File: //lib/python3.9/site-packages/redis/asyncio/cluster.py
import asyncio
import collections
import random
import socket
import warnings
from typing import (
Any,
Deque,
Dict,
Generator,
List,
Mapping,
Optional,
Type,
TypeVar,
Union,
)
from redis.asyncio.client import ResponseCallbackT
from redis.asyncio.connection import Connection, DefaultParser, Encoder, parse_url
from redis.asyncio.parser import CommandsParser
from redis.client import EMPTY_RESPONSE, NEVER_DECODE, AbstractRedis
from redis.cluster import (
PIPELINE_BLOCKED_COMMANDS,
PRIMARY,
READ_COMMANDS,
REPLICA,
SLOT_ID,
AbstractRedisCluster,
LoadBalancer,
block_pipeline_command,
get_node_name,
parse_cluster_slots,
)
from redis.commands import AsyncRedisClusterCommands
from redis.crc import REDIS_CLUSTER_HASH_SLOTS, key_slot
from redis.exceptions import (
AskError,
BusyLoadingError,
ClusterCrossSlotError,
ClusterDownError,
ClusterError,
ConnectionError,
DataError,
MasterDownError,
MovedError,
RedisClusterException,
ResponseError,
SlotNotCoveredError,
TimeoutError,
TryAgainError,
)
from redis.typing import AnyKeyT, EncodableT, KeyT
from redis.utils import dict_merge, safe_str, str_if_bytes
TargetNodesT = TypeVar(
"TargetNodesT", str, "ClusterNode", List["ClusterNode"], Dict[Any, "ClusterNode"]
)
CONNECTION_ALLOWED_KEYS = (
"client_name",
"db",
"decode_responses",
"encoder_class",
"encoding",
"encoding_errors",
"health_check_interval",
"parser_class",
"password",
"redis_connect_func",
"retry",
"retry_on_timeout",
"socket_connect_timeout",
"socket_keepalive",
"socket_keepalive_options",
"socket_read_size",
"socket_timeout",
"socket_type",
"username",
)
def cleanup_kwargs(**kwargs: Any) -> Dict[str, Any]:
"""Remove unsupported or disabled keys from kwargs."""
return {k: v for k, v in kwargs.items() if k in CONNECTION_ALLOWED_KEYS}
class ClusterParser(DefaultParser):
EXCEPTION_CLASSES = dict_merge(
DefaultParser.EXCEPTION_CLASSES,
{
"ASK": AskError,
"TRYAGAIN": TryAgainError,
"MOVED": MovedError,
"CLUSTERDOWN": ClusterDownError,
"CROSSSLOT": ClusterCrossSlotError,
"MASTERDOWN": MasterDownError,
},
)
class RedisCluster(AbstractRedis, AbstractRedisCluster, AsyncRedisClusterCommands):
"""
Create a new RedisCluster client.
Pass one of parameters:
- `url`
- `host` & `port`
- `startup_nodes`
| Use ``await`` :meth:`initialize` to find cluster nodes & create connections.
| Use ``await`` :meth:`close` to disconnect connections & close client.
Many commands support the target_nodes kwarg. It can be one of the
:attr:`NODE_FLAGS`:
- :attr:`PRIMARIES`
- :attr:`REPLICAS`
- :attr:`ALL_NODES`
- :attr:`RANDOM`
- :attr:`DEFAULT_NODE`
Note: This client is not thread/process/fork safe.
:param host:
| Can be used to point to a startup node
:param port:
| Port used if **host** is provided
:param startup_nodes:
| :class:`~.ClusterNode` to used as a startup node
:param cluster_error_retry_attempts:
| Retry command execution attempts when encountering :class:`~.ClusterDownError`
or :class:`~.ConnectionError`
:param require_full_coverage:
| When set to ``False``: the client will not require a full coverage of the
slots. However, if not all slots are covered, and at least one node has
``cluster-require-full-coverage`` set to ``yes``, the server will throw a
:class:`~.ClusterDownError` for some key-based commands.
| When set to ``True``: all slots must be covered to construct the cluster
client. If not all slots are covered, :class:`~.RedisClusterException` will be
thrown.
| See:
https://redis.io/docs/manual/scaling/#redis-cluster-configuration-parameters
:param reinitialize_steps:
| Specifies the number of MOVED errors that need to occur before reinitializing
the whole cluster topology. If a MOVED error occurs and the cluster does not
need to be reinitialized on this current error handling, only the MOVED slot
will be patched with the redirected node.
To reinitialize the cluster on every MOVED error, set reinitialize_steps to 1.
To avoid reinitializing the cluster on moved errors, set reinitialize_steps to
0.
:param read_from_replicas:
| Enable read from replicas in READONLY mode. You can read possibly stale data.
When set to true, read commands will be assigned between the primary and
its replications in a Round-Robin manner.
:param url:
| See :meth:`.from_url`
:param kwargs:
| Extra arguments that will be passed to the
:class:`~redis.asyncio.connection.Connection` instances when created
:raises RedisClusterException:
if any arguments are invalid. Eg:
- db kwarg
- db != 0 in url
- unix socket connection
- none of host & url & startup_nodes were provided
"""
@classmethod
def from_url(cls, url: str, **kwargs: Any) -> "RedisCluster":
"""
Return a Redis client object configured from the given URL.
For example::
redis://[[username]:[password]]@localhost:6379/0
rediss://[[username]:[password]]@localhost:6379/0
unix://[[username]:[password]]@/path/to/socket.sock?db=0
Three URL schemes are supported:
- `redis://` creates a TCP socket connection. See more at:
<https://www.iana.org/assignments/uri-schemes/prov/redis>
- `rediss://` creates a SSL wrapped TCP socket connection. See more at:
<https://www.iana.org/assignments/uri-schemes/prov/rediss>
- ``unix://``: creates a Unix Domain Socket connection.
The username, password, hostname, path and all querystring values
are passed through urllib.parse.unquote in order to replace any
percent-encoded values with their corresponding characters.
There are several ways to specify a database number. The first value
found will be used:
1. A ``db`` querystring option, e.g. redis://localhost?db=0
2. If using the redis:// or rediss:// schemes, the path argument
of the url, e.g. redis://localhost/0
3. A ``db`` keyword argument to this function.
If none of these options are specified, the default db=0 is used.
All querystring options are cast to their appropriate Python types.
Boolean arguments can be specified with string values "True"/"False"
or "Yes"/"No". Values that cannot be properly cast cause a
``ValueError`` to be raised. Once parsed, the querystring arguments and
keyword arguments are passed to :class:`~redis.asyncio.connection.Connection`
when created. In the case of conflicting arguments, querystring
arguments always win.
"""
return cls(url=url, **kwargs)
__slots__ = (
"_initialize",
"_lock",
"cluster_error_retry_attempts",
"command_flags",
"commands_parser",
"connection_kwargs",
"encoder",
"node_flags",
"nodes_manager",
"read_from_replicas",
"reinitialize_counter",
"reinitialize_steps",
"response_callbacks",
"result_callbacks",
)
def __init__(
self,
host: Optional[str] = None,
port: int = 6379,
startup_nodes: Optional[List["ClusterNode"]] = None,
require_full_coverage: bool = False,
read_from_replicas: bool = False,
cluster_error_retry_attempts: int = 3,
reinitialize_steps: int = 10,
url: Optional[str] = None,
**kwargs: Any,
) -> None:
if not startup_nodes:
startup_nodes = []
if "db" in kwargs:
# Argument 'db' is not possible to use in cluster mode
raise RedisClusterException(
"Argument 'db' is not possible to use in cluster mode"
)
# Get the startup node(s)
if url:
url_options = parse_url(url)
if "path" in url_options:
raise RedisClusterException(
"RedisCluster does not currently support Unix Domain "
"Socket connections"
)
if "db" in url_options and url_options["db"] != 0:
# Argument 'db' is not possible to use in cluster mode
raise RedisClusterException(
"A ``db`` querystring option can only be 0 in cluster mode"
)
kwargs.update(url_options)
host = kwargs.get("host")
port = kwargs.get("port", port)
elif (not host or not port) and not startup_nodes:
# No startup node was provided
raise RedisClusterException(
"RedisCluster requires at least one node to discover the "
"cluster. Please provide one of the followings:\n"
"1. host and port, for example:\n"
" RedisCluster(host='localhost', port=6379)\n"
"2. list of startup nodes, for example:\n"
" RedisCluster(startup_nodes=[ClusterNode('localhost', 6379),"
" ClusterNode('localhost', 6378)])"
)
# Update the connection arguments
# Whenever a new connection is established, RedisCluster's on_connect
# method should be run
kwargs["redis_connect_func"] = self.on_connect
self.connection_kwargs = kwargs = cleanup_kwargs(**kwargs)
self.response_callbacks = kwargs[
"response_callbacks"
] = self.__class__.RESPONSE_CALLBACKS.copy()
if host and port:
startup_nodes.append(ClusterNode(host, port, **self.connection_kwargs))
self.nodes_manager = NodesManager(
startup_nodes=startup_nodes,
require_full_coverage=require_full_coverage,
**self.connection_kwargs,
)
self.encoder = Encoder(
kwargs.get("encoding", "utf-8"),
kwargs.get("encoding_errors", "strict"),
kwargs.get("decode_responses", False),
)
self.cluster_error_retry_attempts = cluster_error_retry_attempts
self.read_from_replicas = read_from_replicas
self.reinitialize_steps = reinitialize_steps
self.reinitialize_counter = 0
self.commands_parser = CommandsParser()
self.node_flags = self.__class__.NODE_FLAGS.copy()
self.command_flags = self.__class__.COMMAND_FLAGS.copy()
self.result_callbacks = self.__class__.RESULT_CALLBACKS.copy()
self.result_callbacks[
"CLUSTER SLOTS"
] = lambda cmd, res, **kwargs: parse_cluster_slots(
list(res.values())[0], **kwargs
)
self._initialize = True
self._lock = asyncio.Lock()
async def initialize(self) -> "RedisCluster":
"""Get all nodes from startup nodes & creates connections if not initialized."""
if self._initialize:
async with self._lock:
if self._initialize:
self._initialize = False
try:
await self.nodes_manager.initialize()
await self.commands_parser.initialize(
self.nodes_manager.default_node
)
except BaseException:
self._initialize = True
await self.nodes_manager.close()
await self.nodes_manager.close("startup_nodes")
raise
return self
async def close(self) -> None:
"""Close all connections & client if initialized."""
if not self._initialize:
async with self._lock:
if not self._initialize:
self._initialize = True
await self.nodes_manager.close()
async def __aenter__(self) -> "RedisCluster":
return await self.initialize()
async def __aexit__(self, exc_type: None, exc_value: None, traceback: None) -> None:
await self.close()
def __await__(self) -> Generator[Any, None, "RedisCluster"]:
return self.initialize().__await__()
_DEL_MESSAGE = "Unclosed RedisCluster client"
def __del__(self) -> None:
if hasattr(self, "_initialize") and not self._initialize:
warnings.warn(f"{self._DEL_MESSAGE} {self!r}", ResourceWarning, source=self)
try:
context = {"client": self, "message": self._DEL_MESSAGE}
# TODO: Change to get_running_loop() when dropping support for py3.6
asyncio.get_event_loop().call_exception_handler(context)
except RuntimeError:
...
async def on_connect(self, connection: Connection) -> None:
connection.set_parser(ClusterParser)
await connection.on_connect()
if self.read_from_replicas:
# Sending READONLY command to server to configure connection as
# readonly. Since each cluster node may change its server type due
# to a failover, we should establish a READONLY connection
# regardless of the server type. If this is a primary connection,
# READONLY would not affect executing write commands.
await connection.send_command("READONLY")
if str_if_bytes(await connection.read_response_without_lock()) != "OK":
raise ConnectionError("READONLY command failed")
def get_nodes(self) -> List["ClusterNode"]:
"""Get all nodes of the cluster."""
return list(self.nodes_manager.nodes_cache.values())
def get_primaries(self) -> List["ClusterNode"]:
"""Get the primary nodes of the cluster."""
return self.nodes_manager.get_nodes_by_server_type(PRIMARY)
def get_replicas(self) -> List["ClusterNode"]:
"""Get the replica nodes of the cluster."""
return self.nodes_manager.get_nodes_by_server_type(REPLICA)
def get_random_node(self) -> "ClusterNode":
"""Get a random node of the cluster."""
return random.choice(list(self.nodes_manager.nodes_cache.values()))
def get_default_node(self) -> "ClusterNode":
"""Get the default node of the client."""
return self.nodes_manager.default_node
def set_default_node(self, node: "ClusterNode") -> None:
"""
Set the default node of the client.
:raises DataError: if None is passed or node does not exist in cluster.
"""
if not node or not self.get_node(node_name=node.name):
raise DataError("The requested node does not exist in the cluster.")
self.nodes_manager.default_node = node
def get_node(
self,
host: Optional[str] = None,
port: Optional[int] = None,
node_name: Optional[str] = None,
) -> Optional["ClusterNode"]:
"""Get node by (host, port) or node_name."""
return self.nodes_manager.get_node(host, port, node_name)
def get_node_from_key(
self, key: str, replica: bool = False
) -> Optional["ClusterNode"]:
"""
Get the cluster node corresponding to the provided key.
:param key:
:param replica:
| Indicates if a replica should be returned
|
None will returned if no replica holds this key
:raises SlotNotCoveredError: if the key is not covered by any slot.
"""
slot = self.keyslot(key)
slot_cache = self.nodes_manager.slots_cache.get(slot)
if not slot_cache:
raise SlotNotCoveredError(f'Slot "{slot}" is not covered by the cluster.')
if replica and len(self.nodes_manager.slots_cache[slot]) < 2:
return None
elif replica:
node_idx = 1
else:
# primary
node_idx = 0
return slot_cache[node_idx]
def keyslot(self, key: EncodableT) -> int:
"""
Find the keyslot for a given key.
See: https://redis.io/docs/manual/scaling/#redis-cluster-data-sharding
"""
return key_slot(self.encoder.encode(key))
def get_encoder(self) -> Encoder:
"""Get the encoder object of the client."""
return self.encoder
def get_connection_kwargs(self) -> Dict[str, Optional[Any]]:
"""Get the kwargs passed to :class:`~redis.asyncio.connection.Connection`."""
return self.connection_kwargs
def set_response_callback(self, command: str, callback: ResponseCallbackT) -> None:
"""Set a custom response callback."""
self.response_callbacks[command] = callback
async def _determine_nodes(
self, command: str, *args: Any, node_flag: Optional[str] = None
) -> List["ClusterNode"]:
if not node_flag:
# get the nodes group for this command if it was predefined
node_flag = self.command_flags.get(command)
if node_flag in self.node_flags:
if node_flag == self.__class__.DEFAULT_NODE:
# return the cluster's default node
return [self.nodes_manager.default_node]
if node_flag == self.__class__.PRIMARIES:
# return all primaries
return self.nodes_manager.get_nodes_by_server_type(PRIMARY)
if node_flag == self.__class__.REPLICAS:
# return all replicas
return self.nodes_manager.get_nodes_by_server_type(REPLICA)
if node_flag == self.__class__.ALL_NODES:
# return all nodes
return list(self.nodes_manager.nodes_cache.values())
if node_flag == self.__class__.RANDOM:
# return a random node
return [random.choice(list(self.nodes_manager.nodes_cache.values()))]
# get the node that holds the key's slot
return [
self.nodes_manager.get_node_from_slot(
await self._determine_slot(command, *args),
self.read_from_replicas and command in READ_COMMANDS,
)
]
async def _determine_slot(self, command: str, *args: Any) -> int:
if self.command_flags.get(command) == SLOT_ID:
# The command contains the slot ID
return int(args[0])
# Get the keys in the command
# EVAL and EVALSHA are common enough that it's wasteful to go to the
# redis server to parse the keys. Besides, there is a bug in redis<7.0
# where `self._get_command_keys()` fails anyway. So, we special case
# EVAL/EVALSHA.
# - issue: https://github.com/redis/redis/issues/9493
# - fix: https://github.com/redis/redis/pull/9733
if command in ("EVAL", "EVALSHA"):
# command syntax: EVAL "script body" num_keys ...
if len(args) < 2:
raise RedisClusterException(
f"Invalid args in command: {command, *args}"
)
keys = args[2 : 2 + args[1]]
# if there are 0 keys, that means the script can be run on any node
# so we can just return a random slot
if not keys:
return random.randrange(0, REDIS_CLUSTER_HASH_SLOTS)
else:
keys = await self.commands_parser.get_keys(command, *args)
if not keys:
# FCALL can call a function with 0 keys, that means the function
# can be run on any node so we can just return a random slot
if command in ("FCALL", "FCALL_RO"):
return random.randrange(0, REDIS_CLUSTER_HASH_SLOTS)
raise RedisClusterException(
"No way to dispatch this command to Redis Cluster. "
"Missing key.\nYou can execute the command by specifying "
f"target nodes.\nCommand: {args}"
)
# single key command
if len(keys) == 1:
return self.keyslot(keys[0])
# multi-key command; we need to make sure all keys are mapped to
# the same slot
slots = {self.keyslot(key) for key in keys}
if len(slots) != 1:
raise RedisClusterException(
f"{command} - all keys must map to the same key slot"
)
return slots.pop()
def _is_node_flag(self, target_nodes: Any) -> bool:
return isinstance(target_nodes, str) and target_nodes in self.node_flags
def _parse_target_nodes(self, target_nodes: Any) -> List["ClusterNode"]:
if isinstance(target_nodes, list):
nodes = target_nodes
elif isinstance(target_nodes, ClusterNode):
# Supports passing a single ClusterNode as a variable
nodes = [target_nodes]
elif isinstance(target_nodes, dict):
# Supports dictionaries of the format {node_name: node}.
# It enables to execute commands with multi nodes as follows:
# rc.cluster_save_config(rc.get_primaries())
nodes = list(target_nodes.values())
else:
raise TypeError(
"target_nodes type can be one of the following: "
"node_flag (PRIMARIES, REPLICAS, RANDOM, ALL_NODES),"
"ClusterNode, list<ClusterNode>, or dict<any, ClusterNode>. "
f"The passed type is {type(target_nodes)}"
)
return nodes
async def execute_command(self, *args: EncodableT, **kwargs: Any) -> Any:
"""
Execute a raw command on the appropriate cluster node or target_nodes.
It will retry the command as specified by :attr:`cluster_error_retry_attempts` &
then raise an exception.
:param args:
| Raw command args
:param kwargs:
- target_nodes: :attr:`NODE_FLAGS` or :class:`~.ClusterNode`
or List[:class:`~.ClusterNode`] or Dict[Any, :class:`~.ClusterNode`]
- Rest of the kwargs are passed to the Redis connection
:raises RedisClusterException: if target_nodes is not provided & the command
can't be mapped to a slot
"""
command = args[0]
target_nodes = []
target_nodes_specified = False
retry_attempts = self.cluster_error_retry_attempts
passed_targets = kwargs.pop("target_nodes", None)
if passed_targets and not self._is_node_flag(passed_targets):
target_nodes = self._parse_target_nodes(passed_targets)
target_nodes_specified = True
retry_attempts = 1
for _ in range(retry_attempts):
if self._initialize:
await self.initialize()
try:
if not target_nodes_specified:
# Determine the nodes to execute the command on
target_nodes = await self._determine_nodes(
*args, node_flag=passed_targets
)
if not target_nodes:
raise RedisClusterException(
f"No targets were found to execute {args} command on"
)
if len(target_nodes) == 1:
# Return the processed result
ret = await self._execute_command(target_nodes[0], *args, **kwargs)
if command in self.result_callbacks:
return self.result_callbacks[command](
command, {target_nodes[0].name: ret}, **kwargs
)
return ret
else:
keys = [node.name for node in target_nodes]
values = await asyncio.gather(
*(
asyncio.ensure_future(
self._execute_command(node, *args, **kwargs)
)
for node in target_nodes
)
)
if command in self.result_callbacks:
return self.result_callbacks[command](
command, dict(zip(keys, values)), **kwargs
)
return dict(zip(keys, values))
except BaseException as e:
if type(e) in self.__class__.ERRORS_ALLOW_RETRY:
# The nodes and slots cache were reinitialized.
# Try again with the new cluster setup.
exception = e
else:
# All other errors should be raised.
raise e
# If it fails the configured number of times then raise exception back
# to caller of this method
raise exception
async def _execute_command(
self, target_node: "ClusterNode", *args: Union[KeyT, EncodableT], **kwargs: Any
) -> Any:
asking = moved = False
redirect_addr = None
ttl = self.RedisClusterRequestTTL
connection_error_retry_counter = 0
while ttl > 0:
ttl -= 1
try:
if asking:
target_node = self.get_node(node_name=redirect_addr)
await target_node.execute_command("ASKING")
asking = False
elif moved:
# MOVED occurred and the slots cache was updated,
# refresh the target node
slot = await self._determine_slot(*args)
target_node = self.nodes_manager.get_node_from_slot(
slot, self.read_from_replicas and args[0] in READ_COMMANDS
)
moved = False
return await target_node.execute_command(*args, **kwargs)
except BusyLoadingError:
raise
except (ConnectionError, TimeoutError):
# Give the node 0.25 seconds to get back up and retry again
# with same node and configuration. After 5 attempts then try
# to reinitialize the cluster and see if the nodes
# configuration has changed or not
connection_error_retry_counter += 1
if connection_error_retry_counter < 5:
await asyncio.sleep(0.25)
else:
# Hard force of reinitialize of the node/slots setup
# and try again with the new setup
await self.close()
raise
except MovedError as e:
# First, we will try to patch the slots/nodes cache with the
# redirected node output and try again. If MovedError exceeds
# 'reinitialize_steps' number of times, we will force
# reinitializing the tables, and then try again.
# 'reinitialize_steps' counter will increase faster when
# the same client object is shared between multiple threads. To
# reduce the frequency you can set this variable in the
# RedisCluster constructor.
self.reinitialize_counter += 1
if (
self.reinitialize_steps
and self.reinitialize_counter % self.reinitialize_steps == 0
):
await self.close()
# Reset the counter
self.reinitialize_counter = 0
else:
self.nodes_manager._moved_exception = e
moved = True
except TryAgainError:
if ttl < self.RedisClusterRequestTTL / 2:
await asyncio.sleep(0.05)
except AskError as e:
redirect_addr = get_node_name(host=e.host, port=e.port)
asking = True
except ClusterDownError:
# ClusterDownError can occur during a failover and to get
# self-healed, we will try to reinitialize the cluster layout
# and retry executing the command
await asyncio.sleep(0.25)
await self.close()
raise
raise ClusterError("TTL exhausted.")
def pipeline(
self, transaction: Optional[Any] = None, shard_hint: Optional[Any] = None
) -> "ClusterPipeline":
"""
Create & return a new :class:`~.ClusterPipeline` object.
Cluster implementation of pipeline does not support transaction or shard_hint.
:raises RedisClusterException: if transaction or shard_hint are truthy values
"""
if shard_hint:
raise RedisClusterException("shard_hint is deprecated in cluster mode")
if transaction:
raise RedisClusterException("transaction is deprecated in cluster mode")
return ClusterPipeline(self)
class ClusterNode:
"""
Create a new ClusterNode.
Each ClusterNode manages multiple :class:`~redis.asyncio.connection.Connection`
objects for the (host, port).
"""
__slots__ = (
"_command_stack",
"_connections",
"_free",
"connection_class",
"connection_kwargs",
"host",
"max_connections",
"name",
"port",
"response_callbacks",
"server_type",
)
def __init__(
self,
host: str,
port: int,
server_type: Optional[str] = None,
max_connections: int = 2**31,
connection_class: Type[Connection] = Connection,
**connection_kwargs: Any,
) -> None:
if host == "localhost":
host = socket.gethostbyname(host)
connection_kwargs["host"] = host
connection_kwargs["port"] = port
self.host = host
self.port = port
self.name = get_node_name(host, port)
self.server_type = server_type
self.max_connections = max_connections
self.connection_class = connection_class
self.connection_kwargs = connection_kwargs
self.response_callbacks = connection_kwargs.pop(
"response_callbacks", RedisCluster.RESPONSE_CALLBACKS
)
self._connections: List[Connection] = []
self._free: Deque[Connection] = collections.deque(maxlen=self.max_connections)
self._command_stack: List["PipelineCommand"] = []
def __repr__(self) -> str:
return (
f"[host={self.host}, port={self.port}, "
f"name={self.name}, server_type={self.server_type}]"
)
def __eq__(self, obj: Any) -> bool:
return isinstance(obj, ClusterNode) and obj.name == self.name
_DEL_MESSAGE = "Unclosed ClusterNode object"
def __del__(self) -> None:
for connection in self._connections:
if connection.is_connected:
warnings.warn(
f"{self._DEL_MESSAGE} {self!r}", ResourceWarning, source=self
)
try:
context = {"client": self, "message": self._DEL_MESSAGE}
# TODO: Change to get_running_loop() when dropping support for py3.6
asyncio.get_event_loop().call_exception_handler(context)
except RuntimeError:
...
break
async def disconnect(self) -> None:
ret = await asyncio.gather(
*(
asyncio.ensure_future(connection.disconnect())
for connection in self._connections
),
return_exceptions=True,
)
exc = next((res for res in ret if isinstance(res, Exception)), None)
if exc:
raise exc
def acquire_connection(self) -> Connection:
if self._free:
for _ in range(len(self._free)):
connection = self._free.popleft()
if connection.is_connected:
return connection
self._free.append(connection)
return self._free.popleft()
if len(self._connections) < self.max_connections:
connection = self.connection_class(**self.connection_kwargs)
self._connections.append(connection)
return connection
raise ConnectionError("Too many connections")
async def parse_response(
self, connection: Connection, command: str, **kwargs: Any
) -> Any:
try:
if NEVER_DECODE in kwargs:
response = await connection.read_response_without_lock(
disable_decoding=True
)
else:
response = await connection.read_response_without_lock()
except ResponseError:
if EMPTY_RESPONSE in kwargs:
return kwargs[EMPTY_RESPONSE]
raise
# Return response
if command in self.response_callbacks:
return self.response_callbacks[command](response, **kwargs)
return response
async def execute_command(self, *args: Any, **kwargs: Any) -> Any:
# Acquire connection
connection = self.acquire_connection()
# Execute command
await connection.send_packed_command(connection.pack_command(*args), False)
# Read response
try:
return await self.parse_response(connection, args[0], **kwargs)
finally:
# Release connection
self._free.append(connection)
async def execute_pipeline(self) -> bool:
# Acquire connection
connection = self.acquire_connection()
# Execute command
await connection.send_packed_command(
connection.pack_commands(cmd.args for cmd in self._command_stack), False
)
# Read responses
ret = False
for cmd in self._command_stack:
try:
cmd.result = await self.parse_response(
connection, cmd.args[0], **cmd.kwargs
)
except Exception as e:
cmd.result = e
ret = True
# Release connection
self._free.append(connection)
return ret
class NodesManager:
__slots__ = (
"_moved_exception",
"connection_kwargs",
"default_node",
"nodes_cache",
"read_load_balancer",
"require_full_coverage",
"slots_cache",
"startup_nodes",
)
def __init__(
self,
startup_nodes: List["ClusterNode"],
require_full_coverage: bool = False,
**kwargs: Any,
) -> None:
self.startup_nodes = {node.name: node for node in startup_nodes}
self.require_full_coverage = require_full_coverage
self.connection_kwargs = kwargs
self.default_node: "ClusterNode" = None
self.nodes_cache: Dict[str, "ClusterNode"] = {}
self.slots_cache: Dict[int, List["ClusterNode"]] = {}
self.read_load_balancer = LoadBalancer()
self._moved_exception: MovedError = None
def get_node(
self,
host: Optional[str] = None,
port: Optional[int] = None,
node_name: Optional[str] = None,
) -> Optional["ClusterNode"]:
if host and port:
# the user passed host and port
if host == "localhost":
host = socket.gethostbyname(host)
return self.nodes_cache.get(get_node_name(host=host, port=port))
elif node_name:
return self.nodes_cache.get(node_name)
else:
raise DataError(
"get_node requires one of the following: "
"1. node name "
"2. host and port"
)
def set_nodes(
self,
old: Dict[str, "ClusterNode"],
new: Dict[str, "ClusterNode"],
remove_old: bool = False,
) -> None:
if remove_old:
for name in list(old.keys()):
if name not in new:
asyncio.ensure_future(old.pop(name).disconnect())
for name, node in new.items():
if name in old:
if old[name] is node:
continue
asyncio.ensure_future(old[name].disconnect())
old[name] = node
def _update_moved_slots(self) -> None:
e = self._moved_exception
redirected_node = self.get_node(host=e.host, port=e.port)
if redirected_node:
# The node already exists
if redirected_node.server_type != PRIMARY:
# Update the node's server type
redirected_node.server_type = PRIMARY
else:
# This is a new node, we will add it to the nodes cache
redirected_node = ClusterNode(
e.host, e.port, PRIMARY, **self.connection_kwargs
)
self.set_nodes(self.nodes_cache, {redirected_node.name: redirected_node})
if redirected_node in self.slots_cache[e.slot_id]:
# The MOVED error resulted from a failover, and the new slot owner
# had previously been a replica.
old_primary = self.slots_cache[e.slot_id][0]
# Update the old primary to be a replica and add it to the end of
# the slot's node list
old_primary.server_type = REPLICA
self.slots_cache[e.slot_id].append(old_primary)
# Remove the old replica, which is now a primary, from the slot's
# node list
self.slots_cache[e.slot_id].remove(redirected_node)
# Override the old primary with the new one
self.slots_cache[e.slot_id][0] = redirected_node
if self.default_node == old_primary:
# Update the default node with the new primary
self.default_node = redirected_node
else:
# The new slot owner is a new server, or a server from a different
# shard. We need to remove all current nodes from the slot's list
# (including replications) and add just the new node.
self.slots_cache[e.slot_id] = [redirected_node]
# Reset moved_exception
self._moved_exception = None
def get_node_from_slot(
self, slot: int, read_from_replicas: bool = False
) -> "ClusterNode":
if self._moved_exception:
self._update_moved_slots()
try:
if read_from_replicas:
# get the server index in a Round-Robin manner
primary_name = self.slots_cache[slot][0].name
node_idx = self.read_load_balancer.get_server_index(
primary_name, len(self.slots_cache[slot])
)
return self.slots_cache[slot][node_idx]
return self.slots_cache[slot][0]
except (IndexError, TypeError):
raise SlotNotCoveredError(
f'Slot "{slot}" not covered by the cluster. '
f'"require_full_coverage={self.require_full_coverage}"'
)
def get_nodes_by_server_type(self, server_type: str) -> List["ClusterNode"]:
return [
node
for node in self.nodes_cache.values()
if node.server_type == server_type
]
async def initialize(self) -> None:
self.read_load_balancer.reset()
tmp_nodes_cache: Dict[str, "ClusterNode"] = {}
tmp_slots: Dict[int, List["ClusterNode"]] = {}
disagreements = []
startup_nodes_reachable = False
fully_covered = False
for startup_node in self.startup_nodes.values():
try:
# Make sure cluster mode is enabled on this node
if not (await startup_node.execute_command("INFO")).get(
"cluster_enabled"
):
raise RedisClusterException(
"Cluster mode is not enabled on this node"
)
cluster_slots = await startup_node.execute_command("CLUSTER SLOTS")
startup_nodes_reachable = True
except (ConnectionError, TimeoutError):
continue
except ResponseError as e:
# Isn't a cluster connection, so it won't parse these
# exceptions automatically
message = e.__str__()
if "CLUSTERDOWN" in message or "MASTERDOWN" in message:
continue
else:
raise RedisClusterException(
'ERROR sending "cluster slots" command to redis '
f"server: {startup_node}. error: {message}"
)
except Exception as e:
message = e.__str__()
raise RedisClusterException(
'ERROR sending "cluster slots" command to redis '
f"server {startup_node.name}. error: {message}"
)
# CLUSTER SLOTS command results in the following output:
# [[slot_section[from_slot,to_slot,master,replica1,...,replicaN]]]
# where each node contains the following list: [IP, port, node_id]
# Therefore, cluster_slots[0][2][0] will be the IP address of the
# primary node of the first slot section.
# If there's only one server in the cluster, its ``host`` is ''
# Fix it to the host in startup_nodes
if (
len(cluster_slots) == 1
and not cluster_slots[0][2][0]
and len(self.startup_nodes) == 1
):
cluster_slots[0][2][0] = startup_node.host
for slot in cluster_slots:
for i in range(2, len(slot)):
slot[i] = [str_if_bytes(val) for val in slot[i]]
primary_node = slot[2]
host = primary_node[0]
if host == "":
host = startup_node.host
port = int(primary_node[1])
target_node = tmp_nodes_cache.get(get_node_name(host, port))
if not target_node:
target_node = ClusterNode(
host, port, PRIMARY, **self.connection_kwargs
)
# add this node to the nodes cache
tmp_nodes_cache[target_node.name] = target_node
for i in range(int(slot[0]), int(slot[1]) + 1):
if i not in tmp_slots:
tmp_slots[i] = []
tmp_slots[i].append(target_node)
replica_nodes = [slot[j] for j in range(3, len(slot))]
for replica_node in replica_nodes:
host = replica_node[0]
port = replica_node[1]
target_replica_node = tmp_nodes_cache.get(
get_node_name(host, port)
)
if not target_replica_node:
target_replica_node = ClusterNode(
host, port, REPLICA, **self.connection_kwargs
)
tmp_slots[i].append(target_replica_node)
# add this node to the nodes cache
tmp_nodes_cache[
target_replica_node.name
] = target_replica_node
else:
# Validate that 2 nodes want to use the same slot cache
# setup
tmp_slot = tmp_slots[i][0]
if tmp_slot.name != target_node.name:
disagreements.append(
f"{tmp_slot.name} vs {target_node.name} on slot: {i}"
)
if len(disagreements) > 5:
raise RedisClusterException(
f"startup_nodes could not agree on a valid "
f'slots cache: {", ".join(disagreements)}'
)
# Validate if all slots are covered or if we should try next startup node
fully_covered = True
for i in range(REDIS_CLUSTER_HASH_SLOTS):
if i not in tmp_slots:
fully_covered = False
break
if fully_covered:
break
if not startup_nodes_reachable:
raise RedisClusterException(
"Redis Cluster cannot be connected. Please provide at least "
"one reachable node. "
)
# Check if the slots are not fully covered
if not fully_covered and self.require_full_coverage:
# Despite the requirement that the slots be covered, there
# isn't a full coverage
raise RedisClusterException(
f"All slots are not covered after query all startup_nodes. "
f"{len(tmp_slots)} of {REDIS_CLUSTER_HASH_SLOTS} "
f"covered..."
)
# Set the tmp variables to the real variables
self.slots_cache = tmp_slots
self.set_nodes(self.nodes_cache, tmp_nodes_cache, remove_old=True)
# Populate the startup nodes with all discovered nodes
self.set_nodes(self.startup_nodes, self.nodes_cache, remove_old=True)
# Set the default node
self.default_node = self.get_nodes_by_server_type(PRIMARY)[0]
# If initialize was called after a MovedError, clear it
self._moved_exception = None
async def close(self, attr: str = "nodes_cache") -> None:
self.default_node = None
await asyncio.gather(
*(
asyncio.ensure_future(node.disconnect())
for node in getattr(self, attr).values()
)
)
class ClusterPipeline(AbstractRedis, AbstractRedisCluster, AsyncRedisClusterCommands):
"""
Create a new ClusterPipeline object.
Usage::
result = await (
rc.pipeline()
.set("A", 1)
.get("A")
.hset("K", "F", "V")
.hgetall("K")
.mset_nonatomic({"A": 2, "B": 3})
.get("A")
.get("B")
.delete("A", "B", "K")
.execute()
)
# result = [True, "1", 1, {"F": "V"}, True, True, "2", "3", 1, 1, 1]
Note: For commands `DELETE`, `EXISTS`, `TOUCH`, `UNLINK`, `mset_nonatomic`, which
are split across multiple nodes, you'll get multiple results for them in the array.
Retryable errors:
- :class:`~.ClusterDownError`
- :class:`~.ConnectionError`
- :class:`~.TimeoutError`
Redirection errors:
- :class:`~.TryAgainError`
- :class:`~.MovedError`
- :class:`~.AskError`
:param client:
| Existing :class:`~.RedisCluster` client
"""
__slots__ = ("_command_stack", "_client")
def __init__(self, client: RedisCluster) -> None:
self._client = client
self._command_stack: List["PipelineCommand"] = []
async def initialize(self) -> "ClusterPipeline":
if self._client._initialize:
await self._client.initialize()
self._command_stack = []
return self
async def __aenter__(self) -> "ClusterPipeline":
return await self.initialize()
async def __aexit__(self, exc_type: None, exc_value: None, traceback: None) -> None:
self._command_stack = []
def __await__(self) -> Generator[Any, None, "ClusterPipeline"]:
return self.initialize().__await__()
def __enter__(self) -> "ClusterPipeline":
self._command_stack = []
return self
def __exit__(self, exc_type: None, exc_value: None, traceback: None) -> None:
self._command_stack = []
def __bool__(self) -> bool:
return bool(self._command_stack)
def __len__(self) -> int:
return len(self._command_stack)
def execute_command(
self, *args: Union[KeyT, EncodableT], **kwargs: Any
) -> "ClusterPipeline":
"""
Append a raw command to the pipeline.
:param args:
| Raw command args
:param kwargs:
- target_nodes: :attr:`NODE_FLAGS` or :class:`~.ClusterNode`
or List[:class:`~.ClusterNode`] or Dict[Any, :class:`~.ClusterNode`]
- Rest of the kwargs are passed to the Redis connection
"""
self._command_stack.append(
PipelineCommand(len(self._command_stack), *args, **kwargs)
)
return self
async def execute(
self, raise_on_error: bool = True, allow_redirections: bool = True
) -> List[Any]:
"""
Execute the pipeline.
It will retry the commands as specified by :attr:`cluster_error_retry_attempts`
& then raise an exception.
:param raise_on_error:
| Raise the first error if there are any errors
:param allow_redirections:
| Whether to retry each failed command individually in case of redirection
errors
:raises RedisClusterException: if target_nodes is not provided & the command
can't be mapped to a slot
"""
if not self._command_stack:
return []
try:
for _ in range(self._client.cluster_error_retry_attempts):
if self._client._initialize:
await self._client.initialize()
try:
return await self._execute(
self._client,
self._command_stack,
raise_on_error=raise_on_error,
allow_redirections=allow_redirections,
)
except BaseException as e:
if type(e) in self.__class__.ERRORS_ALLOW_RETRY:
# Try again with the new cluster setup.
exception = e
await self._client.close()
await asyncio.sleep(0.25)
else:
# All other errors should be raised.
raise e
# If it fails the configured number of times then raise an exception
raise exception
finally:
self._command_stack = []
async def _execute(
self,
client: "RedisCluster",
stack: List["PipelineCommand"],
raise_on_error: bool = True,
allow_redirections: bool = True,
) -> List[Any]:
todo = [
cmd for cmd in stack if not cmd.result or isinstance(cmd.result, Exception)
]
nodes = {}
for cmd in todo:
target_nodes = await client._determine_nodes(*cmd.args)
if not target_nodes:
raise RedisClusterException(
f"No targets were found to execute {cmd.args} command on"
)
if len(target_nodes) > 1:
raise RedisClusterException(f"Too many targets for command {cmd.args}")
node = target_nodes[0]
if node.name not in nodes:
nodes[node.name] = node
node._command_stack = []
node._command_stack.append(cmd)
errors = await asyncio.gather(
*(asyncio.ensure_future(node.execute_pipeline()) for node in nodes.values())
)
if any(errors):
if allow_redirections:
# send each errored command individually
for cmd in todo:
if isinstance(cmd.result, (TryAgainError, MovedError, AskError)):
try:
cmd.result = await client.execute_command(
*cmd.args, **cmd.kwargs
)
except Exception as e:
cmd.result = e
if raise_on_error:
for cmd in todo:
result = cmd.result
if isinstance(result, Exception):
command = " ".join(map(safe_str, cmd.args))
msg = (
f"Command # {cmd.position + 1} ({command}) of pipeline "
f"caused error: {result.args}"
)
result.args = (msg,) + result.args[1:]
raise result
return [cmd.result for cmd in stack]
def _split_command_across_slots(
self, command: str, *keys: KeyT
) -> "ClusterPipeline":
for slot_keys in self._client._partition_keys_by_slot(keys).values():
self.execute_command(command, *slot_keys)
return self
def mset_nonatomic(
self, mapping: Mapping[AnyKeyT, EncodableT]
) -> "ClusterPipeline":
encoder = self._client.encoder
slots_pairs = {}
for pair in mapping.items():
slot = key_slot(encoder.encode(pair[0]))
slots_pairs.setdefault(slot, []).extend(pair)
for pairs in slots_pairs.values():
self.execute_command("MSET", *pairs)
return self
for command in PIPELINE_BLOCKED_COMMANDS:
command = command.replace(" ", "_").lower()
if command == "mset_nonatomic":
continue
setattr(ClusterPipeline, command, block_pipeline_command(command))
class PipelineCommand:
def __init__(self, position: int, *args: Any, **kwargs: Any) -> None:
self.args = args
self.kwargs = kwargs
self.position = position
self.result: Union[Any, Exception] = None
def __repr__(self) -> str:
return f"[{self.position}] {self.args} ({self.kwargs})"