class MemCache::Server

This class represents a memcached server instance.

Constants

RETRY_DELAY

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

Attributes

host[R]

The host the memcached server is running on.

logger[R]
port[R]

The port the memcached server is listening on.

retry[R]

The time of next retry if the connection is dead.

status[R]

A text status string describing the state of the server.

weight[R]

The weight given to the server.

Public Class Methods

new(memcache, host, port = DEFAULT_PORT, weight = DEFAULT_WEIGHT) click to toggle source

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

# File lib/memcache.rb, line 969
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?

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

  @sock   = nil
  @retry  = nil
  @status = 'NOT CONNECTED'
  @timeout = memcache.timeout
  @logger = memcache.logger
end

Public Instance Methods

alive?() click to toggle source

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.

# File lib/memcache.rb, line 997
def alive?
  !!socket
end
close() click to toggle source

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

# File lib/memcache.rb, line 1037
def close
  @sock.close if @sock && !@sock.closed?
  @sock   = nil
  @retry  = nil
  @status = "NOT CONNECTED"
end
connect_to(host, port, timeout=nil) click to toggle source
# File lib/memcache.rb, line 1027
def connect_to(host, port, timeout=nil)
  io = MemCache::BufferedIO.new(TCPSocket.new(host, port))
  io.read_timeout = timeout
  io
end
inspect() click to toggle source

Return a string representation of the server object.

# File lib/memcache.rb, line 987
def inspect
  "<MemCache::Server: %s:%d [%d] (%s)>" % [@host, @port, @weight, @status]
end
mark_dead(error) click to toggle source

Mark the server as dead and close its socket.

# File lib/memcache.rb, line 1047
def mark_dead(error)
  @sock.close if @sock && !@sock.closed?
  @sock   = nil
  @retry  = Time.now + RETRY_DELAY

  reason = "#{error.class.name}: #{error.message}"
  @status = sprintf "%s:%s DEAD (%s), will retry at %s", @host, @port, reason, @retry
  @logger.info { @status } if @logger
end
socket() click to toggle source

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

# File lib/memcache.rb, line 1005
def socket
  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 = connect_to(@host, @port, @timeout)
    @sock.setsockopt Socket::IPPROTO_TCP, Socket::TCP_NODELAY, 1
    @retry  = nil
    @status = 'CONNECTED'
  rescue SocketError, SystemCallError, IOError => err
    logger.warn { "Unable to open socket: #{err.class.name}, #{err.message}" } if logger
    mark_dead err
  end

  return @sock
end