Class: Mongo::Pool

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

Constant Summary collapse

PING_ATTEMPTS = 
6
MAX_PING_TIME = 
1_000_000
PRUNE_INTERVAL = 
10_000

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

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

Create a new pool of connections.



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# File 'lib/mongo/util/pool.rb', line 33

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

  @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

  # Mutex for synchronizing pings
  @ping_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

Instance Attribute Details

#address ⇒ Object

Returns the value of attribute address.



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# File 'lib/mongo/util/pool.rb', line 24

def address
  @address
end

#checked_out ⇒ Object

Returns the value of attribute checked_out.



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# File 'lib/mongo/util/pool.rb', line 24

def checked_out
  @checked_out
end

#client ⇒ Object

Returns the value of attribute client.



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# File 'lib/mongo/util/pool.rb', line 24

def client
  @client
end

#host ⇒ Object

Returns the value of attribute host.



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# File 'lib/mongo/util/pool.rb', line 24

def host
  @host
end

#port ⇒ Object

Returns the value of attribute port.



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# File 'lib/mongo/util/pool.rb', line 24

def port
  @port
end

#size ⇒ Object

Returns the value of attribute size.



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# File 'lib/mongo/util/pool.rb', line 24

def size
  @size
end

#timeout ⇒ Object

Returns the value of attribute timeout.



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# File 'lib/mongo/util/pool.rb', line 24

def timeout
  @timeout
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 218

def authenticate_existing
  @connection_mutex.synchronize do
    @sockets.each do |socket|
      @socket_ops[socket] << Proc.new do
        @client.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 178

def checkin(socket)
  @connection_mutex.synchronize do
    if @checked_out.delete(socket)
      @queue.signal
    else
      return false
    end
  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 277

def checkout
  @client.connect if !@client.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) ⇒ Object

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.



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# File 'lib/mongo/util/pool.rb', line 247

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 ⇒ 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 193

def checkout_new_socket
  begin
    socket = @client.socket_class.new(@host, @port, @client.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.
  @client.apply_saved_authentication(:socket => socket)

  @sockets << socket
  @pids[socket] = Process.pid
  @checked_out << socket
  @threads_to_sockets[Thread.current] = socket
  socket
end

#close(opts = {}) ⇒ Object

Close this pool.

Options Hash (opts):

  • :soft (Boolean) — default: false —

    If true, close only those sockets that are not checked out.



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# File 'lib/mongo/util/pool.rb', line 74

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
    @node.close if @node
  end
  true
end

#closed? ⇒ Boolean 



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# File 'lib/mongo/util/pool.rb', line 92

def closed?
  @closed
end

#host_port ⇒ Object 



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

def host_port
  [@host, @port]
end

#host_string ⇒ Object 



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# File 'lib/mongo/util/pool.rb', line 125

def host_string
  "#{@host}:#{@port}"
end

#inspect ⇒ Object 



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# File 'lib/mongo/util/pool.rb', line 119

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 " +
    "up=#{!closed?}>"
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 230

def logout_existing(db)
  @connection_mutex.synchronize do
    @sockets.each do |socket|
      @socket_ops[socket] << Proc.new do
        @client.db(db).issue_logout(:socket => socket)
      end
    end
  end
end

#matches_mode(mode) ⇒ Object 



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# File 'lib/mongo/util/pool.rb', line 100

def matches_mode(mode)
  if mode == :primary && @node.secondary? ||
    mode == :secondary && @node.primary?
    false
  else
    true
  end
end

#matches_tag_set(tag_set) ⇒ Object 



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# File 'lib/mongo/util/pool.rb', line 109

def matches_tag_set(tag_set)
  tag_set.all? do |tag, value|
    tags.has_key?(tag) && tags[tag] == value
  end
end

#matches_tag_sets(tag_sets) ⇒ Object 



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

def matches_tag_sets(tag_sets)
  tag_sets.all? {|set| matches_tag_set(set)}
end

#ping ⇒ Object 



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# File 'lib/mongo/util/pool.rb', line 169

def ping
  begin
    return self.client['admin'].command({:ping => 1}, :socket => @node.socket, :timeout => MAX_PING_TIME)
  rescue ConnectionFailure, OperationFailure, SocketError, SystemCallError, IOError
    return false
  end
end

#ping_time ⇒ Object

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



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# File 'lib/mongo/util/pool.rb', line 135

def ping_time
  @ping_mutex.synchronize do
    if !@last_ping || (Time.now - @last_ping) > 300
      @ping_time = refresh_ping_time
      @last_ping = Time.now
    end
  end
  @ping_time
end

#prune_thread_socket_hash ⇒ Object 



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# File 'lib/mongo/util/pool.rb', line 266

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 ⇒ Object

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



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# File 'lib/mongo/util/pool.rb', line 147

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

#tags ⇒ Object 



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# File 'lib/mongo/util/pool.rb', line 88

def tags
  @node.tags
end

#up? ⇒ Boolean 



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# File 'lib/mongo/util/pool.rb', line 96

def up?
  !@closed
end