mongo-ruby-driver/lib/mongo/util/pool.rb
2012-02-27 16:16:09 -05:00

304 lines
8.4 KiB
Ruby

# encoding: UTF-8
# --
# Copyright (C) 2008-2011 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.
module Mongo
class Pool
PING_ATTEMPTS = 6
MAX_PING_TIME = 1_000_000
PRUNE_INTERVAL = 1000
attr_accessor :host, :port, :address,
:size, :timeout, :safe, :checked_out, :connection
# Create a new pool of connections.
def initialize(connection, host, port, opts={})
@connection = connection
@host, @port = host, port
# A Mongo::Node object.
@node = opts[:node]
# The string address
@address = "#{@host}:#{@port}"
# Pool size and timeout.
@size = opts.fetch(:size, 20)
@timeout = opts.fetch(:timeout, 30)
# Mutex for synchronizing pool access
@connection_mutex = Mutex.new
# Condition variable for signal and wait
@queue = ConditionVariable.new
# Operations to perform on a socket
@socket_ops = Hash.new { |h, k| h[k] = [] }
@sockets = []
@pids = {}
@checked_out = []
@ping_time = nil
@last_ping = nil
@closed = false
@threads_to_sockets = {}
@checkout_counter = 0
end
# Close this pool.
#
# @option opts [Boolean] :soft (false) If true,
# close only those sockets that are not checked out.
def close(opts={})
@connection_mutex.synchronize do
if opts[:soft]
sockets_to_close = @sockets - @checked_out
else
sockets_to_close = @sockets
end
sockets_to_close.each do |sock|
begin
sock.close unless sock.closed?
rescue IOError => ex
warn "IOError when attempting to close socket connected to #{@host}:#{@port}: #{ex.inspect}"
end
end
@sockets.clear
@pids.clear
@checked_out.clear
@closed = true
end
end
def closed?
@closed
end
def inspect
"#<Mongo::Pool:0x#{self.object_id.to_s(16)} @host=#{@host} @port=#{port} " +
"@ping_time=#{@ping_time} #{@checked_out.size}/#{@size} sockets available.>"
end
def host_string
"#{@host}:#{@port}"
end
def host_port
[@host, @port]
end
# Refresh ping time only if we haven't
# checked within the last five minutes.
def ping_time
if !@last_ping
@last_ping = Time.now
@ping_time = refresh_ping_time
elsif Time.now - @last_ping > 300
@last_ping = Time.now
@ping_time = refresh_ping_time
else
@ping_time
end
end
# Return the time it takes on average
# to do a round-trip against this node.
def refresh_ping_time
trials = []
PING_ATTEMPTS.times do
t1 = Time.now
if !self.ping
return MAX_PING_TIME
end
trials << (Time.now - t1) * 1000
end
trials.sort!
# Delete shortest and longest times
trials.delete_at(trials.length-1)
trials.delete_at(0)
total = 0.0
trials.each { |t| total += t }
(total / trials.length).ceil
end
def ping
begin
return self.connection['admin'].command({:ping => 1}, :socket => @node.socket)
rescue OperationFailure, SocketError, SystemCallError, IOError => ex
return false
end
end
# Return a socket to the pool.
def checkin(socket)
@connection_mutex.synchronize do
if @checked_out.delete(socket)
@queue.signal
else
return false
end
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 = self.connection.socket_class.new(@host, @port)
socket.setsockopt(Socket::IPPROTO_TCP, Socket::TCP_NODELAY, 1)
rescue => ex
socket.close if socket
raise ConnectionFailure, "Failed to connect to host #{@host} and port #{@port}: #{ex}"
@node.close if @node
end
# If any saved authentications exist, we want to apply those
# when creating new sockets.
@connection.apply_saved_authentication(:socket => socket)
@sockets << socket
@pids[socket] = Process.pid
@checked_out << socket
@threads_to_sockets[Thread.current] = socket
socket
end
# If a user calls DB#authenticate, and several sockets exist,
# then we need a way to apply the authentication on each socket.
# So we store the apply_authentication method, and this will be
# applied right before the next use of each socket.
def authenticate_existing
@connection_mutex.synchronize do
@sockets.each do |socket|
@socket_ops[socket] << Proc.new do
@connection.apply_saved_authentication(:socket => socket)
end
end
end
end
# Store the logout op for each existing socket to be applied before
# the next use of each socket.
def logout_existing(db)
@connection_mutex.synchronize do
@sockets.each do |socket|
@socket_ops[socket] << Proc.new do
@connection.db(db).issue_logout(:socket => socket)
end
end
end
end
# Checks out the first available socket from the pool.
#
# If the pid has changed, remove the socket and check out
# new one.
#
# This method is called exclusively from #checkout;
# therefore, it runs within a mutex.
def checkout_existing_socket(socket=nil)
if !socket
socket = (@sockets - @checked_out).first
end
if @pids[socket] != Process.pid
@pids[socket] = nil
@sockets.delete(socket)
socket.close if socket
checkout_new_socket
else
@checked_out << socket
@threads_to_sockets[Thread.current] = socket
socket
end
end
def prune_thread_socket_hash
map = {}
Thread.list.each do |t|
map[t] = 1
end
@threads_to_sockets.keys.each do |key|
if !map[key]
@threads_to_sockets.delete(key)
end
end
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
@connection.connect if !@connection.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
if @checkout_counter > PRUNE_INTERVAL
@checkout_counter = 0
prune_thread_socket_hash
else
@checkout_counter += 1
end
if socket_for_thread = @threads_to_sockets[Thread.current]
if !@checked_out.include?(socket_for_thread)
socket = checkout_existing_socket(socket_for_thread)
end
else # First checkout for this thread
thread_length = @threads_to_sockets.keys.length
if (thread_length <= @sockets.size) && (@sockets.size < @size)
socket = checkout_new_socket
elsif @checked_out.size < @sockets.size
socket = checkout_existing_socket
elsif @sockets.size < @size
socket = checkout_new_socket
end
end
if socket
# This calls all procs, in order, scoped to existing sockets.
# At the moment, we use this to lazily authenticate and
# logout existing socket connections.
@socket_ops[socket].reject! do |op|
op.call
end
return socket
else
# Otherwise, wait
@queue.wait(@connection_mutex)
end
end
end
end
end
end