def read_response(self):
if not self._reader:
raise ConnectionError(SERVER_CLOSED_CONNECTION_ERROR)
# _next_response might be cached from a can_read() call
if self._next_response is not False:
response = self._next_response
self._next_response = False
return response
response = self._reader.gets()
socket_read_size = self.socket_read_size
while response is False:
try:
if HIREDIS_USE_BYTE_BUFFER:
bufflen = self._sock.recv_into(self._buffer)
if bufflen == 0:
raise socket.error(SERVER_CLOSED_CONNECTION_ERROR)
else:
buffer = self._sock.recv(socket_read_size)
# an empty string indicates the server shutdown the socket
if not isinstance(buffer, bytes) or len(buffer) == 0:
raise socket.error(SERVER_CLOSED_CONNECTION_ERROR)
except socket.timeout:
raise TimeoutError("Timeout reading from socket")
except socket.error:
e = sys.exc_info()[1]
raise ConnectionError("Error while reading from socket: %s" %
(e.args,))
if HIREDIS_USE_BYTE_BUFFER:
self._reader.feed(self._buffer, 0, bufflen)
else:
self._reader.feed(buffer)
# proactively, but not conclusively, check if more data is in the
# buffer. if the data received doesn't end with \r\n, there's more.
if HIREDIS_USE_BYTE_BUFFER:
if bufflen > 2 and self._buffer[bufflen - 2:bufflen] != SYM_CRLF:
continue
else:
if not buffer.endswith(SYM_CRLF):
continue
response = self._reader.gets()
# if an older version of hiredis is installed, we need to attempt
# to convert ResponseErrors to their appropriate types.
if not HIREDIS_SUPPORTS_CALLABLE_ERRORS:
if isinstance(response, ResponseError):
response = self.parse_error(response.args[0])
elif isinstance(response, list) and response and \
isinstance(response[0], ResponseError):
response[0] = self.parse_error(response[0].args[0])
# if the response is a ConnectionError or the response is a list and
# the first item is a ConnectionError, raise it as something bad
# happened
if isinstance(response, ConnectionError):
raise response
elif isinstance(response, list) and response and \
isinstance(response[0], ConnectionError):
raise response[0]
return response
def connect_to(self, address):
self.host, self.port = address
super(SentinelManagedConnection, self).connect()
if self.connection_pool.check_connection:
self.send_command('PING')
if nativestr(self.read_response()) != 'PONG':
raise ConnectionError('PING failed')
def get_connection(self, command_name, *keys, **options):
"""
Get a connection, blocking for ``self.timeout`` until a connection
is available from the pool.
If the connection returned is ``None`` then creates a new connection.
Because we use a last-in first-out queue, the existing connections
(having been returned to the pool after the initial ``None`` values
were added) will be returned before ``None`` values. This means we only
create new connections when we need to, i.e.: the actual number of
connections will only increase in response to demand.
"""
# Make sure we haven't changed process.
self._checkpid()
# Try and get a connection from the pool. If one isn't available within
# self.timeout then raise a ``ConnectionError``.
connection = None
try:
connection = self.pool.get(block=True, timeout=self.timeout)
except Empty:
# Note that this is not caught by the redis client and will be
# raised unless handled by application code. If you want never to
raise ConnectionError("No connection available.")
# If the ``connection`` is actually ``None`` then that's a cue to make
# a new connection to add to the pool.
if connection is None:
connection = self.make_connection()
return connection
def can_read(self):
if not self._reader:
raise ConnectionError(SERVER_CLOSED_CONNECTION_ERROR)
if self._next_response is False:
self._next_response = self._reader.gets()
return self._next_response is not False
def _read_from_socket(self, length=None):
socket_read_size = self.socket_read_size
buf = self._buffer
buf.seek(self.bytes_written)
marker = 0
try:
while True:
data = self._sock.recv(socket_read_size)
# an empty string indicates the server shutdown the socket
if isinstance(data, bytes) and len(data) == 0:
raise socket.error(SERVER_CLOSED_CONNECTION_ERROR)
buf.write(data)
data_length = len(data)
self.bytes_written += data_length
marker += data_length
if length is not None and length > marker:
continue
break
except socket.timeout:
raise TimeoutError("Timeout reading from socket")
except socket.error:
e = sys.exc_info()[1]
raise ConnectionError("Error while reading from socket: %s" %
(e.args,))
def read_response(self):
try:
return super(SentinelManagedConnection, self).read_response()
except ReadOnlyError:
if self.connection_pool.is_master:
# When talking to a master, a ReadOnlyError when likely
# indicates that the previous master that we're still connected
# to has been demoted to a slave and there's a new master.
# calling disconnect will force the connection to re-query
# sentinel during the next connect() attempt.
self.disconnect()
raise ConnectionError('The previous master is now a slave')
raise
def on_connect(self):
"Initialize the connection, authenticate and select a database"
self._parser.on_connect(self)
# if a password is specified, authenticate
if self.password:
self.send_command('AUTH', self.password)
if nativestr(self.read_response()) != 'OK':
raise AuthenticationError('Invalid Password')
# if a database is specified, switch to it
if self.db:
self.send_command('SELECT', self.db)
if nativestr(self.read_response()) != 'OK':
raise ConnectionError('Invalid Database')
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
def connect(self):
"Connects to the Redis server if not already connected"
if self._sock:
return
try:
sock = self._connect()
except socket.error:
e = sys.exc_info()[1]
raise ConnectionError(self._error_message(e))
self._sock = sock
try:
self.on_connect()
except RedisError:
# clean up after any error in on_connect
self.disconnect()
raise
# run any user callbacks. right now the only internal callback
# is for pubsub channel/pattern resubscription
for callback in self._connect_callbacks:
callback(self)
def send_packed_command(self, command):
"Send an already packed command to the Redis server"
if not self._sock:
self.connect()
try:
if isinstance(command, str):
command = [command]
for item in command:
self._sock.sendall(item)
except socket.timeout:
self.disconnect()
raise TimeoutError("Timeout writing to socket")
except socket.error:
e = sys.exc_info()[1]
self.disconnect()
if len(e.args) == 1:
_errno, errmsg = 'UNKNOWN', e.args[0]
else:
_errno, errmsg = e.args
raise ConnectionError("Error %s while writing to socket. %s." %
(_errno, errmsg))
except:
self.disconnect()
raise
def make_connection(self):
"Create a new connection"
if self._created_connections >= self.max_connections:
raise ConnectionError("Too many connections")
self._created_connections += 1
return self.connection_class(**self.connection_kwargs)