705 lines
22 KiB
Ruby
705 lines
22 KiB
Ruby
# --
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# Copyright (C) 2008-2010 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 'set'
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require 'socket'
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require 'thread'
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module Mongo
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# Instantiates and manages connections to MongoDB.
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class Connection
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# Abort connections if a ConnectionError is raised.
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Thread.abort_on_exception = true
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DEFAULT_PORT = 27017
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STANDARD_HEADER_SIZE = 16
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RESPONSE_HEADER_SIZE = 20
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MONGODB_URI_MATCHER = /(([.\w\d]+):([\w\d]+)@)?([.\w\d]+)(:([\w\d]+))?(\/([-\d\w]+))?/
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MONGODB_URI_SPEC = "mongodb://[username:password@]host1[:port1][,host2[:port2],...[,hostN[:portN]]][/database]"
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attr_reader :logger, :size, :host, :port, :nodes, :auths, :sockets, :checked_out
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# Counter for generating unique request ids.
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@@current_request_id = 0
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# Create a connection to MongoDB. Specify either one or a pair of servers,
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# along with a maximum connection pool size and timeout.
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#
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# If connecting to just one server, you may specify whether connection to slave is permitted.
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# In all cases, the default host is "localhost" and the default port is 27017.
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#
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# To specify a pair, use Connection.paired.
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#
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# Note that there are a few issues when using connection pooling with Ruby 1.9 on Windows. These
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# should be resolved in the next release.
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#
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# @param [String, Hash] host.
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# @param [Integer] port specify a port number here if only one host is being specified.
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#
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# @option options [Boolean] :slave_ok (false) Must be set to +true+ when connecting
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# to a single, slave node.
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# @option options [Logger, #debug] :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 that can be opened to the database.
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# @option options [Float] :timeout (5.0) When all of the connections to the 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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#
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# @example localhost, 27017
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# Connection.new
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#
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# @example localhost, 27017
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# Connection.new("localhost")
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#
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# @example localhost, 3000, max 5 connections, with max 5 seconds of wait time.
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# Connection.new("localhost", 3000, :pool_size => 5, :timeout => 5)
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#
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# @example localhost, 3000, where this node may be a slave
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# Connection.new("localhost", 3000, :slave_ok => true)
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#
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# @see http://www.mongodb.org/display/DOCS/Replica+Pairs+in+Ruby Replica pairs in Ruby
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#
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# @core connections
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def initialize(host=nil, port=nil, options={})
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@auths = []
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if block_given?
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@nodes = yield self
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else
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@nodes = format_pair(host, port)
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end
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# Host and port of current master.
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@host = @port = nil
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# Lock for request ids.
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@id_lock = Mutex.new
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# Pool size and timeout.
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@size = options[:pool_size] || 1
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@timeout = options[:timeout] || 5.0
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# Mutex for synchronizing pool access
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@connection_mutex = Mutex.new
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@safe_mutex = Mutex.new
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# Condition variable for signal and wait
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@queue = ConditionVariable.new
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@sockets = []
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@checked_out = []
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# slave_ok can be true only if one node is specified
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@slave_ok = options[:slave_ok] && @nodes.length == 1
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@logger = options[:logger] || nil
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@options = options
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should_connect = options[:connect].nil? ? true : options[:connect]
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connect_to_master if should_connect
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end
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# Initialize a paired connection to MongoDB.
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#
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# @param nodes [Array] An array of arrays, each of which specified a host and port.
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# @param opts Takes the same options as Connection.new
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#
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# @example
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# Connection.new([["db1.example.com", 27017],
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# ["db2.example.com", 27017]])
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#
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# @example
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# Connection.new([["db1.example.com", 27017],
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# ["db2.example.com", 27017]],
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# :pool_size => 20, :timeout => 5)
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#
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# @return [Mongo::Connection]
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def self.paired(nodes, opts={})
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unless nodes.length == 2 && nodes.all? {|n| n.is_a? Array}
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raise MongoArgumentError, "Connection.paired requires that exactly two nodes be specified."
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end
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# Block returns an array, the first element being an array of nodes and the second an array
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# of authorizations for the database.
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new(nil, nil, opts) do |con|
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[con.pair_val_to_connection(nodes[0]), con.pair_val_to_connection(nodes[1])]
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end
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end
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# Initialize a connection to MongoDB using the MongoDB URI spec:
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#
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# @param uri [String]
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# A string of the format mongodb://[username:password@]host1[:port1][,host2[:port2],...[,hostN[:portN]]][/database]
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#
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# @param opts Any of the options available for Connection.new
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#
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# @return [Mongo::Connection]
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def self.from_uri(uri, opts={})
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new(nil, nil, opts) do |con|
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con.parse_uri(uri)
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end
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end
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# Apply each of the saved database authentications.
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#
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# @return [Boolean] returns true if authentications exist and succeeed, false
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# if none exists.
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#
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# @raise [AuthenticationError] raises an exception if any one
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# authentication fails.
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def apply_saved_authentication
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return false if @auths.empty?
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@auths.each do |auth|
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self[auth['db_name']].authenticate(auth['username'], auth['password'], false)
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end
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true
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end
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# Save an authentication to this connection. When connecting,
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# the connection will attempt to re-authenticate on every db
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# specificed in the list of auths. This method is called automatically
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# by DB#authenticate.
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#
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# @param [String] db_name
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# @param [String] username
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# @param [String] password
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#
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# @return [Hash] a hash representing the authentication just added.
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def add_auth(db_name, username, password)
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remove_auth(db_name)
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auth = {}
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auth['db_name'] = db_name
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auth['username'] = username
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auth['password'] = password
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@auths << auth
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auth
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end
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# Remove a saved authentication for this connection.
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#
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# @param [String] db_name
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#
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# @return [Boolean]
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def remove_auth(db_name)
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return unless @auths
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if @auths.reject! { |a| a['db_name'] == db_name }
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true
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else
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false
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end
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end
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# Remove all authenication information stored in this connection.
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#
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# @return [true] this operation return true because it always succeeds.
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def clear_auths
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@auths = []
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true
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end
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# Return a hash with all database names
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# and their respective sizes on disk.
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#
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# @return [Hash]
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def database_info
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doc = self['admin'].command({:listDatabases => 1}, false, true)
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returning({}) do |info|
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doc['databases'].each { |db| info[db['name']] = db['sizeOnDisk'].to_i }
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end
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end
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# Return an array of database names.
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#
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# @return [Array]
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def database_names
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database_info.keys
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end
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# Return a database with the given name.
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# See DB#new for valid options hash parameters.
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#
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# @param [String] db_name a valid database name.
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#
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# @return [Mongo::DB]
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#
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# @core databases db-instance_method
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def db(db_name, options={})
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DB.new(db_name, self, options.merge(:logger => @logger))
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end
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# Shortcut for returning a database. Use DB#db to accept options.
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#
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# @param [String] db_name a valid database name.
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#
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# @return [Mongo::DB]
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#
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# @core databases []-instance_method
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def [](db_name)
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DB.new(db_name, self, :logger => @logger)
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end
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# Drop a database.
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#
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# @param [String] name name of an existing database.
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def drop_database(name)
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self[name].command(:dropDatabase => 1)
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end
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# Copy the database +from+ to +to+ on localhost. The +from+ database is
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# assumed to be on localhost, but an alternate host can be specified.
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#
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# @param [String] from name of the database to copy from.
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# @param [String] to name of the database to copy to.
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# @param [String] from_host host of the 'from' database.
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# @param [String] username username for authentication against from_db (>=1.3.x).
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# @param [String] password password for authentication against from_db (>=1.3.x).
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def copy_database(from, to, from_host="localhost", username=nil, password=nil)
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oh = OrderedHash.new
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oh[:copydb] = 1
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oh[:fromhost] = from_host
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oh[:fromdb] = from
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oh[:todb] = to
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if username || password
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unless username && password
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raise MongoArgumentError, "Both username and password must be supplied for authentication."
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end
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nonce_cmd = OrderedHash.new
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nonce_cmd[:copydbgetnonce] = 1
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nonce_cmd[:fromhost] = from_host
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result = self["admin"].command(nonce_cmd, true, true)
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oh[:nonce] = result["nonce"]
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oh[:username] = username
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oh[:key] = Mongo::Support.auth_key(username, password, oh[:nonce])
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end
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self["admin"].command(oh, true, true)
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end
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# Increment and return the next available request id.
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#
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# return [Integer]
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def get_request_id
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request_id = ''
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@id_lock.synchronize do
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request_id = @@current_request_id += 1
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end
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request_id
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end
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# Get the build information for the current connection.
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#
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# @return [Hash]
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def server_info
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self["admin"].command({:buildinfo => 1}, false, true)
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end
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# Get the build version of the current server.
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#
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# @return [Mongo::ServerVersion]
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# object allowing easy comparability of version.
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def server_version
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ServerVersion.new(server_info["version"])
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end
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# Is it okay to connect to a slave?
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#
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# @return [Boolean]
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def slave_ok?
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@slave_ok
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end
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## Connections and pooling ##
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# Send a message to MongoDB, adding the necessary headers.
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#
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# @param [Integer] operation a MongoDB opcode.
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# @param [BSON::ByteBuffer] message a message to send to the database.
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# @param [String] log_message text version of +message+ for logging.
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#
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# @return [True]
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def send_message(operation, message, log_message=nil)
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@logger.debug(" MONGODB #{log_message || message}") if @logger
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begin
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packed_message = add_message_headers(operation, message).to_s
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socket = checkout
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send_message_on_socket(packed_message, socket)
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ensure
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checkin(socket)
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end
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end
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# Sends a message to the database, waits for a response, and raises
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# an exception if the operation has failed.
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#
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# @param [Integer] operation a MongoDB opcode.
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# @param [BSON::ByteBuffer] message a message to send to the database.
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# @param [String] db_name the name of the database. used on call to get_last_error.
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# @param [String] log_message text version of +message+ for logging.
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#
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# @return [Array]
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# An array whose indexes include [0] documents returned, [1] number of document received,
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# and [3] a cursor_id.
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def send_message_with_safe_check(operation, message, db_name, log_message=nil)
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message_with_headers = add_message_headers(operation, message)
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message_with_check = last_error_message(db_name)
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@logger.debug(" MONGODB #{log_message || message}") if @logger
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begin
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sock = checkout
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packed_message = message_with_headers.append!(message_with_check).to_s
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docs = num_received = cursor_id = ''
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@safe_mutex.synchronize do
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send_message_on_socket(packed_message, sock)
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docs, num_received, cursor_id = receive(sock)
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end
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ensure
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checkin(sock)
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end
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if num_received == 1 && error = docs[0]['err']
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raise Mongo::OperationFailure, error
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end
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[docs, num_received, cursor_id]
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end
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# Sends a message to the database and waits for the response.
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#
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# @param [Integer] operation a MongoDB opcode.
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# @param [BSON::ByteBuffer] message a message to send to the database.
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# @param [String] log_message text version of +message+ for logging.
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# @param [Socket] socket a socket to use in lieu of checking out a new one.
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#
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# @return [Array]
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# An array whose indexes include [0] documents returned, [1] number of document received,
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# and [3] a cursor_id.
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def receive_message(operation, message, log_message=nil, socket=nil)
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packed_message = add_message_headers(operation, message).to_s
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@logger.debug(" MONGODB #{log_message || message}") if @logger
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begin
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sock = socket || checkout
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result = ''
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@safe_mutex.synchronize do
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send_message_on_socket(packed_message, sock)
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result = receive(sock)
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end
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ensure
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checkin(sock)
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end
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result
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end
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# Create a new socket and attempt to connect to master.
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# If successful, sets host and port to master and returns the socket.
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#
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# @raise [ConnectionFailure] if unable to connect to any host or port.
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def connect_to_master
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close
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@host = @port = nil
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for node_pair in @nodes
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host, port = *node_pair
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begin
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socket = TCPSocket.new(host, port)
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socket.setsockopt(Socket::IPPROTO_TCP, Socket::TCP_NODELAY, 1)
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# If we're connected to master, set the @host and @port
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result = self['admin'].command({:ismaster => 1}, false, false, socket)
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if result['ok'] == 1 && ((is_master = result['ismaster'] == 1) || @slave_ok)
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@host, @port = host, port
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apply_saved_authentication
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end
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# Note: slave_ok can be true only when connecting to a single node.
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if @nodes.length == 1 && !is_master && !@slave_ok
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raise ConfigurationError, "Trying to connect directly to slave; " +
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"if this is what you want, specify :slave_ok => true."
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end
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break if is_master || @slave_ok
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rescue SocketError, SystemCallError, IOError => ex
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socket.close if socket
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close
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false
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end
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end
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raise ConnectionFailure, "failed to connect to any given host:port" unless socket
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end
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# Are we connected to MongoDB? This is determined by checking whether
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# host and port have values, since they're set to nil on calls to #close.
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def connected?
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@host && @port
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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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@sockets.each do |sock|
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sock.close
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end
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@host = @port = nil
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@sockets.clear
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@checked_out.clear
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end
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## Configuration helper methods
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# Returns an array of host-port pairs.
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#
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# @private
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def format_pair(pair_or_host, port)
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case pair_or_host
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when String
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[[pair_or_host, port ? port.to_i : DEFAULT_PORT]]
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when nil
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[['localhost', DEFAULT_PORT]]
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end
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end
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# Convert an argument containing a host name string and a
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# port number integer into a [host, port] pair array.
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#
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# @private
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def pair_val_to_connection(a)
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case a
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when nil
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['localhost', DEFAULT_PORT]
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when String
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[a, DEFAULT_PORT]
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when Integer
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['localhost', a]
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when Array
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a
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end
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end
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# Parse a MongoDB URI. This method is used by Connection.from_uri.
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# Returns an array of nodes and an array of db authorizations, if applicable.
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#
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# @private
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def parse_uri(string)
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if string =~ /^mongodb:\/\//
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string = string[10..-1]
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else
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raise MongoArgumentError, "MongoDB URI must match this spec: #{MONGODB_URI_SPEC}"
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end
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nodes = []
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auths = []
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specs = string.split(',')
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specs.each do |spec|
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matches = MONGODB_URI_MATCHER.match(spec)
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if !matches
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raise MongoArgumentError, "MongoDB URI must match this spec: #{MONGODB_URI_SPEC}"
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end
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uname = matches[2]
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pwd = matches[3]
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host = matches[4]
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port = matches[6] || DEFAULT_PORT
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if !(port.to_s =~ /^\d+$/)
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raise MongoArgumentError, "Invalid port #{port}; port must be specified as digits."
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end
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port = port.to_i
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db = matches[8]
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if (uname || pwd || db) && !(uname && pwd && db)
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raise MongoArgumentError, "MongoDB URI must include all three of username, password, " +
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"and db if any one of these is specified."
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else
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add_auth(db, uname, pwd)
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end
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nodes << [host, port]
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end
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nodes
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end
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private
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|
|
# 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_to_master 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 "Waiting for available connection; #{@checked_out.size} of #{@size} connections checked out."
|
|
end
|
|
@queue.wait(@connection_mutex)
|
|
end
|
|
end
|
|
end
|
|
|
|
def receive(sock)
|
|
receive_header(sock)
|
|
number_received, cursor_id = receive_response_header(sock)
|
|
read_documents(number_received, cursor_id, sock)
|
|
end
|
|
|
|
def receive_header(sock)
|
|
header = BSON::ByteBuffer.new
|
|
header.put_array(receive_message_on_socket(16, sock).unpack("C*"))
|
|
unless header.size == STANDARD_HEADER_SIZE
|
|
raise "Short read for DB response header: " +
|
|
"expected #{STANDARD_HEADER_SIZE} bytes, saw #{header.size}"
|
|
end
|
|
header.rewind
|
|
size = header.get_int
|
|
request_id = header.get_int
|
|
response_to = header.get_int
|
|
op = header.get_int
|
|
end
|
|
|
|
def receive_response_header(sock)
|
|
header_buf = BSON::ByteBuffer.new
|
|
header_buf.put_array(receive_message_on_socket(RESPONSE_HEADER_SIZE, sock).unpack("C*"))
|
|
if header_buf.length != RESPONSE_HEADER_SIZE
|
|
raise "Short read for DB response header; " +
|
|
"expected #{RESPONSE_HEADER_SIZE} bytes, saw #{header_buf.length}"
|
|
end
|
|
header_buf.rewind
|
|
result_flags = header_buf.get_int
|
|
cursor_id = header_buf.get_long
|
|
starting_from = header_buf.get_int
|
|
number_remaining = header_buf.get_int
|
|
[number_remaining, cursor_id]
|
|
end
|
|
|
|
def read_documents(number_received, cursor_id, sock)
|
|
docs = []
|
|
number_remaining = number_received
|
|
while number_remaining > 0 do
|
|
buf = BSON::ByteBuffer.new
|
|
buf.put_array(receive_message_on_socket(4, sock).unpack("C*"))
|
|
buf.rewind
|
|
size = buf.get_int
|
|
buf.put_array(receive_message_on_socket(size - 4, sock).unpack("C*"), 4)
|
|
number_remaining -= 1
|
|
buf.rewind
|
|
docs << BSON::BSON_CODER.deserialize(buf)
|
|
end
|
|
[docs, number_received, cursor_id]
|
|
end
|
|
|
|
def last_error_message(db_name)
|
|
message = BSON::ByteBuffer.new
|
|
message.put_int(0)
|
|
BSON::BSON_RUBY.serialize_cstr(message, "#{db_name}.$cmd")
|
|
message.put_int(0)
|
|
message.put_int(-1)
|
|
message.put_array(BSON::BSON_CODER.serialize({:getlasterror => 1}, false).unpack("C*"))
|
|
add_message_headers(Mongo::Constants::OP_QUERY, message)
|
|
end
|
|
|
|
# Prepares a message for transmission to MongoDB by
|
|
# constructing a valid message header.
|
|
def add_message_headers(operation, message)
|
|
headers = BSON::ByteBuffer.new
|
|
|
|
# Message size.
|
|
headers.put_int(16 + message.size)
|
|
|
|
# Unique request id.
|
|
headers.put_int(get_request_id)
|
|
|
|
# Response id.
|
|
headers.put_int(0)
|
|
|
|
# Opcode.
|
|
headers.put_int(operation)
|
|
message.prepend!(headers)
|
|
end
|
|
|
|
# Low-level method for sending a message on a socket.
|
|
# Requires a packed message and an available socket,
|
|
def send_message_on_socket(packed_message, socket)
|
|
begin
|
|
socket.send(packed_message, 0)
|
|
rescue => ex
|
|
close
|
|
raise ConnectionFailure, "Operation failed with the following exception: #{ex}"
|
|
end
|
|
end
|
|
|
|
# Low-level method for receiving data from socket.
|
|
# Requires length and an available socket.
|
|
def receive_message_on_socket(length, socket)
|
|
message = ""
|
|
begin
|
|
while message.length < length do
|
|
chunk = socket.recv(length - message.length)
|
|
raise ConnectionFailure, "connection closed" unless chunk.length > 0
|
|
message += chunk
|
|
end
|
|
rescue => ex
|
|
close
|
|
raise ConnectionFailure, "Operation failed with the following exception: #{ex}"
|
|
end
|
|
message
|
|
end
|
|
end
|
|
end
|