def rotate_slaves(self):
"Round-robin slave balancer"
slaves = self.sentinel_manager.discover_slaves(self.service_name)
if slaves:
if self.slave_rr_counter is None:
self.slave_rr_counter = random.randint(0, len(slaves) - 1)
for _ in xrange(len(slaves)):
self.slave_rr_counter = (
self.slave_rr_counter + 1) % len(slaves)
slave = slaves[self.slave_rr_counter]
yield slave
# Fallback to the master connection
try:
yield self.get_master_address()
except MasterNotFoundError:
pass
raise SlaveNotFoundError('No slave found for %r' % (self.service_name))
def read_response(self):
response = self._buffer.readline()
if not response:
raise ConnectionError(SERVER_CLOSED_CONNECTION_ERROR)
byte, response = byte_to_chr(response[0]), response[1:]
if byte not in ('-', '+', ':', '$', '*'):
raise InvalidResponse("Protocol Error: %s, %s" %
(str(byte), str(response)))
# server returned an error
if byte == '-':
response = nativestr(response)
error = self.parse_error(response)
# if the error is a ConnectionError, raise immediately so the user
# is notified
if isinstance(error, ConnectionError):
raise error
# otherwise, we're dealing with a ResponseError that might belong
# inside a pipeline response. the connection's read_response()
# and/or the pipeline's execute() will raise this error if
# necessary, so just return the exception instance here.
return error
# single value
elif byte == '+':
pass
# int value
elif byte == ':':
response = long(response)
# bulk response
elif byte == '$':
length = int(response)
if length == -1:
return None
response = self._buffer.read(length)
# multi-bulk response
elif byte == '*':
length = int(response)
if length == -1:
return None
response = [self.read_response() for i in xrange(length)]
if isinstance(response, bytes) and self.encoding:
response = response.decode(self.encoding)
return response