Class: SocketPool

Inherits:
Object
  • Object
show all
Defined in:
lib/socketpool.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

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

Create a new socket pool



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# File 'lib/socketpool.rb', line 23

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

  # Pool size and timeout.
  @size      = opts[:size] || 2
  @timeout   = opts[:timeout] || 5
  @eager      = opts[:eager] || false

  # Mutex for synchronizing pool access
  @connection_mutex = Mutex.new

  # Condition variable for signal and wait
  @queue = ConditionVariable.new
  
  @socktype     = opts[:type] || :tcp
  @sockopts     = opts[:socketopts].nil? ? [] : [opts[:socketopts]].flatten.inject([]){|s, so| s << so}
  @sockets      = []
  @pids         = {}
  @checked_out  = []
  
  initialize_socketpool if @eager
end

Instance Attribute Details

#checked_out ⇒ Object

Returns the value of attribute checked_out.



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# File 'lib/socketpool.rb', line 19

def checked_out
  @checked_out
end

#host ⇒ Object

Returns the value of attribute host.



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# File 'lib/socketpool.rb', line 19

def host
  @host
end

#port ⇒ Object

Returns the value of attribute port.



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# File 'lib/socketpool.rb', line 19

def port
  @port
end

#size ⇒ Object

Returns the value of attribute size.



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# File 'lib/socketpool.rb', line 19

def size
  @size
end

#timeout ⇒ Object

Returns the value of attribute timeout.



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# File 'lib/socketpool.rb', line 19

def timeout
  @timeout
end

Instance Method Details

#checkin(sock, reset = false) ⇒ Object

Return a socket to the pool. Allow for destroying a resetting socket if the application determines the connection is no good



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# File 'lib/socketpool.rb', line 62

def checkin(sock, reset=false)
  @connection_mutex.synchronize do
    if reset
      @sockets.delete(sock)
      @checked_out.delete(sock)
      @pids.delete(sock)
      sock.close
      sock = checkout_new_socket
    end

    @checked_out.delete(sock)          
    @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/socketpool.rb', line 117

def checkout
  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
        return socket
      else
        # Otherwise, wait
        @queue.wait(@connection_mutex)
      end
    end
  end
end

#checkout_existing_socket ⇒ 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/socketpool.rb', line 101

def checkout_existing_socket
  socket = (@sockets - @checked_out).first
  if @pids[socket] != Process.pid
     @pids[socket] = nil
     @sockets.delete(socket)
     socket.close
     checkout_new_socket
  else
    @checked_out << socket
    socket
  end
end

#checkout_new_socket ⇒ Object

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



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# File 'lib/socketpool.rb', line 79

def checkout_new_socket
  socket = Socket.new(so_domain(@socktype), so_type(@socktype), 0)

  # Pack address for sockets and set any options passed
  @sockaddr ||= Socket.pack_sockaddr_in(@port, @host) if ![:unix, :unigram].include?(@socktype)
  @sockaddr ||= Socket.pack_sockaddr_un(@host) if [:unix, :unigram].include?(@socktype)
  @sockopts.each{ |opt| socket.setsockopt(opt[:level], opt[:optname], opt[:optval]) } if @sockopts.size > 0 
  socket.connect(@sockaddr)

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

#close ⇒ Object 



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# File 'lib/socketpool.rb', line 46

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

#so_domain(val) ⇒ Object 



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# File 'lib/socketpool.rb', line 155

def so_domain(val)
  val = val.downcase.to_sym if val.respond_to?(:downcase) && val.respond_to?(:to_sym)
  @so_domain ||= {
    :tcp => Socket::AF_INET,
    :tcp6 => Socket::AF_INET6,
    :udp => Socket::AF_INET,
    :udp6 => Socket::AF_INET6,
    :unix => Socket::AF_UNIX,
    :unigram => Socket::AF_UNIX
  }[val]
end

#so_type(val) ⇒ Object 



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# File 'lib/socketpool.rb', line 143

def so_type(val)
  val = val.downcase.to_sym if val.respond_to?(:downcase) && val.respond_to?(:to_sym)
  @so_type ||= {
    :tcp => Socket::SOCK_STREAM,
    :tcp6 => Socket::SOCK_STREAM,
    :udp => Socket::SOCK_DGRAM,
    :udp6 => Socket::SOCK_DGRAM,
    :unix => Socket::SOCK_STREAM,
    :unigram => Socket::SOCK_DGRAM
  }[val]
end