mongo-ruby-driver/lib/mongo/connection.rb

705 lines
22 KiB
Ruby

# --
# Copyright (C) 2008-2010 10gen Inc.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
# ++
require 'set'
require 'socket'
require 'thread'
module Mongo
# Instantiates and manages connections to MongoDB.
class Connection
# Abort connections if a ConnectionError is raised.
Thread.abort_on_exception = true
DEFAULT_PORT = 27017
STANDARD_HEADER_SIZE = 16
RESPONSE_HEADER_SIZE = 20
MONGODB_URI_MATCHER = /(([.\w\d]+):([\w\d]+)@)?([.\w\d]+)(:([\w\d]+))?(\/([-\d\w]+))?/
MONGODB_URI_SPEC = "mongodb://[username:password@]host1[:port1][,host2[:port2],...[,hostN[:portN]]][/database]"
attr_reader :logger, :size, :host, :port, :nodes, :auths, :sockets, :checked_out
# Counter for generating unique request ids.
@@current_request_id = 0
# Create a connection to MongoDB. Specify either one or a pair of servers,
# along with a maximum connection pool size and timeout.
#
# If connecting to just one server, you may specify whether connection to slave is permitted.
# In all cases, the default host is "localhost" and the default port is 27017.
#
# To specify a pair, use Connection.paired.
#
# Note that there are a few issues when using connection pooling with Ruby 1.9 on Windows. These
# should be resolved in the next release.
#
# @param [String, Hash] host.
# @param [Integer] port specify a port number here if only one host is being specified.
#
# @option options [Boolean] :slave_ok (false) Must be set to +true+ when connecting
# to a single, slave node.
# @option options [Logger, #debug] :logger (nil) Logger instance to receive driver operation log.
# @option options [Integer] :pool_size (1) The maximum number of socket connections that can be opened to the database.
# @option options [Float] :timeout (5.0) When all of the connections to the pool are checked out,
# this is the number of seconds to wait for a new connection to be released before throwing an exception.
#
# @example localhost, 27017
# Connection.new
#
# @example localhost, 27017
# Connection.new("localhost")
#
# @example localhost, 3000, max 5 connections, with max 5 seconds of wait time.
# Connection.new("localhost", 3000, :pool_size => 5, :timeout => 5)
#
# @example localhost, 3000, where this node may be a slave
# Connection.new("localhost", 3000, :slave_ok => true)
#
# @see http://www.mongodb.org/display/DOCS/Replica+Pairs+in+Ruby Replica pairs in Ruby
#
# @core connections
def initialize(host=nil, port=nil, options={})
@auths = []
if block_given?
@nodes = yield self
else
@nodes = format_pair(host, port)
end
# Host and port of current master.
@host = @port = nil
# Lock for request ids.
@id_lock = Mutex.new
# Pool size and timeout.
@size = options[:pool_size] || 1
@timeout = options[:timeout] || 5.0
# Mutex for synchronizing pool access
@connection_mutex = Mutex.new
@safe_mutex = Mutex.new
# Condition variable for signal and wait
@queue = ConditionVariable.new
@sockets = []
@checked_out = []
# slave_ok can be true only if one node is specified
@slave_ok = options[:slave_ok] && @nodes.length == 1
@logger = options[:logger] || nil
@options = options
should_connect = options[:connect].nil? ? true : options[:connect]
connect_to_master if should_connect
end
# Initialize a paired connection to MongoDB.
#
# @param nodes [Array] An array of arrays, each of which specified a host and port.
# @param opts Takes the same options as Connection.new
#
# @example
# Connection.new([["db1.example.com", 27017],
# ["db2.example.com", 27017]])
#
# @example
# Connection.new([["db1.example.com", 27017],
# ["db2.example.com", 27017]],
# :pool_size => 20, :timeout => 5)
#
# @return [Mongo::Connection]
def self.paired(nodes, opts={})
unless nodes.length == 2 && nodes.all? {|n| n.is_a? Array}
raise MongoArgumentError, "Connection.paired requires that exactly two nodes be specified."
end
# Block returns an array, the first element being an array of nodes and the second an array
# of authorizations for the database.
new(nil, nil, opts) do |con|
[con.pair_val_to_connection(nodes[0]), con.pair_val_to_connection(nodes[1])]
end
end
# Initialize a connection to MongoDB using the MongoDB URI spec:
#
# @param uri [String]
# A string of the format mongodb://[username:password@]host1[:port1][,host2[:port2],...[,hostN[:portN]]][/database]
#
# @param opts Any of the options available for Connection.new
#
# @return [Mongo::Connection]
def self.from_uri(uri, opts={})
new(nil, nil, opts) do |con|
con.parse_uri(uri)
end
end
# Apply each of the saved database authentications.
#
# @return [Boolean] returns true if authentications exist and succeeed, false
# if none exists.
#
# @raise [AuthenticationError] raises an exception if any one
# authentication fails.
def apply_saved_authentication
return false if @auths.empty?
@auths.each do |auth|
self[auth['db_name']].authenticate(auth['username'], auth['password'], false)
end
true
end
# Save an authentication to this connection. When connecting,
# the connection will attempt to re-authenticate on every db
# specificed in the list of auths. This method is called automatically
# by DB#authenticate.
#
# @param [String] db_name
# @param [String] username
# @param [String] password
#
# @return [Hash] a hash representing the authentication just added.
def add_auth(db_name, username, password)
remove_auth(db_name)
auth = {}
auth['db_name'] = db_name
auth['username'] = username
auth['password'] = password
@auths << auth
auth
end
# Remove a saved authentication for this connection.
#
# @param [String] db_name
#
# @return [Boolean]
def remove_auth(db_name)
return unless @auths
if @auths.reject! { |a| a['db_name'] == db_name }
true
else
false
end
end
# Remove all authenication information stored in this connection.
#
# @return [true] this operation return true because it always succeeds.
def clear_auths
@auths = []
true
end
# Return a hash with all database names
# and their respective sizes on disk.
#
# @return [Hash]
def database_info
doc = self['admin'].command({:listDatabases => 1}, false, true)
returning({}) do |info|
doc['databases'].each { |db| info[db['name']] = db['sizeOnDisk'].to_i }
end
end
# Return an array of database names.
#
# @return [Array]
def database_names
database_info.keys
end
# Return a database with the given name.
# See DB#new for valid options hash parameters.
#
# @param [String] db_name a valid database name.
#
# @return [Mongo::DB]
#
# @core databases db-instance_method
def db(db_name, options={})
DB.new(db_name, self, options.merge(:logger => @logger))
end
# Shortcut for returning a database. Use DB#db to accept options.
#
# @param [String] db_name a valid database name.
#
# @return [Mongo::DB]
#
# @core databases []-instance_method
def [](db_name)
DB.new(db_name, self, :logger => @logger)
end
# Drop a database.
#
# @param [String] name name of an existing database.
def drop_database(name)
self[name].command(:dropDatabase => 1)
end
# Copy the database +from+ to +to+ on localhost. The +from+ database is
# assumed to be on localhost, but an alternate host can be specified.
#
# @param [String] from name of the database to copy from.
# @param [String] to name of the database to copy to.
# @param [String] from_host host of the 'from' database.
# @param [String] username username for authentication against from_db (>=1.3.x).
# @param [String] password password for authentication against from_db (>=1.3.x).
def copy_database(from, to, from_host="localhost", username=nil, password=nil)
oh = OrderedHash.new
oh[:copydb] = 1
oh[:fromhost] = from_host
oh[:fromdb] = from
oh[:todb] = to
if username || password
unless username && password
raise MongoArgumentError, "Both username and password must be supplied for authentication."
end
nonce_cmd = OrderedHash.new
nonce_cmd[:copydbgetnonce] = 1
nonce_cmd[:fromhost] = from_host
result = self["admin"].command(nonce_cmd, true, true)
oh[:nonce] = result["nonce"]
oh[:username] = username
oh[:key] = Mongo::Support.auth_key(username, password, oh[:nonce])
end
self["admin"].command(oh, true, true)
end
# Increment and return the next available request id.
#
# return [Integer]
def get_request_id
request_id = ''
@id_lock.synchronize do
request_id = @@current_request_id += 1
end
request_id
end
# Get the build information for the current connection.
#
# @return [Hash]
def server_info
self["admin"].command({:buildinfo => 1}, false, true)
end
# Get the build version of the current server.
#
# @return [Mongo::ServerVersion]
# object allowing easy comparability of version.
def server_version
ServerVersion.new(server_info["version"])
end
# Is it okay to connect to a slave?
#
# @return [Boolean]
def slave_ok?
@slave_ok
end
## Connections and pooling ##
# Send a message to MongoDB, adding the necessary headers.
#
# @param [Integer] operation a MongoDB opcode.
# @param [BSON::ByteBuffer] message a message to send to the database.
# @param [String] log_message text version of +message+ for logging.
#
# @return [True]
def send_message(operation, message, log_message=nil)
@logger.debug(" MONGODB #{log_message || message}") if @logger
begin
packed_message = add_message_headers(operation, message).to_s
socket = checkout
send_message_on_socket(packed_message, socket)
ensure
checkin(socket)
end
end
# Sends a message to the database, waits for a response, and raises
# an exception if the operation has failed.
#
# @param [Integer] operation a MongoDB opcode.
# @param [BSON::ByteBuffer] message a message to send to the database.
# @param [String] db_name the name of the database. used on call to get_last_error.
# @param [String] log_message text version of +message+ for logging.
#
# @return [Array]
# An array whose indexes include [0] documents returned, [1] number of document received,
# and [3] a cursor_id.
def send_message_with_safe_check(operation, message, db_name, log_message=nil)
message_with_headers = add_message_headers(operation, message)
message_with_check = last_error_message(db_name)
@logger.debug(" MONGODB #{log_message || message}") if @logger
begin
sock = checkout
packed_message = message_with_headers.append!(message_with_check).to_s
docs = num_received = cursor_id = ''
@safe_mutex.synchronize do
send_message_on_socket(packed_message, sock)
docs, num_received, cursor_id = receive(sock)
end
ensure
checkin(sock)
end
if num_received == 1 && error = docs[0]['err']
raise Mongo::OperationFailure, error
end
[docs, num_received, cursor_id]
end
# Sends a message to the database and waits for the response.
#
# @param [Integer] operation a MongoDB opcode.
# @param [BSON::ByteBuffer] message a message to send to the database.
# @param [String] log_message text version of +message+ for logging.
# @param [Socket] socket a socket to use in lieu of checking out a new one.
#
# @return [Array]
# An array whose indexes include [0] documents returned, [1] number of document received,
# and [3] a cursor_id.
def receive_message(operation, message, log_message=nil, socket=nil)
packed_message = add_message_headers(operation, message).to_s
@logger.debug(" MONGODB #{log_message || message}") if @logger
begin
sock = socket || checkout
result = ''
@safe_mutex.synchronize do
send_message_on_socket(packed_message, sock)
result = receive(sock)
end
ensure
checkin(sock)
end
result
end
# Create a new socket and attempt to connect to master.
# If successful, sets host and port to master and returns the socket.
#
# @raise [ConnectionFailure] if unable to connect to any host or port.
def connect_to_master
close
@host = @port = nil
for node_pair in @nodes
host, port = *node_pair
begin
socket = TCPSocket.new(host, port)
socket.setsockopt(Socket::IPPROTO_TCP, Socket::TCP_NODELAY, 1)
# If we're connected to master, set the @host and @port
result = self['admin'].command({:ismaster => 1}, false, false, socket)
if result['ok'] == 1 && ((is_master = result['ismaster'] == 1) || @slave_ok)
@host, @port = host, port
apply_saved_authentication
end
# Note: slave_ok can be true only when connecting to a single node.
if @nodes.length == 1 && !is_master && !@slave_ok
raise ConfigurationError, "Trying to connect directly to slave; " +
"if this is what you want, specify :slave_ok => true."
end
break if is_master || @slave_ok
rescue SocketError, SystemCallError, IOError => ex
socket.close if socket
close
false
end
end
raise ConnectionFailure, "failed to connect to any given host:port" unless socket
end
# Are we connected to MongoDB? This is determined by checking whether
# host and port have values, since they're set to nil on calls to #close.
def connected?
@host && @port
end
# Close the connection to the database.
def close
@sockets.each do |sock|
sock.close
end
@host = @port = nil
@sockets.clear
@checked_out.clear
end
## Configuration helper methods
# Returns an array of host-port pairs.
#
# @private
def format_pair(pair_or_host, port)
case pair_or_host
when String
[[pair_or_host, port ? port.to_i : DEFAULT_PORT]]
when nil
[['localhost', DEFAULT_PORT]]
end
end
# Convert an argument containing a host name string and a
# port number integer into a [host, port] pair array.
#
# @private
def pair_val_to_connection(a)
case a
when nil
['localhost', DEFAULT_PORT]
when String
[a, DEFAULT_PORT]
when Integer
['localhost', a]
when Array
a
end
end
# Parse a MongoDB URI. This method is used by Connection.from_uri.
# Returns an array of nodes and an array of db authorizations, if applicable.
#
# @private
def parse_uri(string)
if string =~ /^mongodb:\/\//
string = string[10..-1]
else
raise MongoArgumentError, "MongoDB URI must match this spec: #{MONGODB_URI_SPEC}"
end
nodes = []
auths = []
specs = string.split(',')
specs.each do |spec|
matches = MONGODB_URI_MATCHER.match(spec)
if !matches
raise MongoArgumentError, "MongoDB URI must match this spec: #{MONGODB_URI_SPEC}"
end
uname = matches[2]
pwd = matches[3]
host = matches[4]
port = matches[6] || DEFAULT_PORT
if !(port.to_s =~ /^\d+$/)
raise MongoArgumentError, "Invalid port #{port}; port must be specified as digits."
end
port = port.to_i
db = matches[8]
if (uname || pwd || db) && !(uname && pwd && db)
raise MongoArgumentError, "MongoDB URI must include all three of username, password, " +
"and db if any one of these is specified."
else
add_auth(db, uname, pwd)
end
nodes << [host, port]
end
nodes
end
private
# 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