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

134 lines
4.8 KiB
Ruby

# --
# Copyright (C) 2008-2009 10gen Inc.
#
# This program is free software: you can redistribute it and/or modify it
# under the terms of the GNU Affero General Public License, version 3, as
# published by the Free Software Foundation.
#
# This program is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
# FITNESS FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License
# for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
# ++
require 'mongo/db'
module XGen
module Mongo
module Driver
# Represents a Mongo database server.
class Mongo
DEFAULT_PORT = 27017
# Create a Mongo database server instance. You specify either one or a
# pair of servers. If one, you also say if connecting to a slave is
# OK. The host default is "localhost" and port default is
# DEFAULT_PORT. If you specify a pair, pair_or_host is an array of two
# arrays, where each is a host/port pair (or a host with no port), and
# the +port+ argument is ignored.
#
# Options are passed on to each DB instance:
#
# :slave_ok :: Only used if one host is specified. If false, when
# connecting to that host/port a DB object will check to
# see if the server is the master. If it is not, an error
# is thrown.
#
# :auto_reconnect :: If a DB connection gets closed (for example, we
# have a server pair and saw the "not master"
# error, which closes the connection), then
# automatically try to reconnect to the master or
# to the single server we have been given. Defaults
# to +false+.
#
# Since that's so confusing, here are a few examples:
#
# Mongo.new # localhost, DEFAULT_PORT, !slave
# Mongo.new("localhost") # localhost, DEFAULT_PORT, !slave
# Mongo.new("localhost", 3000) # localhost, 3000, slave not ok
# Mongo.new("localhost", 3000, :slave_ok => true) # localhost, 3000, slave ok
# # A pair of servers. DB will always talk to the master. On socket
# # error or "not master" error, we will auto-reconnect to the
# # current master.
# Mongo.new([["db1.example.com", 3000], ["db2.example.com", 3000]]], nil, :auto_reconnect => true)
#
# When a DB object first connects to a pair, it will find the master
# instance and connect to that one.
def initialize(pair_or_host=nil, port=nil, options={})
@pair = case pair_or_host
when String
[[pair_or_host, port || DEFAULT_PORT]]
when Array
pair_or_host.collect { |nh| [nh[0], nh[1] || DEFAULT_PORT] }
when nil
[['localhost', DEFAULT_PORT]]
end
@options = options
end
# Return the XGen::Mongo::Driver::DB named +db_name+. The slave_ok and
# auto_reconnect options passed in via #new may be overridden here.
# See DB#new for other options you can pass in.
def db(db_name, options={})
XGen::Mongo::Driver::DB.new(db_name, @pair, @options.merge(options))
end
# Returns a hash containing database names as keys and disk space for
# each as values.
def database_info
doc = single_db_command('admin', :listDatabases => 1)
h = {}
doc['databases'].each { |db|
h[db['name']] = db['sizeOnDisk'].to_i
}
h
end
# Returns an array of database names.
def database_names
database_info.keys
end
# Not implemented.
def clone_database(from)
raise "not implemented"
end
# Not implemented.
def copy_database(from_host, from_db, to_db)
raise "not implemented"
end
# Drops the database +name+.
def drop_database(name)
single_db_command(name, :dropDatabase => 1)
end
protected
# Send cmd (a hash, possibly ordered) to the admin database and return
# the answer. Raises an error unless the return is "ok" (DB#ok?
# returns +true+).
def single_db_command(db_name, cmd)
db = nil
begin
db = db(db_name)
doc = db.db_command(cmd)
raise "error retrieving database info: #{doc.inspect}" unless db.ok?(doc)
doc
ensure
db.close if db
end
end
end
end
end
end