def loop(rc, reset_last_key=None):
"""
Regular debug loop that can be used to test how redis behaves during changes in the cluster.
"""
if reset_last_key:
rc.set("__last__", 0)
last = False
while last is False:
try:
last = rc.get("__last__")
last = 0 if not last else int(last)
print("starting at foo{0}".format(last))
except Exception as e:
print("error {0}".format(e))
time.sleep(1)
for i in xrange(last, 1000000000): # noqa
try:
print("SET foo{0} {1}".format(i, i))
rc.set("foo{0}".format(i), i)
got = rc.get("foo{0}".format(i))
print("GET foo{0} {1}".format(i, got))
rc.set("__last__", i)
except Exception as e:
print("error {0}".format(e))
time.sleep(0.05)
def timeit(rc, itterations=50000):
"""
Time how long it take to run a number of set/get:s
"""
t0 = time.time()
for i in xrange(0, itterations): # noqa
s = "foo{0}".format(i)
rc.set(s, i)
rc.get(s)
t1 = time.time() - t0
print("{0}k SET/GET operations took: {1} seconds... {2} operations per second".format((itterations / 1000) * 2, t1, (itterations / t1) * 2))
def read_response(self):
try:
response = self._buffer.readline()
except:
print("SC Debug: race condition that the _buffer is already released")
return None
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):
response = self.encoder.decode(response)
return response
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)
response = convertToNumber(response)
return response
def timeit_pipeline(rc, itterations=50000):
"""
Time how long it takes to run a number of set/get:s inside a cluster pipeline
"""
t0 = time.time()
for i in xrange(0, itterations): # noqa
s = "foo{0}".format(i)
p = rc.pipeline()
p.set(s, i)
p.get(s)
p.execute()
t1 = time.time() - t0
print("{0}k SET/GET operations inside pipelines took: {1} seconds... {2} operations per second".format(
(itterations / 1000) * 2, t1, (itterations / t1) * 2)
)
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 timeit_pipeline(rc, itterations=50000):
"""
Time how long it takes to run a number of set/get:s inside a cluster pipeline
"""
t0 = time.time()
for i in xrange(0, itterations): # noqa
s = "foo{0}".format(i)
p = rc.pipeline()
p.set(s, i)
p.get(s)
p.execute()
t1 = time.time() - t0
print("{0}k SET/GET operations inside pipelines took: {1} seconds... {2} operations per second".format(
(itterations / 1000) * 2, t1, (itterations / t1) * 2)
)
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.read()
if not response:
raise ConnectionError("Socket closed on remote end")
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.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 _execute_pipeline(self, connection, commands, raise_on_error):
"""
Code borrowed from StrictRedis so it can be fixed
"""
# build up all commands into a single request to increase network perf
if self.explicit_transaction:
# build up all commands into a single request to increase network perf
cmds = chain([(('MULTI', ), {})], commands, [(('EXEC', ), {})])
all_cmds = connection.pack_commands([args for args, _ in cmds])
else:
all_cmds = connection.pack_commands([args for args, _ in commands])
try:
connection.send_packed_command(all_cmds)
except ConnectionError as e:
return [e for _ in xrange(len(commands))] # noqa
response = []
if self.explicit_transaction:
# Get rid of multi values (OK, QUEUED...)
self.parse_response(connection, "_")
for _, _ in enumerate(commands):
self.parse_response(connection, "_")
response = self.parse_response(connection, "_")
if response is None:
raise WatchError("Watched variable changed.")
for r, cmd in izip(response, commands):
response.append(r)
self.explicit_transaction = False
self.watching = False
else:
for args, options in commands:
try:
response.append(self.parse_response(connection, args[0], **options))
except (ConnectionError, ResponseError):
response.append(sys.exc_info()[1])
if raise_on_error:
self.raise_first_error(commands, response)
return response
def read_response(self):
response = self.read()
if not response:
raise ConnectionError("Socket closed on remote end")
byte, response = byte_to_chr(response[0]), response[1:]
if byte not in ('-', '+', ':', '$', '*'):
raise InvalidResponse("Protocol Error")
# server returned an error
if byte == '-':
if nativestr(response).startswith('LOADING '):
# if we're loading the dataset into memory, kill the socket
# so we re-initialize (and re-SELECT) next time.
raise ConnectionError("Redis is loading data into memory")
# if the error starts with ERR, trim that off
if nativestr(response).startswith('ERR '):
response = response[4:]
# *return*, not raise the exception class. if it is meant to be
# raised, it will be at a higher level.
return ResponseError(response)
# single value
elif byte == '+':
pass
# int value
elif byte == ':':
response = long(response)
# bulk response
elif byte == '$':
length = int(response)
if length == -1:
return None
response = self.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 read_response(self):
try:
response = yield self._stream.read_until(SYM_CRLF)
except StreamClosedError:
raise socket.error(SERVER_CLOSED_CONNECTION_ERROR)
response = response[:-2]
if not response:
raise ConnectionError(SERVER_CLOSED_CONNECTION_ERROR)
byte, response = byte_to_chr(response[0]), response[1:]
if byte not in ('-', '+', ':', '$', '*'):
raise InvalidResponse("Protocol Error: %s, %s" %
(str(byte), str(response)))
if byte == '-':
response = nativestr(response)
error = self.parse_error(response)
if isinstance(error, ConnectionError):
raise error
raise gen.Return(error)
elif byte == '+':
pass
elif byte == ':':
response = long(response)
elif byte == '$':
length = int(response)
if length == -1:
raise gen.Return(None)
response = yield self._stream.read_bytes(
length + 2) # make sure to read the '\r\n'
response = response[:-2]
elif byte == '*':
length = int(response)
if length == -1:
raise gen.Return(None)
response = []
for i in xrange(length):
part = yield self.read_response()
response.append(part)
if isinstance(response, bytes):
response = self.encoder.decode(response)
raise gen.Return(response)
def read_response(self):
response = self.read()
if not response:
raise ConnectionError("Socket closed on remote end")
byte, response = byte_to_chr(response[0]), response[1:]
if byte not in ("-", "+", ":", "$", "*"):
raise InvalidResponse("Protocol Error")
# server returned an error
if byte == "-":
response = nativestr(response)
if response.startswith("LOADING "):
# if we're loading the dataset into memory, kill the socket
# so we re-initialize (and re-SELECT) next time.
raise ConnectionError("Redis is loading data into memory")
# *return*, not raise the exception class. if it is meant to be
# raised, it will be at a higher level.
return self.parse_error(response)
# single value
elif byte == "+":
pass
# int value
elif byte == ":":
response = long(response)
# bulk response
elif byte == "$":
length = int(response)
if length == -1:
return None
response = self.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 _execute_pipeline(self, connection, commands, raise_on_error):
"""
Code borrowed from StrictRedis so it can be fixed
"""
# build up all commands into a single request to increase network perf
all_cmds = connection.pack_commands([args for args, _ in commands])
try:
connection.send_packed_command(all_cmds)
except ConnectionError as e:
return [e for _ in xrange(len(commands))] # noqa
response = []
for args, options in commands:
try:
response.append(self.parse_response(connection, args[0], **options))
except (ConnectionError, ResponseError):
response.append(sys.exc_info()[1])
if raise_on_error:
self.raise_first_error(commands, response)
return response
def _execute_pipeline(self, connection, commands, raise_on_error):
"""
Code borrowed from StrictRedis so it can be fixed
"""
# build up all commands into a single request to increase network perf
all_cmds = connection.pack_commands([args for args, _ in commands])
try:
connection.send_packed_command(all_cmds)
except ConnectionError as e:
return [e for _ in xrange(len(commands))] # noqa
response = []
for args, options in commands:
try:
response.append(
self.parse_response(connection, args[0], **options))
except (ConnectionError, ResponseError):
response.append(sys.exc_info()[1])
if raise_on_error:
self.raise_first_error(commands, response)
return response
def read_response(self):
response = self.read()
if not response:
raise ConnectionError("Socket closed on remote end")
byte, response = byte_to_chr(response[0]), response[1:]
if byte not in ('-', '+', ':', '$', '*'):
raise InvalidResponse("Protocol Error")
# server returned an error
if byte == '-':
response = nativestr(response)
# *return*, not raise the exception class. if it is meant to be
# raised, it will be at a higher level.
return self.parse_error(response)
# single value
elif byte == '+':
pass
# int value
elif byte == ':':
response = long(response)
# bulk response
elif byte == '$':
length = int(response)
if length == -1:
return None
response = self.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
from redis._compat import xrange
from others.redis.cluster import rc
from others.redis.cluster import current_milli_time
s = current_milli_time()
for i in xrange(1000000):
d = str(i)
rc.set(d, d)
rc.incrby(d, 1)
print current_milli_time() - s
# 1824127
# 1482678 32 conn
def publisher(n):
time.sleep(1)
for i in xrange(n):
conn.publish('channel', i)
time.sleep(1)
from redis._compat import xrange
from others.redis.cluster import rc
from others.redis.cluster import current_milli_time
s = current_milli_time()
for i in xrange(1000000):
d = str(i)
rc.set(d, d)
rc.incrby(d, 1)
print current_milli_time() - s
# 1824127
# 1482678 32 conn
def get_online_users():
current = int(time.time()) // 60
minutes = xrange(app.config['ONLINE_LAST_MINUTES'])
return redis.sunion(['online-users/%d' % (current - x) for x in minutes])
def read_response(self):
'''
Reads one line from the wire, and interprets it.
Example: the acknowledgment to an unsubscribe
from topic myTopic on the wire looks like this:
*3\r\n$11\r\nUNSUBSCRIBE\r\n$7\r\nmyTopic\r\n:1\r\n'
*3 # three items to follow
$11 # string of 11 chars
UNSUBSCRIBE
$7 # string of 7 chars
myTopic
:1 # one topic subscribed to now
Each line will cause a recursive call to this method
(see elif byte == '*' below).
Simpler calls will be individual elements, such
as ':12', which returns the integer 12.
These are the possible prefixes; each item
is followed by a \r\n, which is stripped
by SocketLineReader:
+<str> simple string
:<int> integer
$<n> string of length <n>
*<num> start of array with <num> elements
When the message to parse is the acknowledgment of
a SUBSCRIBE or UNSUBSCRIBE command, this method
will set() event self.unsubscribeAckEvent/self.unsubscribeAckEvent.
:return: response string
:rtype: string
'''
response = self._buffer.readline()
if not response:
raise ConnectionError(SERVER_CLOSED_CONNECTION_ERROR)
byte, response = byte_to_chr(response[0]), response[1:]
if byte not in ('-', '+', ':', '$', '*'):
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
# simple-string: response holds result:
elif byte == '+':
pass
# int value
elif byte == ':':
response = long(response)
# bulk response
elif byte == '$':
length = int(response)
if length == -1:
# Null string:
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 _ in xrange(length)]
if isinstance(response, bytes) and self.encoding:
response = response.decode(self.encoding)
#***********
#print('Response: %s' % byte + '|' + str(response))
#***********
return response
def send_cluster_commands(self, stack, raise_on_error=True, allow_redirections=True):
"""
Send a bunch of cluster commands to the redis cluster.
`allow_redirections` If the pipeline should follow `ASK` & `MOVED` responses
automatically. If set to false it will raise RedisClusterException.
"""
if self.refresh_table_asap:
self.connection_pool.nodes.initialize()
self.refresh_table_asap = False
ttl = self.RedisClusterRequestTTL
# this is where we store all the responses to the pipeline execute.
# the actual response is a list, not a dict, but because we may be getting
# the responses for commands out of order or sometimes retrying them it is important
# that we have a way to key the responses by the order they came in so that we can return
# the responses as if we did them sequentially.
response = {}
# `attempt` corresponds to the sequence number of commands still left to process or retry.
# initially this corresponds exactly to the number of commands we need to run, and if all goes
# well, that's where it'll end. Everything will be attempted once, and we end up with an empty
# array of commands left to process. But if we need to retry, `attempt` gets repopulated with
# the sequence number of the command that is being retried.
attempt = xrange(0, len(stack)) if stack else [] # noqa
# there are different types of retries. redis cluster says if it responds with an ASK error,
# you need to handle it differently than a moved error. And if we hit a connection error, we
# don't really know what to do for that command so we pick a random other node in the cluster.
ask_retry = {}
conn_retry = {}
# as long as we have commands left to attempt and we haven't overrun the max attempts, keep trying.
while attempt and ttl > 0:
# decrement our counter for number of attempts left before giving up.
ttl -= 1
# each time we go through this we need to separate out the commands by node.
node_commands = {}
# build a list of node objects based on node names we need to
nodes = {}
# as we move through each command that still needs to be processed,
# we figure out the slot number that command maps to, then from the slot determine the node.
slots = set()
for i in attempt:
c = stack[i]
slot = self._determine_slot(*c[0])
slots.add(slot)
if self.explicit_transaction and len(slots) > 1:
raise WatchError("Cannot run explicit transaction against more than 1 hashslot, keys: {}."
.format([str(c[0][1]) for c in stack]))
# normally we just refer to our internal node -> slot table that tells us where a given
# command should route to.
# but if we are retrying, the cluster could have told us we were wrong or the node was down.
# in that case, we have to try something that contradicts our rules.
if i in ask_retry:
node = ask_retry[i]
elif i in conn_retry:
node = conn_retry[i]
else:
if self.refresh_table_asap: # MOVED
node = self.connection_pool.get_master_node_by_slot(slot)
else:
node = self.connection_pool.get_node_by_slot(slot)
# little hack to make sure the node name is populated. probably could clean this up.
self.connection_pool.nodes.set_node_name(node)
# now that we know the name of the node ( it's just a string in the form of host:port )
# we can build a list of commands for each node.
node_name = node['name']
nodes[node_name] = node
node_commands.setdefault(node_name, {})
node_commands[node_name][i] = c
# Get one connection at a time from the pool and basiccly copy the logic from
# _execute_pipeline() below and do what a normal pipeline does.
# now that we've split out the commands by the node we plan to send them to,
# we can reset the commands we'll attempt next time around back to nothing.
# when we process the response, any commands that need to be retried because of
# connection errors, MOVED errors, or ASKING errors will be dumped into here.
# most of the time this array will just stay empty.
attempt = []
# only use threads when it makes sense performance-wise to do so.
# if you are doing an ask_retry, explicitly disable it.
# makes it easier to define the logic of how to do the ASKING command,
# and in practice, the server will only be moving one slot at a time,
# so there will only be one server that will be recieving these ASKING retries
# anyway.
if self.use_threads and not ask_retry and len(node_commands) > 1:
# for each node we query, we need to have one worker.
# that way all pipelined commands are issued in parallel.
# this could be a problem if you have hundreds of nodes in your cluster.
# We should really refactor this to be a thread pool of workers, and allocate up to a
# certain max number of threads.
workers = dict()
# allocate all of the redis connections from the connection pool.
# each connection gets passed into its own thread so it can query each node in paralle.
connections = {
node_name: self.connection_pool.get_connection_by_node(nodes[node_name])
for node_name in node_commands
}
# iterate through each set of commands and pass them into a worker thread so
# it can be executed in it's own socket connection from the redis connection pool
# in parallel.
try:
for node_name in node_commands:
node = nodes[node_name]
# build the list of commands to be passed to a particular node.
# we have to do this on each attempt, because the cluster may respond to us
# that a command for a given slot actually should be routed to a different node.
cmds = [node_commands[node_name][i] for i in sorted(node_commands[node_name].keys())]
# pass all the commands bound for a particular node into a thread worker object
# along with the redis connection needed to run the commands and parse the response.
workers[node_name] = ThreadedPipelineExecute(
execute=self._execute_pipeline,
conn=connections[node_name],
cmds=cmds)
workers[node_name].start()
# now that all the queries are running against all the nodes,
# wait for all of them to come back so we can parse the responses.
for node_name, worker in workers.items():
worker.join()
# if the worker hit an exception this is really bad.
# that means something completely unexpected happened.
# we have to assume the worst and assume that all the calls against
# that particular node in the cluster failed and will need to be retried.
# maybe that isn't a safe assumption?
if worker.exception:
for i in node_commands[node_name].keys():
response[i] = worker.exception
else:
# we got a valid response back from redis.
# map each response based on the sequence of the original request stack.
# some of these responses may represent redis connection or ask errors etc.
for i, v in zip(sorted(node_commands[node_name].keys()), worker.value):
response[i] = v
finally:
# don't need our threads anymore.
# explicitly remove them from the current namespace so they can be garbage collected.
del workers
# release all of the redis connections we allocated earlier back into the connection pool.
for conn in connections.values():
self.connection_pool.release(conn)
del connections
else:
# if we got here, it's because threading is disabled explicitly, or
# all the commands map to a single node so we don't need to use different threads to
# issue commands in parallel.
# first, we need to keep track of all the commands and what responses they map to.
# this is because we need to interject ASKING commands into the mix. I thought of a little
# hack to map these responses back to None instead of the integer sequence id that was the
# position number of the command issued in the stack of command requests at the point pipeline
# execute was issued.
track_cmds = {}
# send the commands in sequence.
for node_name in node_commands:
node = nodes[node_name]
cmds = []
track_cmds[node_name] = []
# we've got the commands we need to run for each node,
# sort them to make sure that they are executed in the same order
# they came in on the stack otherwise it changes the logic.
# we make no guarantees about the order of execution of the commands run
# except that we are sure we will always process the commands for a given key
# in a sequential order. If we get an error from the server about a given key,
# that will apply the same for all commands on that key (MOVED, ASKING, etc)
# so we will be resending all of the commands for that key to a new node.
for i in sorted(node_commands[node_name].keys()):
if i in ask_retry:
# put in our fake stub placeholder for the response.
track_cmds[node_name].append(None)
cmds.append((['ASKING'], {}))
# keep track of the sequence number and the mapping of actual commands
# sent to the node. (ASKING SCREWS EVERYTHING UP!!!!!)
track_cmds[node_name].append(i)
cmds.append(node_commands[node_name][i])
# allocate a connection from the connection pool and send the commands for each node
# as a packed single network request. Since we aren't using threads here, we are
# only able to send each request sequentially and block, waiting for the response.
# After we get the response to one connection, we move on to the next.
with by_node_context(self.connection_pool, node) as connection:
result = zip(
track_cmds[node_name],
self._execute_pipeline(connection, cmds, False))
# map the response from the connection to the commands we were running.
for i, v in result:
# remember None is a shim value used above as a placeholder for the ASKING
# command. That response is just `OK` and we don't care about that.
# throw it away.
# Map the response here to the original sequence of commands in the stack
# sent to pipeline.
if i is not None:
response[i] = v
ask_retry = {}
conn_retry = {}
# now that we have tried to execute all the commands let's see what we have left.
for i, v in response.items():
# if the response isn't an exception it is a valid response from the node
# we're all done with that command, YAY!
# if we move beyond this point, we've run into problems and we need to retry the command.
if not isinstance(v, Exception):
continue
# connection errors are tricky because most likely we routed to the right node but it is
# down. In that case, the best we can do is randomly try another node in the cluster
# and hope that it tells us to try that node again with a MOVED error or tells us the new
# master.
if isinstance(v, ConnectionError):
conn_retry[i] = random.choice(self.startup_nodes)
attempt.append(i)
# if we are stuck in a retry loop, slow things down a bit to give the failover
# a chance of actually happening.
if ttl < self.RedisClusterRequestTTL / 2:
time.sleep(0.1)
continue
# If cluster is down it should be raised and bubble up to
# utils.clusterdown_wrapper()
if isinstance(v, ClusterDownError):
self.connection_pool.disconnect()
self.connection_pool.reset()
self.refresh_table_asap = True
raise v
# A MOVED response from the cluster means that somehow we were misinformed about which node
# a given key slot maps to. This can happen during cluster resharding, during master-slave
# failover, or if we got a connection error and were forced to re-attempt the command against a
# random node.
if isinstance(v, MovedError):
# Do not perform full cluster refresh on every MOVED error
self.reinitialize_counter += 1
if self.reinitialize_counter % self.reinitialize_steps == 0:
self.refresh_table_asap = True
node = self.connection_pool.nodes.set_node(v.host, v.port, server_type='master')
self.connection_pool.nodes.slots[v.slot_id][0] = node
attempt.append(i)
self._fail_on_redirect(allow_redirections)
# an ASK error from the server means that only this specific command needs to be tried against
# a different server (not every key in the slot). This happens only during cluster re-sharding
# and is a major pain in the ass. For it to work correctly, we have to resend the command to
# the new node but only after first sending an ASKING command immediately beforehand.
elif isinstance(v, AskError):
node = self.connection_pool.nodes.set_node(v.host, v.port, server_type='master')
ask_retry[i] = node
attempt.append(i)
self._fail_on_redirect(allow_redirections)
# YAY! we made it out of the attempt loop.
# turn the response back into a simple flat array that corresponds
# to the sequence of commands issued in the stack in pipeline.execute()
response = [response[k] for k in sorted(response.keys())]
if raise_on_error:
self.raise_first_error(stack, response)
return response
def read_response(self):
'''
Reads one line from the wire, and interprets it.
Example: the acknowledgment to an unsubscribe
from topic myTopic on the wire looks like this:
*3\r\n$11\r\nUNSUBSCRIBE\r\n$7\r\nmyTopic\r\n:1\r\n'
*3 # three items to follow
$11 # string of 11 chars
UNSUBSCRIBE
$7 # string of 7 chars
myTopic
:1 # one topic subscribed to now
Each line will cause a recursive call to this method
(see elif byte == '*' below).
Simpler calls will be individual elements, such
as ':12', which returns the integer 12.
These are the possible prefixes; each item
is followed by a \r\n, which is stripped
by SocketLineReader:
+<str> simple string
:<int> integer
$<n> string of length <n>
*<num> start of array with <num> elements
When the message to parse is the acknowledgment of
a SUBSCRIBE or UNSUBSCRIBE command, this method
will set() event self.unsubscribeAckEvent/self.unsubscribeAckEvent.
:return: response string
:rtype: string
'''
response = self._buffer.readline()
if not response:
raise ConnectionError(SERVER_CLOSED_CONNECTION_ERROR)
byte, response = byte_to_chr(response[0]), response[1:]
if byte not in ('-', '+', ':', '$', '*'):
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
# simple-string: response holds result:
elif byte == '+':
pass
# int value
elif byte == ':':
response = long(response)
# bulk response
elif byte == '$':
length = int(response)
if length == -1:
# Null string:
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 _ in xrange(length)]
if isinstance(response, bytes) and self.encoding:
response = response.decode(self.encoding)
#***********
#print('Response: %s' % byte + '|' + str(response))
#***********
return response
def send_cluster_commands(self,
stack,
raise_on_error=True,
allow_redirections=True):
"""
Send a bunch of cluster commands to the redis cluster.
`allow_redirections` If the pipeline should follow `ASK` & `MOVED` responses
automatically. If set to false it will raise RedisClusterException.
"""
if self.refresh_table_asap:
self.connection_pool.nodes.initialize()
self.refresh_table_asap = False
ttl = self.RedisClusterRequestTTL
response = {}
attempt = xrange(0, len(stack)) if stack else [] # noqa
ask_slots = {}
while attempt and ttl > 0:
ttl -= 1
node_commands = {}
nodes = {}
# Keep this section so that we can determine what nodes to contact
for i in attempt:
c = stack[i]
slot = self._determine_slot(*c[0], **c[1])
if slot in ask_slots:
node = ask_slots[slot]
else:
node = self.connection_pool.nodes.slots[slot]
self.connection_pool.nodes.set_node_name(node)
node_name = node['name']
nodes[node_name] = node
node_commands.setdefault(node_name, {})
node_commands[node_name][i] = c
# Get one connection at a time from the pool and basiccly copy the logic from
# _execute_pipeline() below and do what a normal pipeline does.
attempt = []
if self.use_threads and len(node_commands) > 1:
workers = dict()
for node_name in node_commands:
node = nodes[node_name]
cmds = [
node_commands[node_name][i]
for i in sorted(node_commands[node_name].keys())
]
with by_node_context(self.connection_pool,
node) as connection:
workers[node_name] = Worker(self._execute_pipeline,
connection, cmds, False)
workers[node_name].start()
for node_name, worker in workers.items():
worker.join()
if worker.exception:
for i in sorted(node_commands[node_name].keys()):
response[i] = worker.exception
else:
for i, v in zip(
sorted(node_commands[node_name].keys()),
worker.value):
response[i] = v
del workers
else:
for node_name in node_commands:
node = nodes[node_name]
cmds = [
node_commands[node_name][i]
for i in sorted(node_commands[node_name].keys())
]
with by_node_context(self.connection_pool,
node) as connection:
result = zip(
sorted(node_commands[node_name].keys()),
self._execute_pipeline(connection, cmds, False))
for i, v in result:
response[i] = v
ask_slots = {}
for i, v in response.items():
if not isinstance(v, Exception):
continue
if isinstance(v, ConnectionError):
ask_slots[self.connection_pool.nodes.keyslot(
stack[i][0][1])] = random.choice(self.startup_nodes)
attempt.append(i)
if ttl < self.RedisClusterRequestTTL / 2:
time.sleep(0.1)
continue
errv = RedisCluster._exception_message(v)
if errv is None:
continue
if errv.startswith('CLUSTERDOWN'):
self.connection_pool.disconnect()
self.connection_pool.reset()
self.refresh_table_asap = True
raise ClusterDownException()
redir = self.parse_redirection_exception_msg(errv)
if not redir:
continue
if redir['action'] == "MOVED":
self.refresh_table_asap = True
node = self.connection_pool.nodes.set_node(
redir['host'], redir['port'], server_type='master')
self.connection_pool.nodes.slots[redir['slot']] = node
attempt.append(i)
self._fail_on_redirect(allow_redirections)
elif redir['action'] == "ASK":
node = self.connection_pool.nodes.set_node(
redir['host'], redir['port'], server_type='master')
ask_slots[redir['slot']] = node
attempt.append(i)
self._fail_on_redirect(allow_redirections)
response = [response[k] for k in sorted(response.keys())]
if raise_on_error:
self.raise_first_error(stack, response)
return response
def low_zeros(value):
for i in xrange(1, 32):
if value >> i << i != value:
break
return i - 1
def send_cluster_commands(self, stack, raise_on_error=True, allow_redirections=True):
"""
Send a bunch of cluster commands to the redis cluster.
`allow_redirections` If the pipeline should follow `ASK` & `MOVED` responses
automatically. If set to false it will raise RedisClusterException.
"""
if self.refresh_table_asap:
self.connection_pool.nodes.initialize()
self.refresh_table_asap = False
ttl = self.RedisClusterRequestTTL
response = {}
attempt = xrange(0, len(stack)) if stack else [] # noqa
ask_slots = {}
while attempt and ttl > 0:
ttl -= 1
node_commands = {}
nodes = {}
# Keep this section so that we can determine what nodes to contact
for i in attempt:
c = stack[i]
slot = self._determine_slot(*c[0])
if slot in ask_slots:
node = ask_slots[slot]
else:
node = self.connection_pool.nodes.slots[slot]
self.connection_pool.nodes.set_node_name(node)
node_name = node['name']
nodes[node_name] = node
node_commands.setdefault(node_name, {})
node_commands[node_name][i] = c
# Get one connection at a time from the pool and basiccly copy the logic from
# _execute_pipeline() below and do what a normal pipeline does.
attempt = []
if self.use_threads and len(node_commands) > 1:
workers = dict()
for node_name in node_commands:
node = nodes[node_name]
cmds = [node_commands[node_name][i] for i in sorted(node_commands[node_name].keys())]
with by_node_context(self.connection_pool, node) as connection:
workers[node_name] = Worker(self._execute_pipeline, connection, cmds, False)
workers[node_name].start()
for node_name, worker in workers.items():
worker.join()
if worker.exception:
for i in sorted(node_commands[node_name].keys()):
response[i] = worker.exception
else:
for i, v in zip(sorted(node_commands[node_name].keys()), worker.value):
response[i] = v
del workers
else:
for node_name in node_commands:
node = nodes[node_name]
cmds = [node_commands[node_name][i] for i in sorted(node_commands[node_name].keys())]
with by_node_context(self.connection_pool, node) as connection:
result = zip(
sorted(node_commands[node_name].keys()),
self._execute_pipeline(connection, cmds, False))
for i, v in result:
response[i] = v
ask_slots = {}
for i, v in response.items():
if not isinstance(v, Exception):
continue
if isinstance(v, ConnectionError):
ask_slots[self.connection_pool.nodes.keyslot(stack[i][0][1])] = random.choice(self.startup_nodes)
attempt.append(i)
if ttl < self.RedisClusterRequestTTL / 2:
time.sleep(0.1)
continue
errv = StrictRedisCluster._exception_message(v)
if errv is None:
continue
if errv.startswith('CLUSTERDOWN'):
self.connection_pool.disconnect()
self.connection_pool.reset()
self.refresh_table_asap = True
raise ClusterDownException()
redir = self.parse_redirection_exception_msg(errv)
if not redir:
continue
if redir['action'] == "MOVED":
self.refresh_table_asap = True
node = self.connection_pool.nodes.set_node(redir['host'], redir['port'], server_type='master')
self.connection_pool.nodes.slots[redir['slot']] = node
attempt.append(i)
self._fail_on_redirect(allow_redirections)
elif redir['action'] == "ASK":
node = self.connection_pool.nodes.set_node(redir['host'], redir['port'], server_type='master')
ask_slots[redir['slot']] = node
attempt.append(i)
self._fail_on_redirect(allow_redirections)
response = [response[k] for k in sorted(response.keys())]
if raise_on_error:
self.raise_first_error(stack, response)
return response
def send_cluster_commands(self,
stack,
raise_on_error=True,
allow_redirections=True):
"""
Send a bunch of cluster commands to the redis cluster.
`allow_redirections` If the pipeline should follow `ASK` & `MOVED` responses
automatically. If set to false it will raise RedisClusterException.
"""
if self.refresh_table_asap:
self.connection_pool.nodes.initialize()
self.refresh_table_asap = False
ttl = self.RedisClusterRequestTTL
# this is where we store all the responses to the pipeline execute.
# the actual response is a list, not a dict, but because we may be getting
# the responses for commands out of order or sometimes retrying them it is important
# that we have a way to key the responses by the order they came in so that we can return
# the responses as if we did them sequentially.
response = {}
# `attempt` corresponds to the sequence number of commands still left to process or retry.
# initially this corresponds exactly to the number of commands we need to run, and if all goes
# well, that's where it'll end. Everything will be attempted once, and we end up with an empty
# array of commands left to process. But if we need to retry, `attempt` gets repopulated with
# the sequence number of the command that is being retried.
attempt = xrange(0, len(stack)) if stack else [] # noqa
# there are different types of retries. redis cluster says if it responds with an ASK error,
# you need to handle it differently than a moved error. And if we hit a connection error, we
# don't really know what to do for that command so we pick a random other node in the cluster.
ask_retry = {}
conn_retry = {}
# as long as we have commands left to attempt and we haven't overrun the max attempts, keep trying.
while attempt and ttl > 0:
# decrement our counter for number of attempts left before giving up.
ttl -= 1
# each time we go through this we need to separate out the commands by node.
node_commands = {}
# build a list of node objects based on node names we need to
nodes = {}
# as we move through each command that still needs to be processed,
# we figure out the slot number that command maps to, then from the slot determine the node.
for i in attempt:
c = stack[i]
slot = self._determine_slot(*c[0])
# normally we just refer to our internal node -> slot table that tells us where a given
# command should route to.
# but if we are retrying, the cluster could have told us we were wrong or the node was down.
# in that case, we have to try something that contradicts our rules.
if i in ask_retry:
node = ask_retry[i]
elif i in conn_retry:
node = conn_retry[i]
else:
if self.refresh_table_asap: # MOVED
node = self.connection_pool.get_master_node_by_slot(
slot)
else:
node = self.connection_pool.get_node_by_slot(slot)
# little hack to make sure the node name is populated. probably could clean this up.
self.connection_pool.nodes.set_node_name(node)
# now that we know the name of the node ( it's just a string in the form of host:port )
# we can build a list of commands for each node.
node_name = node['name']
nodes[node_name] = node
node_commands.setdefault(node_name, {})
node_commands[node_name][i] = c
# Get one connection at a time from the pool and basiccly copy the logic from
# _execute_pipeline() below and do what a normal pipeline does.
# now that we've split out the commands by the node we plan to send them to,
# we can reset the commands we'll attempt next time around back to nothing.
# when we process the response, any commands that need to be retried because of
# connection errors, MOVED errors, or ASKING errors will be dumped into here.
# most of the time this array will just stay empty.
attempt = []
# only use threads when it makes sense performance-wise to do so.
# if you are doing an ask_retry, explicitly disable it.
# makes it easier to define the logic of how to do the ASKING command,
# and in practice, the server will only be moving one slot at a time,
# so there will only be one server that will be recieving these ASKING retries
# anyway.
if self.use_threads and not ask_retry and len(node_commands) > 1:
# for each node we query, we need to have one worker.
# that way all pipelined commands are issued in parallel.
# this could be a problem if you have hundreds of nodes in your cluster.
# We should really refactor this to be a thread pool of workers, and allocate up to a
# certain max number of threads.
workers = dict()
# allocate all of the redis connections from the connection pool.
# each connection gets passed into its own thread so it can query each node in paralle.
connections = {
node_name: self.connection_pool.get_connection_by_node(
nodes[node_name])
for node_name in node_commands
}
# iterate through each set of commands and pass them into a worker thread so
# it can be executed in it's own socket connection from the redis connection pool
# in parallel.
try:
for node_name in node_commands:
node = nodes[node_name]
# build the list of commands to be passed to a particular node.
# we have to do this on each attempt, because the cluster may respond to us
# that a command for a given slot actually should be routed to a different node.
cmds = [
node_commands[node_name][i]
for i in sorted(node_commands[node_name].keys())
]
# pass all the commands bound for a particular node into a thread worker object
# along with the redis connection needed to run the commands and parse the response.
workers[node_name] = ThreadedPipelineExecute(
execute=self._execute_pipeline,
conn=connections[node_name],
cmds=cmds)
workers[node_name].start()
# now that all the queries are running against all the nodes,
# wait for all of them to come back so we can parse the responses.
for node_name, worker in workers.items():
worker.join()
# if the worker hit an exception this is really bad.
# that means something completely unexpected happened.
# we have to assume the worst and assume that all the calls against
# that particular node in the cluster failed and will need to be retried.
# maybe that isn't a safe assumption?
if worker.exception:
for i in node_commands[node_name].keys():
response[i] = worker.exception
else:
# we got a valid response back from redis.
# map each response based on the sequence of the original request stack.
# some of these responses may represent redis connection or ask errors etc.
for i, v in zip(
sorted(node_commands[node_name].keys()),
worker.value):
response[i] = v
finally:
# don't need our threads anymore.
# explicitly remove them from the current namespace so they can be garbage collected.
del workers
# release all of the redis connections we allocated earlier back into the connection pool.
for conn in connections.values():
self.connection_pool.release(conn)
del connections
else:
# if we got here, it's because threading is disabled explicitly, or
# all the commands map to a single node so we don't need to use different threads to
# issue commands in parallel.
# first, we need to keep track of all the commands and what responses they map to.
# this is because we need to interject ASKING commands into the mix. I thought of a little
# hack to map these responses back to None instead of the integer sequence id that was the
# position number of the command issued in the stack of command requests at the point pipeline
# execute was issued.
track_cmds = {}
# send the commands in sequence.
for node_name in node_commands:
node = nodes[node_name]
cmds = []
track_cmds[node_name] = []
# we've got the commands we need to run for each node,
# sort them to make sure that they are executed in the same order
# they came in on the stack otherwise it changes the logic.
# we make no guarantees about the order of execution of the commands run
# except that we are sure we will always process the commands for a given key
# in a sequential order. If we get an error from the server about a given key,
# that will apply the same for all commands on that key (MOVED, ASKING, etc)
# so we will be resending all of the commands for that key to a new node.
for i in sorted(node_commands[node_name].keys()):
if i in ask_retry:
# put in our fake stub placeholder for the response.
track_cmds[node_name].append(None)
cmds.append((['ASKING'], {}))
# keep track of the sequence number and the mapping of actual commands
# sent to the node. (ASKING SCREWS EVERYTHING UP!!!!!)
track_cmds[node_name].append(i)
cmds.append(node_commands[node_name][i])
# allocate a connection from the connection pool and send the commands for each node
# as a packed single network request. Since we aren't using threads here, we are
# only able to send each request sequentially and block, waiting for the response.
# After we get the response to one connection, we move on to the next.
with by_node_context(self.connection_pool,
node) as connection:
result = zip(
track_cmds[node_name],
self._execute_pipeline(connection, cmds, False))
# map the response from the connection to the commands we were running.
for i, v in result:
# remember None is a shim value used above as a placeholder for the ASKING
# command. That response is just `OK` and we don't care about that.
# throw it away.
# Map the response here to the original sequence of commands in the stack
# sent to pipeline.
if i is not None:
response[i] = v
ask_retry = {}
conn_retry = {}
# now that we have tried to execute all the commands let's see what we have left.
for i, v in response.items():
# if the response isn't an exception it is a valid response from the node
# we're all done with that command, YAY!
# if we move beyond this point, we've run into problems and we need to retry the command.
if not isinstance(v, Exception):
continue
# connection errors are tricky because most likely we routed to the right node but it is
# down. In that case, the best we can do is randomly try another node in the cluster
# and hope that it tells us to try that node again with a MOVED error or tells us the new
# master.
if isinstance(v, ConnectionError):
conn_retry[i] = random.choice(self.startup_nodes)
attempt.append(i)
# if we are stuck in a retry loop, slow things down a bit to give the failover
# a chance of actually happening.
if ttl < self.RedisClusterRequestTTL / 2:
time.sleep(0.1)
continue
# If cluster is down it should be raised and bubble up to
# utils.clusterdown_wrapper()
if isinstance(v, ClusterDownError):
self.connection_pool.disconnect()
self.connection_pool.reset()
self.refresh_table_asap = True
raise v
# A MOVED response from the cluster means that somehow we were misinformed about which node
# a given key slot maps to. This can happen during cluster resharding, during master-slave
# failover, or if we got a connection error and were forced to re-attempt the command against a
# random node.
if isinstance(v, MovedError):
# Do not perform full cluster refresh on every MOVED error
self.reinitialize_counter += 1
if self.reinitialize_counter % self.reinitialize_steps == 0:
self.refresh_table_asap = True
node = self.connection_pool.nodes.set_node(
v.host, v.port, server_type='master')
self.connection_pool.nodes.slots[v.slot_id][0] = node
attempt.append(i)
self._fail_on_redirect(allow_redirections)
# an ASK error from the server means that only this specific command needs to be tried against
# a different server (not every key in the slot). This happens only during cluster re-sharding
# and is a major pain in the ass. For it to work correctly, we have to resend the command to
# the new node but only after first sending an ASKING command immediately beforehand.
elif isinstance(v, AskError):
node = self.connection_pool.nodes.set_node(
v.host, v.port, server_type='master')
ask_retry[i] = node
attempt.append(i)
self._fail_on_redirect(allow_redirections)
# YAY! we made it out of the attempt loop.
# turn the response back into a simple flat array that corresponds
# to the sequence of commands issued in the stack in pipeline.execute()
response = [response[k] for k in sorted(response.keys())]
if raise_on_error:
self.raise_first_error(stack, response)
return response