Class: MemCache::Server

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

Overview

This class represents a memcached server instance.

Constant Summary collapse

CONNECT_TIMEOUT =

The amount of time to wait to establish a connection with a memcached server. If a connection cannot be established within this time limit, the server will be marked as down.

0.25
RETRY_DELAY =

The amount of time to wait before attempting to re-establish a connection with a server that is marked dead.

30.0

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(memcache, host, port = DEFAULT_PORT, weight = DEFAULT_WEIGHT) ⇒ Server

Create a new MemCache::Server object for the memcached instance listening on the given host and port, weighted by the given weight.

Raises:

  • (ArgumentError) 


618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
 
# File 'lib/memcache.rb', line 618

def initialize(memcache, host, port = DEFAULT_PORT, weight = DEFAULT_WEIGHT)
  raise ArgumentError, "No host specified" if host.nil? or host.empty?
  raise ArgumentError, "No port specified" if port.nil? or port.to_i.zero?

  @memcache = memcache
  @host   = host
  @port   = port.to_i
  @weight = weight.to_i

  @multithread = @memcache.multithread
  @mutex = Mutex.new

  @sock   = nil
  @retry  = nil
  @status = 'NOT CONNECTED'
end

Instance Attribute Details

#host ⇒ Object (readonly)

The host the memcached server is running on.



592
593
594
 
# File 'lib/memcache.rb', line 592

def host
  @host
end

#port ⇒ Object (readonly)

The port the memcached server is listening on.



597
598
599
 
# File 'lib/memcache.rb', line 597

def port
  @port
end

#retry ⇒ Object (readonly)

The time of next retry if the connection is dead.



607
608
609
 
# File 'lib/memcache.rb', line 607

def retry
  @retry
end

#status ⇒ Object (readonly)

A text status string describing the state of the server.



612
613
614
 
# File 'lib/memcache.rb', line 612

def status
  @status
end

#weight ⇒ Object (readonly)

The weight given to the server.



602
603
604
 
# File 'lib/memcache.rb', line 602

def weight
  @weight
end

Instance Method Details

#alive? ⇒ Boolean

Check whether the server connection is alive. This will cause the socket to attempt to connect if it isn’t already connected and or if the server was previously marked as down and the retry time has been exceeded.

Returns:

  • (Boolean) 


648
649
650
 
# File 'lib/memcache.rb', line 648

def alive?
  !!socket
end

#close ⇒ Object

Close the connection to the memcached server targeted by this object. The server is not considered dead.



685
686
687
688
689
690
691
692
693
 
# File 'lib/memcache.rb', line 685

def close
  @mutex.lock if @multithread
  @sock.close if @sock && !@sock.closed?
  @sock   = nil
  @retry  = nil
  @status = "NOT CONNECTED"
ensure
  @mutex.unlock if @multithread
end

#inspect ⇒ Object

Return a string representation of the server object.



638
639
640
 
# File 'lib/memcache.rb', line 638

def inspect
  "<MemCache::Server: %s:%d [%d] (%s)>" % [@host, @port, @weight, @status]
end

#socket ⇒ Object

Try to connect to the memcached server targeted by this object. Returns the connected socket object on success or nil on failure.



656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
 
# File 'lib/memcache.rb', line 656

def socket
  @mutex.lock if @multithread
  return @sock if @sock and not @sock.closed?

  @sock = nil

  # If the host was dead, don't retry for a while.
  return if @retry and @retry > Time.now

  # Attempt to connect if not already connected.
  begin
    @sock = timeout CONNECT_TIMEOUT do
      TCPSocket.new @host, @port
    end
    @retry  = nil
    @status = 'CONNECTED'
  rescue SocketError, SystemCallError, IOError, Timeout::Error => err
    mark_dead err.message
  end

  return @sock
ensure
  @mutex.unlock if @multithread
end