Class: Mongo::Pool

Inherits:
Object show all
Defined in:
lib/mongo/util/pool.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(connection, host, port, opts = {}) ⇒ Pool

Create a new pool of connections.



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# File 'lib/mongo/util/pool.rb', line 25

def initialize(connection, host, port, opts={})
  @connection  = connection

  @host, @port = host, port

  unless @port
    @unix_socket_path = host
    @host = nil
  end

  # Pool size and timeout.
  @size      = opts[:size] || 1
  @timeout   = opts[:timeout]   || 5.0

  # 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      = []
  @checked_out  = []
end

Instance Attribute Details

#checked_out ⇒ Object

Returns the value of attribute checked_out.



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# File 'lib/mongo/util/pool.rb', line 21

def checked_out
  @checked_out
end

#host ⇒ Object

Returns the value of attribute host.



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# File 'lib/mongo/util/pool.rb', line 21

def host
  @host
end

#port ⇒ Object

Returns the value of attribute port.



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# File 'lib/mongo/util/pool.rb', line 21

def port
  @port
end

#safe ⇒ Object

Returns the value of attribute safe.



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# File 'lib/mongo/util/pool.rb', line 21

def safe
  @safe
end

#size ⇒ Object

Returns the value of attribute size.



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# File 'lib/mongo/util/pool.rb', line 21

def size
  @size
end

#timeout ⇒ Object

Returns the value of attribute timeout.



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# File 'lib/mongo/util/pool.rb', line 21

def timeout
  @timeout
end

#unix_socket_path ⇒ Object

Returns the value of attribute unix_socket_path.



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# File 'lib/mongo/util/pool.rb', line 21

def unix_socket_path
  @unix_socket_path
end

Instance Method Details

#authenticate_existing ⇒ Object

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.



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# File 'lib/mongo/util/pool.rb', line 103

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) ⇒ Object

Return a socket to the pool.



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# File 'lib/mongo/util/pool.rb', line 66

def checkin(socket)
  @connection_mutex.synchronize do
    @checked_out.delete(socket)
    @queue.signal
  end
  true
end

#checkout ⇒ Object

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.



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# File 'lib/mongo/util/pool.rb', line 138

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
      socket = if @checked_out.size < @sockets.size
                 checkout_existing_socket
               elsif @sockets.size < @size
                 checkout_new_socket
               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
        if @logger
          @logger.warn "MONGODB Waiting for available connection; " +
            "#{@checked_out.size} of #{@size} connections checked out."
        end
        @queue.wait(@connection_mutex)
      end
    end
  end
end

#checkout_existing_socket ⇒ Object

Checks out the first available socket from the pool.

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



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# File 'lib/mongo/util/pool.rb', line 129

def checkout_existing_socket
  socket = (@sockets - @checked_out).first
  @checked_out << socket
  socket
end

#checkout_new_socket ⇒ Object

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

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



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# File 'lib/mongo/util/pool.rb', line 78

def checkout_new_socket
  begin
    if @unix_socket_path
      socket = UNIXSocket.new(@unix_socket_path)
    else
      socket = TCPSocket.new(@host, @port)
      socket.setsockopt(Socket::IPPROTO_TCP, Socket::TCP_NODELAY, 1)
    end
  rescue => ex
    raise ConnectionFailure, "Failed to connect to #{self.to_s}: #{ex}"
  end

  # If any saved authentications exist, we want to apply those
  # when creating new sockets.
  @connection.apply_saved_authentication(:socket => socket)

  @sockets << socket
  @checked_out << socket
  socket
end

#close ⇒ Object 



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# File 'lib/mongo/util/pool.rb', line 52

def close
  @sockets.each do |sock|
    begin
      sock.close
    rescue IOError => ex
      warn "IOError when attempting to close socket connected to #{self.to_s}: #{ex.inspect}"
    end
  end
  @host = @port = @unix_socket_path = nil
  @sockets.clear
  @checked_out.clear
end

#logout_existing(db) ⇒ Object

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



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# File 'lib/mongo/util/pool.rb', line 115

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

#to_s ⇒ Object 



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# File 'lib/mongo/util/pool.rb', line 177

def to_s
  if @unix_socket_path
    "#{@unix_socket_path}"
  else
    "#{@host}:#{@port}"
  end
end