# will perform a hard refresh.
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#
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# @return [Boolean] +true+ if hard refresh
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# occurred. +false+ is returned when unable
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# to get the refresh lock.
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def refresh(opts={})
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if !connected?
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log(:info, "Trying to refresh but not connected..." +
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"skipping replica set health check.")
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hard_refresh!
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return true
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end
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log(:info, "Checking replica set connection health...")
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@manager.check_connection_health
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if @manager.refresh_required?
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hard_refresh!
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end
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return true
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end
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# Force a hard refresh of this connection's view
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# of the replica set.
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#
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# @return [Boolean] +true+ if hard refresh
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# occurred. +false+ is returned when unable
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# to get the refresh lock.
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def hard_refresh!
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return false if sync_exclusive?
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log(:info, "Initiating hard refresh...")
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@background_manager = PoolManager.new(self, @seeds)
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@background_manager.connect
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sync_synchronize(:EX) do
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update_config(@background_manager)
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end
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return true
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end
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def connected?
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!@primary_pool.nil? || !@read_pool.nil?
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end
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# @deprecated
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def connecting?
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warn "ReplSetConnection#connecting? is deprecated and will be removed in v2.0."
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false
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end
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# The replica set primary's host name.
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#
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# @return [String]
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def host
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super
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end
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# The replica set primary's port.
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#
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# @return [Integer]
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def port
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super
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end
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def nodes
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warn "ReplSetConnection#nodes is DEPRECATED and will be removed in v2.0. " +
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"Please use ReplSetConnection#seeds instead."
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@seeds
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end
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# Determine whether we're reading from a primary node. If false,
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# this connection connects to a secondary node and @read_secondaries is true.
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#
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# @return [Boolean]
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def read_primary?
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sync_synchronize(:SH) do
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@read_pool == @primary_pool
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end
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end
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alias :primary? :read_primary?
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def read_preference
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@read
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end
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# Close the connection to the database.
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def close
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sync_synchronize(:EX) do
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@connected = false
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super
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if @refresh_thread
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@refresh_thread.kill
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@refresh_thread = nil
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end
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@read_pool = nil
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if @secondary_pools
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@secondary_pools.each do |pool|
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pool.close
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end
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end
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@secondaries = []
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@secondary_pools = []
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@arbiters = []
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@tag_map = nil
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@sockets_to_pools.clear
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end
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end
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# If a ConnectionFailure is raised, this method will be called
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# to close the connection and reset connection values.
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# @deprecated
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def reset_connection
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close
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warn "ReplSetConnection#reset_connection is now deprecated and will be removed in v2.0. " +
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"Use ReplSetConnection#close instead."
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end
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# Returns +true+ if it's okay to read from a secondary node.
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# Since this is a replica set, this must always be true.
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#
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# This method exist primarily so that Cursor objects will
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# generate query messages with a slaveOkay value of +true+.
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#
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# @return [Boolean] +true+
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def slave_ok?
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true
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end
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def authenticate_pools
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super
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@secondary_pools.each do |pool|
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pool.authenticate_existing
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end
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end
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def logout_pools(db)
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super
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@secondary_pools.each do |pool|
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pool.logout_existing(db)
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end
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end
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private
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# Given a pool manager, update this connection's
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# view of the replica set.
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#
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# This method must be called within
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# an exclusive lock.
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def update_config(manager)
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@arbiters = manager.arbiters.nil? ? [] : manager.arbiters.dup
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@primary = manager.primary.nil? ? nil : manager.primary.dup
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@secondaries = manager.secondaries.dup
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@hosts = manager.hosts.dup
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@primary_pool = manager.primary_pool
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@read_pool = manager.read_pool
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@secondary_pools = manager.secondary_pools
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@tag_map = manager.tag_map
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@seeds = manager.seeds
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@manager = manager
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@nodes = manager.nodes
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@max_bson_size = manager.max_bson_size
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end
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def initiate_refresh_mode
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if @refresh_mode == :async
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return if @refresh_thread && @refresh_thread.alive?
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@refresh_thread = Thread.new do
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while true do
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sleep(@refresh_interval)
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refresh
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end
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end
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end
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@last_refresh = Time.now
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end
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# Checkout a socket for reading (i.e., a secondary node).
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# Note that @read_pool might point to the primary pool
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# if no read pool has been defined.
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def checkout_reader
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connect unless connected?
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socket = get_socket_from_pool(@read_pool)
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if !socket
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refresh
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socket = get_socket_from_pool(@primary_pool)
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end
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if socket
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socket
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else
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raise ConnectionFailure.new("Could not connect to a node for reading.")
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end
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end
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# Checkout a socket connected to a node with one of
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# the provided tags. If no such node exists, raise
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# an exception.
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#
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# NOTE: will be available in driver release v2.0.
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def checkout_tagged(tags)
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sync_synchronize(:SH) do
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tags.each do |k, v|
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pool = @tag_map[{k.to_s => v}]
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if pool
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socket = pool.checkout
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@sockets_to_pools[socket] = pool
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return socket
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end
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end
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end
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raise NodeWithTagsNotFound,
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"Could not find a connection tagged with #{tags}."
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end
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# Checkout a socket for writing (i.e., a primary node).
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def checkout_writer
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connect unless connected?
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socket = get_socket_from_pool(@primary_pool)
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if !socket
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refresh
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socket = get_socket_from_pool(@primary_pool)
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end
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if socket
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socket
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else
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raise ConnectionFailure.new("Could not connect to primary node.")
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end
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end
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def get_socket_from_pool(pool)
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begin
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sync_synchronize(:SH) do
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if pool
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socket = pool.checkout
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@sockets_to_pools[socket] = pool
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socket
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end
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end
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rescue ConnectionFailure => ex
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log(:info, "Failed to checkout from #{pool} with #{ex.class}; #{ex.message}")
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return nil
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end
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end
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# Checkin a socket used for reading.
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def checkin_reader(socket)
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warn "ReplSetConnection#checkin_writer is deprecated and will be removed " +
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"in driver v2.0. Use ReplSetConnection#checkin instead."
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checkin(socket)
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end
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# Checkin a socket used for writing.
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def checkin_writer(socket)
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warn "ReplSetConnection#checkin_writer is deprecated and will be removed " +
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"in driver v2.0. Use ReplSetConnection#checkin instead."
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checkin(socket)
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end
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def checkin(socket)
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sync_synchronize(:SH) do
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if pool = @sockets_to_pools[socket]
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pool.checkin(socket)
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elsif socket
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begin
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socket.close
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rescue IOError
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log(:info, "Tried to close socket #{socket} but already closed.")
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end
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end
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end
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# Refresh synchronously every @refresh_interval seconds
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# if synchronous refresh mode is enabled.
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if @refresh_mode == :sync &&
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((Time.now - @last_refresh) > @refresh_interval)
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refresh
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@last_refresh = Time.now
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end
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end
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end
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end
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