class Mongo::Pool

Constants

MAX_PING_TIME
PING_ATTEMPTS
PRUNE_INTERVAL

Attributes

address[RW]
checked_out[RW]
connection[RW]
host[RW]
port[RW]
safe[RW]
size[RW]
timeout[RW]

Public Class Methods

new(connection, host, port, opts={}) click to toggle source

Create a new pool of connections.

# File lib/mongo/util/pool.rb, line 27
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

Public Instance Methods

authenticate_existing() click to toggle source

If a user calls Mongo::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.

# File lib/mongo/util/pool.rb, line 181
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
checkin(socket) click to toggle source

Return a socket to the pool.

# File lib/mongo/util/pool.rb, line 141
def checkin(socket)
  @connection_mutex.synchronize do
    if @checked_out.delete(socket)
      @queue.signal
    else
      return false
    end
  end
  true
end
checkout() click to toggle source

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.

# File lib/mongo/util/pool.rb, line 240
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

        if socket.closed?
          @checked_out.delete(socket)
          @sockets.delete(socket)
          @threads_to_sockets.each do |k,v|
            if v == socket
              @threads_to_sockets.delete(k)
            end
          end

          socket = checkout_new_socket
        end
        
        return socket
      else
        # Otherwise, wait
        @queue.wait(@connection_mutex)
      end
    end
  end
end
checkout_existing_socket(socket=nil) click to toggle source

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.

# File lib/mongo/util/pool.rb, line 210
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)
    if socket
      socket.close unless socket.closed?
    end
    checkout_new_socket
  else
    @checked_out << socket
    @threads_to_sockets[Thread.current] = socket
    socket
  end
end
checkout_new_socket() click to toggle source

Adds a new socket to the pool and checks it out.

This method is called exclusively from checkout; therefore, it runs within a mutex.

# File lib/mongo/util/pool.rb, line 156
def checkout_new_socket
  begin
    socket = @connection.socket_class.new(@host, @port, @connection.op_timeout)
    socket.pool = self
  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
close(opts={}) click to toggle source

Close this pool.

@option opts [Boolean] :soft (false) If true,

close only those sockets that are not checked out.
# File lib/mongo/util/pool.rb, line 65
def close(opts={})
  @connection_mutex.synchronize do
    if opts[:soft] && !@checked_out.empty?
      @closing = true
      close_sockets(@sockets - @checked_out)
    else
      close_sockets(@sockets)
      @closed = true
    end
  end
end
closed?() click to toggle source
# File lib/mongo/util/pool.rb, line 77
def closed?
  @closed
end
host_port() click to toggle source
# File lib/mongo/util/pool.rb, line 90
def host_port
  [@host, @port]
end
host_string() click to toggle source
# File lib/mongo/util/pool.rb, line 86
def host_string
  "#{@host}:#{@port}"
end
inspect() click to toggle source
# File lib/mongo/util/pool.rb, line 81
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
logout_existing(db) click to toggle source

Store the logout op for each existing socket to be applied before the next use of each socket.

# File lib/mongo/util/pool.rb, line 193
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
ping() click to toggle source
# File lib/mongo/util/pool.rb, line 132
def ping
  begin
    return self.connection['admin'].command({:ping => 1}, :socket => @node.socket)
  rescue OperationFailure, SocketError, SystemCallError, IOError
    return false
  end
end
ping_time() click to toggle source

Refresh ping time only if we haven't checked within the last five minutes.

# File lib/mongo/util/pool.rb, line 96
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
prune_thread_socket_hash() click to toggle source
# File lib/mongo/util/pool.rb, line 229
def prune_thread_socket_hash
  current_threads = Set[*Thread.list]

  @threads_to_sockets.delete_if do |thread, socket|
    !current_threads.include?(thread)
  end
end
refresh_ping_time() click to toggle source

Return the time it takes on average to do a round-trip against this node.

# File lib/mongo/util/pool.rb, line 110
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