def connect(self):
self.log.log(logging.TRACE, "Connecting to Memcache %s", self._address)
self._stream = BufferedStream(socket.create_connection(self._address))
class MemcacheConnection(object):
log = logging.getLogger("MemcacheConnection")
_read_timeout = 2
_write_timeout = 2
def __init__(self, address, protocol = "text", codec = "default"):
self._address = address
self._stream = None
self._read_queue = DeferredQueue()
self._write_queue = DeferredQueue()
self._protocol = MemcacheProtocol.create(protocol)
self._protocol.set_codec(MemcacheCodec.create(codec))
def connect(self):
self.log.log(logging.TRACE, "Connecting to Memcache %s", self._address)
self._stream = BufferedStream(socket.create_connection(self._address))
def disconnect(self):
if self._stream is None:
return
try:
self._stream.close()
except:
pass
self._stream = None
def is_connected(self):
return self._stream is not None
def flush(self):
self._stream.flush()
def _write_command(self, cmd, args, flush = True):
with self._stream.get_writer() as writer:
getattr(self._protocol, 'write_' + cmd)(writer, *args)
if flush:
writer.flush()
def _read_result(self, cmd):
with self._stream.get_reader() as reader:
return getattr(self._protocol, 'read_' + cmd)(reader)
def _defer_command(self, cmd, args, result_channel, error_value = None):
def _read_result():
timeout = Timeout(self._read_timeout, Timeout)
timeout.start()
try:
result = self._read_result(cmd)
result_channel.put(result)
except Timeout:
raise
except:
self.log.exception("read error in defer_command")
result_channel.put((MemcacheResult.ERROR, error_value))
self.log.warn("Error communicating with Memcache %s, disconnecting", self._address)
self.disconnect()
finally:
timeout.cancel()
def _write_command():
timeout = Timeout(self._write_timeout, Timeout)
timeout.start()
try:
if not self.is_connected():
self.connect()
self._write_command(cmd, args, True)
self._read_queue.defer(_read_result)
except Timeout:
raise
except:
result_channel.put((MemcacheResult.ERROR, error_value))
self.log.warn("Error communicating with Memcache %s, disconnecting", self._address)
self.disconnect()
finally:
timeout.cancel()
self._write_queue.defer(_write_command)
def _do_command(self, cmd, args, error_value = None):
result_channel = ResultChannel()
self._defer_command(cmd, args, result_channel, error_value)
try:
return result_channel.get()
except TimeoutError:
return MemcacheResult.TIMEOUT, error_value
def close(self):
if self.is_connected():
self._stream.close()
self._stream = None
def delete(self, key, expiration = 0):
return self._do_command("delete", (key, expiration))[0]
def set(self, key, data, expiration = 0, flags = 0):
return self._do_command("set", (key, data, expiration, flags))[0]
def __setitem__(self, key, data):
self.set(key, data)
def add(self, key, data, expiration = 0, flags = 0):
return self._do_command("add", (key, data, expiration, flags))[0]
def replace(self, key, data, expiration = 0, flags = 0):
return self._do_command("replace", (key, data, expiration, flags))[0]
def append(self, key, data, expiration = 0, flags = 0):
return self._do_command("append", (key, data, expiration, flags))[0]
def prepend(self, key, data, expiration = 0, flags = 0):
return self._do_command("prepend", (key, data, expiration, flags))[0]
def cas(self, key, data, cas_unique, expiration = 0, flags = 0):
return self._do_command("cas", (key, data, expiration, flags, cas_unique))[0]
def incr(self, key, delta = 1):
return self._do_command("incr", (key, delta))
def decr(self, key, delta = 1):
return self._do_command("decr", (key, delta))
def get(self, key, default = None):
_, values = self._do_command("get", ([key], ), {})
return values.get(key, default)
def __getitem__(self, key):
return self.get(key)
def getr(self, key, default = None):
result, values = self._do_command("get", ([key], ), {})
return result, values.get(key, default)
def gets(self, key, default = None):
result, values = self._do_command("gets", ([key], ), {})
value, cas_unique = values.get(key, (default, None))
return result, value, cas_unique
def get_multi(self, keys):
return self._do_command("get", (keys, ))
def gets_multi(self, keys):
return self._do_command("gets", (keys, ))
def version(self):
return self._do_command("version", ())
def stats(self):
return self._do_command("stats", ())
