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- import copy
- import re
- import threading
- import time
- import warnings
- from itertools import chain
- from typing import Any, Callable, Dict, List, Optional, Type, Union
- from redis._parsers.encoders import Encoder
- from redis._parsers.helpers import (
- _RedisCallbacks,
- _RedisCallbacksRESP2,
- _RedisCallbacksRESP3,
- bool_ok,
- )
- from redis.commands import (
- CoreCommands,
- RedisModuleCommands,
- SentinelCommands,
- list_or_args,
- )
- from redis.connection import (
- AbstractConnection,
- ConnectionPool,
- SSLConnection,
- UnixDomainSocketConnection,
- )
- from redis.credentials import CredentialProvider
- from redis.exceptions import (
- ConnectionError,
- ExecAbortError,
- PubSubError,
- RedisError,
- ResponseError,
- TimeoutError,
- WatchError,
- )
- from redis.lock import Lock
- from redis.retry import Retry
- from redis.utils import (
- HIREDIS_AVAILABLE,
- _set_info_logger,
- get_lib_version,
- safe_str,
- str_if_bytes,
- )
- SYM_EMPTY = b""
- EMPTY_RESPONSE = "EMPTY_RESPONSE"
- # some responses (ie. dump) are binary, and just meant to never be decoded
- NEVER_DECODE = "NEVER_DECODE"
- class CaseInsensitiveDict(dict):
- "Case insensitive dict implementation. Assumes string keys only."
- def __init__(self, data: Dict[str, str]) -> None:
- for k, v in data.items():
- self[k.upper()] = v
- def __contains__(self, k):
- return super().__contains__(k.upper())
- def __delitem__(self, k):
- super().__delitem__(k.upper())
- def __getitem__(self, k):
- return super().__getitem__(k.upper())
- def get(self, k, default=None):
- return super().get(k.upper(), default)
- def __setitem__(self, k, v):
- super().__setitem__(k.upper(), v)
- def update(self, data):
- data = CaseInsensitiveDict(data)
- super().update(data)
- class AbstractRedis:
- pass
- class Redis(RedisModuleCommands, CoreCommands, SentinelCommands):
- """
- Implementation of the Redis protocol.
- This abstract class provides a Python interface to all Redis commands
- and an implementation of the Redis protocol.
- Pipelines derive from this, implementing how
- the commands are sent and received to the Redis server. Based on
- configuration, an instance will either use a ConnectionPool, or
- Connection object to talk to redis.
- It is not safe to pass PubSub or Pipeline objects between threads.
- """
- @classmethod
- def from_url(cls, url: str, **kwargs) -> "Redis":
- """
- 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@]/path/to/socket.sock?db=0[&password=password]
- 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 the ``ConnectionPool``'s
- class initializer. In the case of conflicting arguments, querystring
- arguments always win.
- """
- single_connection_client = kwargs.pop("single_connection_client", False)
- connection_pool = ConnectionPool.from_url(url, **kwargs)
- client = cls(
- connection_pool=connection_pool,
- single_connection_client=single_connection_client,
- )
- client.auto_close_connection_pool = True
- return client
- @classmethod
- def from_pool(
- cls: Type["Redis"],
- connection_pool: ConnectionPool,
- ) -> "Redis":
- """
- Return a Redis client from the given connection pool.
- The Redis client will take ownership of the connection pool and
- close it when the Redis client is closed.
- """
- client = cls(
- connection_pool=connection_pool,
- )
- client.auto_close_connection_pool = True
- return client
- def __init__(
- self,
- host="localhost",
- port=6379,
- db=0,
- password=None,
- socket_timeout=None,
- socket_connect_timeout=None,
- socket_keepalive=None,
- socket_keepalive_options=None,
- connection_pool=None,
- unix_socket_path=None,
- encoding="utf-8",
- encoding_errors="strict",
- charset=None,
- errors=None,
- decode_responses=False,
- retry_on_timeout=False,
- retry_on_error=None,
- ssl=False,
- ssl_keyfile=None,
- ssl_certfile=None,
- ssl_cert_reqs="required",
- ssl_ca_certs=None,
- ssl_ca_path=None,
- ssl_ca_data=None,
- ssl_check_hostname=False,
- ssl_password=None,
- ssl_validate_ocsp=False,
- ssl_validate_ocsp_stapled=False,
- ssl_ocsp_context=None,
- ssl_ocsp_expected_cert=None,
- ssl_min_version=None,
- ssl_ciphers=None,
- max_connections=None,
- single_connection_client=False,
- health_check_interval=0,
- client_name=None,
- lib_name="redis-py",
- lib_version=get_lib_version(),
- username=None,
- retry=None,
- redis_connect_func=None,
- credential_provider: Optional[CredentialProvider] = None,
- protocol: Optional[int] = 2,
- ) -> None:
- """
- Initialize a new Redis client.
- To specify a retry policy for specific errors, first set
- `retry_on_error` to a list of the error/s to retry on, then set
- `retry` to a valid `Retry` object.
- To retry on TimeoutError, `retry_on_timeout` can also be set to `True`.
- Args:
- single_connection_client:
- if `True`, connection pool is not used. In that case `Redis`
- instance use is not thread safe.
- """
- if not connection_pool:
- if charset is not None:
- warnings.warn(
- DeprecationWarning(
- '"charset" is deprecated. Use "encoding" instead'
- )
- )
- encoding = charset
- if errors is not None:
- warnings.warn(
- DeprecationWarning(
- '"errors" is deprecated. Use "encoding_errors" instead'
- )
- )
- encoding_errors = errors
- if not retry_on_error:
- retry_on_error = []
- if retry_on_timeout is True:
- retry_on_error.append(TimeoutError)
- kwargs = {
- "db": db,
- "username": username,
- "password": password,
- "socket_timeout": socket_timeout,
- "encoding": encoding,
- "encoding_errors": encoding_errors,
- "decode_responses": decode_responses,
- "retry_on_error": retry_on_error,
- "retry": copy.deepcopy(retry),
- "max_connections": max_connections,
- "health_check_interval": health_check_interval,
- "client_name": client_name,
- "lib_name": lib_name,
- "lib_version": lib_version,
- "redis_connect_func": redis_connect_func,
- "credential_provider": credential_provider,
- "protocol": protocol,
- }
- # based on input, setup appropriate connection args
- if unix_socket_path is not None:
- kwargs.update(
- {
- "path": unix_socket_path,
- "connection_class": UnixDomainSocketConnection,
- }
- )
- else:
- # TCP specific options
- kwargs.update(
- {
- "host": host,
- "port": port,
- "socket_connect_timeout": socket_connect_timeout,
- "socket_keepalive": socket_keepalive,
- "socket_keepalive_options": socket_keepalive_options,
- }
- )
- if ssl:
- kwargs.update(
- {
- "connection_class": SSLConnection,
- "ssl_keyfile": ssl_keyfile,
- "ssl_certfile": ssl_certfile,
- "ssl_cert_reqs": ssl_cert_reqs,
- "ssl_ca_certs": ssl_ca_certs,
- "ssl_ca_data": ssl_ca_data,
- "ssl_check_hostname": ssl_check_hostname,
- "ssl_password": ssl_password,
- "ssl_ca_path": ssl_ca_path,
- "ssl_validate_ocsp_stapled": ssl_validate_ocsp_stapled,
- "ssl_validate_ocsp": ssl_validate_ocsp,
- "ssl_ocsp_context": ssl_ocsp_context,
- "ssl_ocsp_expected_cert": ssl_ocsp_expected_cert,
- "ssl_min_version": ssl_min_version,
- "ssl_ciphers": ssl_ciphers,
- }
- )
- connection_pool = ConnectionPool(**kwargs)
- self.auto_close_connection_pool = True
- else:
- self.auto_close_connection_pool = False
- self.connection_pool = connection_pool
- self.connection = None
- if single_connection_client:
- self.connection = self.connection_pool.get_connection("_")
- self.response_callbacks = CaseInsensitiveDict(_RedisCallbacks)
- if self.connection_pool.connection_kwargs.get("protocol") in ["3", 3]:
- self.response_callbacks.update(_RedisCallbacksRESP3)
- else:
- self.response_callbacks.update(_RedisCallbacksRESP2)
- def __repr__(self) -> str:
- return (
- f"<{type(self).__module__}.{type(self).__name__}"
- f"({repr(self.connection_pool)})>"
- )
- def get_encoder(self) -> "Encoder":
- """Get the connection pool's encoder"""
- return self.connection_pool.get_encoder()
- def get_connection_kwargs(self) -> Dict:
- """Get the connection's key-word arguments"""
- return self.connection_pool.connection_kwargs
- def get_retry(self) -> Optional["Retry"]:
- return self.get_connection_kwargs().get("retry")
- def set_retry(self, retry: "Retry") -> None:
- self.get_connection_kwargs().update({"retry": retry})
- self.connection_pool.set_retry(retry)
- def set_response_callback(self, command: str, callback: Callable) -> None:
- """Set a custom Response Callback"""
- self.response_callbacks[command] = callback
- def load_external_module(self, funcname, func) -> None:
- """
- This function can be used to add externally defined redis modules,
- and their namespaces to the redis client.
- funcname - A string containing the name of the function to create
- func - The function, being added to this class.
- ex: Assume that one has a custom redis module named foomod that
- creates command named 'foo.dothing' and 'foo.anotherthing' in redis.
- To load function functions into this namespace:
- from redis import Redis
- from foomodule import F
- r = Redis()
- r.load_external_module("foo", F)
- r.foo().dothing('your', 'arguments')
- For a concrete example see the reimport of the redisjson module in
- tests/test_connection.py::test_loading_external_modules
- """
- setattr(self, funcname, func)
- def pipeline(self, transaction=True, shard_hint=None) -> "Pipeline":
- """
- Return a new pipeline object that can queue multiple commands for
- later execution. ``transaction`` indicates whether all commands
- should be executed atomically. Apart from making a group of operations
- atomic, pipelines are useful for reducing the back-and-forth overhead
- between the client and server.
- """
- return Pipeline(
- self.connection_pool, self.response_callbacks, transaction, shard_hint
- )
- def transaction(
- self, func: Callable[["Pipeline"], None], *watches, **kwargs
- ) -> None:
- """
- Convenience method for executing the callable `func` as a transaction
- while watching all keys specified in `watches`. The 'func' callable
- should expect a single argument which is a Pipeline object.
- """
- shard_hint = kwargs.pop("shard_hint", None)
- value_from_callable = kwargs.pop("value_from_callable", False)
- watch_delay = kwargs.pop("watch_delay", None)
- with self.pipeline(True, shard_hint) as pipe:
- while True:
- try:
- if watches:
- pipe.watch(*watches)
- func_value = func(pipe)
- exec_value = pipe.execute()
- return func_value if value_from_callable else exec_value
- except WatchError:
- if watch_delay is not None and watch_delay > 0:
- time.sleep(watch_delay)
- continue
- def lock(
- self,
- name: str,
- timeout: Optional[float] = None,
- sleep: float = 0.1,
- blocking: bool = True,
- blocking_timeout: Optional[float] = None,
- lock_class: Union[None, Any] = None,
- thread_local: bool = True,
- ):
- """
- Return a new Lock object using key ``name`` that mimics
- the behavior of threading.Lock.
- If specified, ``timeout`` indicates a maximum life for the lock.
- By default, it will remain locked until release() is called.
- ``sleep`` indicates the amount of time to sleep per loop iteration
- when the lock is in blocking mode and another client is currently
- holding the lock.
- ``blocking`` indicates whether calling ``acquire`` should block until
- the lock has been acquired or to fail immediately, causing ``acquire``
- to return False and the lock not being acquired. Defaults to True.
- Note this value can be overridden by passing a ``blocking``
- argument to ``acquire``.
- ``blocking_timeout`` indicates the maximum amount of time in seconds to
- spend trying to acquire the lock. A value of ``None`` indicates
- continue trying forever. ``blocking_timeout`` can be specified as a
- float or integer, both representing the number of seconds to wait.
- ``lock_class`` forces the specified lock implementation. Note that as
- of redis-py 3.0, the only lock class we implement is ``Lock`` (which is
- a Lua-based lock). So, it's unlikely you'll need this parameter, unless
- you have created your own custom lock class.
- ``thread_local`` indicates whether the lock token is placed in
- thread-local storage. By default, the token is placed in thread local
- storage so that a thread only sees its token, not a token set by
- another thread. Consider the following timeline:
- time: 0, thread-1 acquires `my-lock`, with a timeout of 5 seconds.
- thread-1 sets the token to "abc"
- time: 1, thread-2 blocks trying to acquire `my-lock` using the
- Lock instance.
- time: 5, thread-1 has not yet completed. redis expires the lock
- key.
- time: 5, thread-2 acquired `my-lock` now that it's available.
- thread-2 sets the token to "xyz"
- time: 6, thread-1 finishes its work and calls release(). if the
- token is *not* stored in thread local storage, then
- thread-1 would see the token value as "xyz" and would be
- able to successfully release the thread-2's lock.
- In some use cases it's necessary to disable thread local storage. For
- example, if you have code where one thread acquires a lock and passes
- that lock instance to a worker thread to release later. If thread
- local storage isn't disabled in this case, the worker thread won't see
- the token set by the thread that acquired the lock. Our assumption
- is that these cases aren't common and as such default to using
- thread local storage."""
- if lock_class is None:
- lock_class = Lock
- return lock_class(
- self,
- name,
- timeout=timeout,
- sleep=sleep,
- blocking=blocking,
- blocking_timeout=blocking_timeout,
- thread_local=thread_local,
- )
- def pubsub(self, **kwargs):
- """
- Return a Publish/Subscribe object. With this object, you can
- subscribe to channels and listen for messages that get published to
- them.
- """
- return PubSub(self.connection_pool, **kwargs)
- def monitor(self):
- return Monitor(self.connection_pool)
- def client(self):
- return self.__class__(
- connection_pool=self.connection_pool, single_connection_client=True
- )
- def __enter__(self):
- return self
- def __exit__(self, exc_type, exc_value, traceback):
- self.close()
- def __del__(self):
- self.close()
- def close(self):
- # In case a connection property does not yet exist
- # (due to a crash earlier in the Redis() constructor), return
- # immediately as there is nothing to clean-up.
- if not hasattr(self, "connection"):
- return
- conn = self.connection
- if conn:
- self.connection = None
- self.connection_pool.release(conn)
- if self.auto_close_connection_pool:
- self.connection_pool.disconnect()
- def _send_command_parse_response(self, conn, command_name, *args, **options):
- """
- Send a command and parse the response
- """
- conn.send_command(*args)
- return self.parse_response(conn, command_name, **options)
- def _disconnect_raise(self, conn, error):
- """
- Close the connection and raise an exception
- if retry_on_error is not set or the error
- is not one of the specified error types
- """
- conn.disconnect()
- if (
- conn.retry_on_error is None
- or isinstance(error, tuple(conn.retry_on_error)) is False
- ):
- raise error
- # COMMAND EXECUTION AND PROTOCOL PARSING
- def execute_command(self, *args, **options):
- """Execute a command and return a parsed response"""
- pool = self.connection_pool
- command_name = args[0]
- conn = self.connection or pool.get_connection(command_name, **options)
- try:
- return conn.retry.call_with_retry(
- lambda: self._send_command_parse_response(
- conn, command_name, *args, **options
- ),
- lambda error: self._disconnect_raise(conn, error),
- )
- finally:
- if not self.connection:
- pool.release(conn)
- def parse_response(self, connection, command_name, **options):
- """Parses a response from the Redis server"""
- try:
- if NEVER_DECODE in options:
- response = connection.read_response(disable_decoding=True)
- options.pop(NEVER_DECODE)
- else:
- response = connection.read_response()
- except ResponseError:
- if EMPTY_RESPONSE in options:
- return options[EMPTY_RESPONSE]
- raise
- if EMPTY_RESPONSE in options:
- options.pop(EMPTY_RESPONSE)
- if command_name in self.response_callbacks:
- return self.response_callbacks[command_name](response, **options)
- return response
- StrictRedis = Redis
- class Monitor:
- """
- Monitor is useful for handling the MONITOR command to the redis server.
- next_command() method returns one command from monitor
- listen() method yields commands from monitor.
- """
- monitor_re = re.compile(r"\[(\d+) (.*?)\] (.*)")
- command_re = re.compile(r'"(.*?)(?<!\\)"')
- def __init__(self, connection_pool):
- self.connection_pool = connection_pool
- self.connection = self.connection_pool.get_connection("MONITOR")
- def __enter__(self):
- self.connection.send_command("MONITOR")
- # check that monitor returns 'OK', but don't return it to user
- response = self.connection.read_response()
- if not bool_ok(response):
- raise RedisError(f"MONITOR failed: {response}")
- return self
- def __exit__(self, *args):
- self.connection.disconnect()
- self.connection_pool.release(self.connection)
- def next_command(self):
- """Parse the response from a monitor command"""
- response = self.connection.read_response()
- if isinstance(response, bytes):
- response = self.connection.encoder.decode(response, force=True)
- command_time, command_data = response.split(" ", 1)
- m = self.monitor_re.match(command_data)
- db_id, client_info, command = m.groups()
- command = " ".join(self.command_re.findall(command))
- # Redis escapes double quotes because each piece of the command
- # string is surrounded by double quotes. We don't have that
- # requirement so remove the escaping and leave the quote.
- command = command.replace('\\"', '"')
- if client_info == "lua":
- client_address = "lua"
- client_port = ""
- client_type = "lua"
- elif client_info.startswith("unix"):
- client_address = "unix"
- client_port = client_info[5:]
- client_type = "unix"
- else:
- # use rsplit as ipv6 addresses contain colons
- client_address, client_port = client_info.rsplit(":", 1)
- client_type = "tcp"
- return {
- "time": float(command_time),
- "db": int(db_id),
- "client_address": client_address,
- "client_port": client_port,
- "client_type": client_type,
- "command": command,
- }
- def listen(self):
- """Listen for commands coming to the server."""
- while True:
- yield self.next_command()
- class PubSub:
- """
- PubSub provides publish, subscribe and listen support to Redis channels.
- After subscribing to one or more channels, the listen() method will block
- until a message arrives on one of the subscribed channels. That message
- will be returned and it's safe to start listening again.
- """
- PUBLISH_MESSAGE_TYPES = ("message", "pmessage", "smessage")
- UNSUBSCRIBE_MESSAGE_TYPES = ("unsubscribe", "punsubscribe", "sunsubscribe")
- HEALTH_CHECK_MESSAGE = "redis-py-health-check"
- def __init__(
- self,
- connection_pool,
- shard_hint=None,
- ignore_subscribe_messages: bool = False,
- encoder: Optional["Encoder"] = None,
- push_handler_func: Union[None, Callable[[str], None]] = None,
- ):
- self.connection_pool = connection_pool
- self.shard_hint = shard_hint
- self.ignore_subscribe_messages = ignore_subscribe_messages
- self.connection = None
- self.subscribed_event = threading.Event()
- # we need to know the encoding options for this connection in order
- # to lookup channel and pattern names for callback handlers.
- self.encoder = encoder
- self.push_handler_func = push_handler_func
- if self.encoder is None:
- self.encoder = self.connection_pool.get_encoder()
- self.health_check_response_b = self.encoder.encode(self.HEALTH_CHECK_MESSAGE)
- if self.encoder.decode_responses:
- self.health_check_response = ["pong", self.HEALTH_CHECK_MESSAGE]
- else:
- self.health_check_response = [b"pong", self.health_check_response_b]
- if self.push_handler_func is None:
- _set_info_logger()
- self.reset()
- def __enter__(self) -> "PubSub":
- return self
- def __exit__(self, exc_type, exc_value, traceback) -> None:
- self.reset()
- def __del__(self) -> None:
- try:
- # if this object went out of scope prior to shutting down
- # subscriptions, close the connection manually before
- # returning it to the connection pool
- self.reset()
- except Exception:
- pass
- def reset(self) -> None:
- if self.connection:
- self.connection.disconnect()
- self.connection.deregister_connect_callback(self.on_connect)
- self.connection_pool.release(self.connection)
- self.connection = None
- self.health_check_response_counter = 0
- self.channels = {}
- self.pending_unsubscribe_channels = set()
- self.shard_channels = {}
- self.pending_unsubscribe_shard_channels = set()
- self.patterns = {}
- self.pending_unsubscribe_patterns = set()
- self.subscribed_event.clear()
- def close(self) -> None:
- self.reset()
- def on_connect(self, connection) -> None:
- "Re-subscribe to any channels and patterns previously subscribed to"
- # NOTE: for python3, we can't pass bytestrings as keyword arguments
- # so we need to decode channel/pattern names back to unicode strings
- # before passing them to [p]subscribe.
- self.pending_unsubscribe_channels.clear()
- self.pending_unsubscribe_patterns.clear()
- self.pending_unsubscribe_shard_channels.clear()
- if self.channels:
- channels = {
- self.encoder.decode(k, force=True): v for k, v in self.channels.items()
- }
- self.subscribe(**channels)
- if self.patterns:
- patterns = {
- self.encoder.decode(k, force=True): v for k, v in self.patterns.items()
- }
- self.psubscribe(**patterns)
- if self.shard_channels:
- shard_channels = {
- self.encoder.decode(k, force=True): v
- for k, v in self.shard_channels.items()
- }
- self.ssubscribe(**shard_channels)
- @property
- def subscribed(self) -> bool:
- """Indicates if there are subscriptions to any channels or patterns"""
- return self.subscribed_event.is_set()
- def execute_command(self, *args):
- """Execute a publish/subscribe command"""
- # NOTE: don't parse the response in this function -- it could pull a
- # legitimate message off the stack if the connection is already
- # subscribed to one or more channels
- if self.connection is None:
- self.connection = self.connection_pool.get_connection(
- "pubsub", self.shard_hint
- )
- # register a callback that re-subscribes to any channels we
- # were listening to when we were disconnected
- self.connection.register_connect_callback(self.on_connect)
- if self.push_handler_func is not None and not HIREDIS_AVAILABLE:
- self.connection._parser.set_push_handler(self.push_handler_func)
- connection = self.connection
- kwargs = {"check_health": not self.subscribed}
- if not self.subscribed:
- self.clean_health_check_responses()
- self._execute(connection, connection.send_command, *args, **kwargs)
- def clean_health_check_responses(self) -> None:
- """
- If any health check responses are present, clean them
- """
- ttl = 10
- conn = self.connection
- while self.health_check_response_counter > 0 and ttl > 0:
- if self._execute(conn, conn.can_read, timeout=conn.socket_timeout):
- response = self._execute(conn, conn.read_response)
- if self.is_health_check_response(response):
- self.health_check_response_counter -= 1
- else:
- raise PubSubError(
- "A non health check response was cleaned by "
- "execute_command: {0}".format(response)
- )
- ttl -= 1
- def _disconnect_raise_connect(self, conn, error) -> None:
- """
- Close the connection and raise an exception
- if retry_on_error is not set or the error is not one
- of the specified error types. Otherwise, try to
- reconnect
- """
- conn.disconnect()
- if (
- conn.retry_on_error is None
- or isinstance(error, tuple(conn.retry_on_error)) is False
- ):
- raise error
- conn.connect()
- def _execute(self, conn, command, *args, **kwargs):
- """
- Connect manually upon disconnection. If the Redis server is down,
- this will fail and raise a ConnectionError as desired.
- After reconnection, the ``on_connect`` callback should have been
- called by the # connection to resubscribe us to any channels and
- patterns we were previously listening to
- """
- return conn.retry.call_with_retry(
- lambda: command(*args, **kwargs),
- lambda error: self._disconnect_raise_connect(conn, error),
- )
- def parse_response(self, block=True, timeout=0):
- """Parse the response from a publish/subscribe command"""
- conn = self.connection
- if conn is None:
- raise RuntimeError(
- "pubsub connection not set: "
- "did you forget to call subscribe() or psubscribe()?"
- )
- self.check_health()
- def try_read():
- if not block:
- if not conn.can_read(timeout=timeout):
- return None
- else:
- conn.connect()
- return conn.read_response(disconnect_on_error=False, push_request=True)
- response = self._execute(conn, try_read)
- if self.is_health_check_response(response):
- # ignore the health check message as user might not expect it
- self.health_check_response_counter -= 1
- return None
- return response
- def is_health_check_response(self, response) -> bool:
- """
- Check if the response is a health check response.
- If there are no subscriptions redis responds to PING command with a
- bulk response, instead of a multi-bulk with "pong" and the response.
- """
- return response in [
- self.health_check_response, # If there was a subscription
- self.health_check_response_b, # If there wasn't
- ]
- def check_health(self) -> None:
- conn = self.connection
- if conn is None:
- raise RuntimeError(
- "pubsub connection not set: "
- "did you forget to call subscribe() or psubscribe()?"
- )
- if conn.health_check_interval and time.time() > conn.next_health_check:
- conn.send_command("PING", self.HEALTH_CHECK_MESSAGE, check_health=False)
- self.health_check_response_counter += 1
- def _normalize_keys(self, data) -> Dict:
- """
- normalize channel/pattern names to be either bytes or strings
- based on whether responses are automatically decoded. this saves us
- from coercing the value for each message coming in.
- """
- encode = self.encoder.encode
- decode = self.encoder.decode
- return {decode(encode(k)): v for k, v in data.items()}
- def psubscribe(self, *args, **kwargs):
- """
- Subscribe to channel patterns. Patterns supplied as keyword arguments
- expect a pattern name as the key and a callable as the value. A
- pattern's callable will be invoked automatically when a message is
- received on that pattern rather than producing a message via
- ``listen()``.
- """
- if args:
- args = list_or_args(args[0], args[1:])
- new_patterns = dict.fromkeys(args)
- new_patterns.update(kwargs)
- ret_val = self.execute_command("PSUBSCRIBE", *new_patterns.keys())
- # update the patterns dict AFTER we send the command. we don't want to
- # subscribe twice to these patterns, once for the command and again
- # for the reconnection.
- new_patterns = self._normalize_keys(new_patterns)
- self.patterns.update(new_patterns)
- if not self.subscribed:
- # Set the subscribed_event flag to True
- self.subscribed_event.set()
- # Clear the health check counter
- self.health_check_response_counter = 0
- self.pending_unsubscribe_patterns.difference_update(new_patterns)
- return ret_val
- def punsubscribe(self, *args):
- """
- Unsubscribe from the supplied patterns. If empty, unsubscribe from
- all patterns.
- """
- if args:
- args = list_or_args(args[0], args[1:])
- patterns = self._normalize_keys(dict.fromkeys(args))
- else:
- patterns = self.patterns
- self.pending_unsubscribe_patterns.update(patterns)
- return self.execute_command("PUNSUBSCRIBE", *args)
- def subscribe(self, *args, **kwargs):
- """
- Subscribe to channels. Channels supplied as keyword arguments expect
- a channel name as the key and a callable as the value. A channel's
- callable will be invoked automatically when a message is received on
- that channel rather than producing a message via ``listen()`` or
- ``get_message()``.
- """
- if args:
- args = list_or_args(args[0], args[1:])
- new_channels = dict.fromkeys(args)
- new_channels.update(kwargs)
- ret_val = self.execute_command("SUBSCRIBE", *new_channels.keys())
- # update the channels dict AFTER we send the command. we don't want to
- # subscribe twice to these channels, once for the command and again
- # for the reconnection.
- new_channels = self._normalize_keys(new_channels)
- self.channels.update(new_channels)
- if not self.subscribed:
- # Set the subscribed_event flag to True
- self.subscribed_event.set()
- # Clear the health check counter
- self.health_check_response_counter = 0
- self.pending_unsubscribe_channels.difference_update(new_channels)
- return ret_val
- def unsubscribe(self, *args):
- """
- Unsubscribe from the supplied channels. If empty, unsubscribe from
- all channels
- """
- if args:
- args = list_or_args(args[0], args[1:])
- channels = self._normalize_keys(dict.fromkeys(args))
- else:
- channels = self.channels
- self.pending_unsubscribe_channels.update(channels)
- return self.execute_command("UNSUBSCRIBE", *args)
- def ssubscribe(self, *args, target_node=None, **kwargs):
- """
- Subscribes the client to the specified shard channels.
- Channels supplied as keyword arguments expect a channel name as the key
- and a callable as the value. A channel's callable will be invoked automatically
- when a message is received on that channel rather than producing a message via
- ``listen()`` or ``get_sharded_message()``.
- """
- if args:
- args = list_or_args(args[0], args[1:])
- new_s_channels = dict.fromkeys(args)
- new_s_channels.update(kwargs)
- ret_val = self.execute_command("SSUBSCRIBE", *new_s_channels.keys())
- # update the s_channels dict AFTER we send the command. we don't want to
- # subscribe twice to these channels, once for the command and again
- # for the reconnection.
- new_s_channels = self._normalize_keys(new_s_channels)
- self.shard_channels.update(new_s_channels)
- if not self.subscribed:
- # Set the subscribed_event flag to True
- self.subscribed_event.set()
- # Clear the health check counter
- self.health_check_response_counter = 0
- self.pending_unsubscribe_shard_channels.difference_update(new_s_channels)
- return ret_val
- def sunsubscribe(self, *args, target_node=None):
- """
- Unsubscribe from the supplied shard_channels. If empty, unsubscribe from
- all shard_channels
- """
- if args:
- args = list_or_args(args[0], args[1:])
- s_channels = self._normalize_keys(dict.fromkeys(args))
- else:
- s_channels = self.shard_channels
- self.pending_unsubscribe_shard_channels.update(s_channels)
- return self.execute_command("SUNSUBSCRIBE", *args)
- def listen(self):
- "Listen for messages on channels this client has been subscribed to"
- while self.subscribed:
- response = self.handle_message(self.parse_response(block=True))
- if response is not None:
- yield response
- def get_message(
- self, ignore_subscribe_messages: bool = False, timeout: float = 0.0
- ):
- """
- Get the next message if one is available, otherwise None.
- If timeout is specified, the system will wait for `timeout` seconds
- before returning. Timeout should be specified as a floating point
- number, or None, to wait indefinitely.
- """
- if not self.subscribed:
- # Wait for subscription
- start_time = time.time()
- if self.subscribed_event.wait(timeout) is True:
- # The connection was subscribed during the timeout time frame.
- # The timeout should be adjusted based on the time spent
- # waiting for the subscription
- time_spent = time.time() - start_time
- timeout = max(0.0, timeout - time_spent)
- else:
- # The connection isn't subscribed to any channels or patterns,
- # so no messages are available
- return None
- response = self.parse_response(block=(timeout is None), timeout=timeout)
- if response:
- return self.handle_message(response, ignore_subscribe_messages)
- return None
- get_sharded_message = get_message
- def ping(self, message: Union[str, None] = None) -> bool:
- """
- Ping the Redis server
- """
- args = ["PING", message] if message is not None else ["PING"]
- return self.execute_command(*args)
- def handle_message(self, response, ignore_subscribe_messages=False):
- """
- Parses a pub/sub message. If the channel or pattern was subscribed to
- with a message handler, the handler is invoked instead of a parsed
- message being returned.
- """
- if response is None:
- return None
- if isinstance(response, bytes):
- response = [b"pong", response] if response != b"PONG" else [b"pong", b""]
- message_type = str_if_bytes(response[0])
- if message_type == "pmessage":
- message = {
- "type": message_type,
- "pattern": response[1],
- "channel": response[2],
- "data": response[3],
- }
- elif message_type == "pong":
- message = {
- "type": message_type,
- "pattern": None,
- "channel": None,
- "data": response[1],
- }
- else:
- message = {
- "type": message_type,
- "pattern": None,
- "channel": response[1],
- "data": response[2],
- }
- # if this is an unsubscribe message, remove it from memory
- if message_type in self.UNSUBSCRIBE_MESSAGE_TYPES:
- if message_type == "punsubscribe":
- pattern = response[1]
- if pattern in self.pending_unsubscribe_patterns:
- self.pending_unsubscribe_patterns.remove(pattern)
- self.patterns.pop(pattern, None)
- elif message_type == "sunsubscribe":
- s_channel = response[1]
- if s_channel in self.pending_unsubscribe_shard_channels:
- self.pending_unsubscribe_shard_channels.remove(s_channel)
- self.shard_channels.pop(s_channel, None)
- else:
- channel = response[1]
- if channel in self.pending_unsubscribe_channels:
- self.pending_unsubscribe_channels.remove(channel)
- self.channels.pop(channel, None)
- if not self.channels and not self.patterns and not self.shard_channels:
- # There are no subscriptions anymore, set subscribed_event flag
- # to false
- self.subscribed_event.clear()
- if message_type in self.PUBLISH_MESSAGE_TYPES:
- # if there's a message handler, invoke it
- if message_type == "pmessage":
- handler = self.patterns.get(message["pattern"], None)
- elif message_type == "smessage":
- handler = self.shard_channels.get(message["channel"], None)
- else:
- handler = self.channels.get(message["channel"], None)
- if handler:
- handler(message)
- return None
- elif message_type != "pong":
- # this is a subscribe/unsubscribe message. ignore if we don't
- # want them
- if ignore_subscribe_messages or self.ignore_subscribe_messages:
- return None
- return message
- def run_in_thread(
- self,
- sleep_time: float = 0.0,
- daemon: bool = False,
- exception_handler: Optional[Callable] = None,
- ) -> "PubSubWorkerThread":
- for channel, handler in self.channels.items():
- if handler is None:
- raise PubSubError(f"Channel: '{channel}' has no handler registered")
- for pattern, handler in self.patterns.items():
- if handler is None:
- raise PubSubError(f"Pattern: '{pattern}' has no handler registered")
- for s_channel, handler in self.shard_channels.items():
- if handler is None:
- raise PubSubError(
- f"Shard Channel: '{s_channel}' has no handler registered"
- )
- thread = PubSubWorkerThread(
- self, sleep_time, daemon=daemon, exception_handler=exception_handler
- )
- thread.start()
- return thread
- class PubSubWorkerThread(threading.Thread):
- def __init__(
- self,
- pubsub,
- sleep_time: float,
- daemon: bool = False,
- exception_handler: Union[
- Callable[[Exception, "PubSub", "PubSubWorkerThread"], None], None
- ] = None,
- ):
- super().__init__()
- self.daemon = daemon
- self.pubsub = pubsub
- self.sleep_time = sleep_time
- self.exception_handler = exception_handler
- self._running = threading.Event()
- def run(self) -> None:
- if self._running.is_set():
- return
- self._running.set()
- pubsub = self.pubsub
- sleep_time = self.sleep_time
- while self._running.is_set():
- try:
- pubsub.get_message(ignore_subscribe_messages=True, timeout=sleep_time)
- except BaseException as e:
- if self.exception_handler is None:
- raise
- self.exception_handler(e, pubsub, self)
- pubsub.close()
- def stop(self) -> None:
- # trip the flag so the run loop exits. the run loop will
- # close the pubsub connection, which disconnects the socket
- # and returns the connection to the pool.
- self._running.clear()
- class Pipeline(Redis):
- """
- Pipelines provide a way to transmit multiple commands to the Redis server
- in one transmission. This is convenient for batch processing, such as
- saving all the values in a list to Redis.
- All commands executed within a pipeline are wrapped with MULTI and EXEC
- calls. This guarantees all commands executed in the pipeline will be
- executed atomically.
- Any command raising an exception does *not* halt the execution of
- subsequent commands in the pipeline. Instead, the exception is caught
- and its instance is placed into the response list returned by execute().
- Code iterating over the response list should be able to deal with an
- instance of an exception as a potential value. In general, these will be
- ResponseError exceptions, such as those raised when issuing a command
- on a key of a different datatype.
- """
- UNWATCH_COMMANDS = {"DISCARD", "EXEC", "UNWATCH"}
- def __init__(self, connection_pool, response_callbacks, transaction, shard_hint):
- self.connection_pool = connection_pool
- self.connection = None
- self.response_callbacks = response_callbacks
- self.transaction = transaction
- self.shard_hint = shard_hint
- self.watching = False
- self.reset()
- def __enter__(self) -> "Pipeline":
- return self
- def __exit__(self, exc_type, exc_value, traceback):
- self.reset()
- def __del__(self):
- try:
- self.reset()
- except Exception:
- pass
- def __len__(self) -> int:
- return len(self.command_stack)
- def __bool__(self) -> bool:
- """Pipeline instances should always evaluate to True"""
- return True
- def reset(self) -> None:
- self.command_stack = []
- self.scripts = set()
- # make sure to reset the connection state in the event that we were
- # watching something
- if self.watching and self.connection:
- try:
- # call this manually since our unwatch or
- # immediate_execute_command methods can call reset()
- self.connection.send_command("UNWATCH")
- self.connection.read_response()
- except ConnectionError:
- # disconnect will also remove any previous WATCHes
- self.connection.disconnect()
- # clean up the other instance attributes
- self.watching = False
- self.explicit_transaction = False
- # we can safely return the connection to the pool here since we're
- # sure we're no longer WATCHing anything
- if self.connection:
- self.connection_pool.release(self.connection)
- self.connection = None
- def close(self) -> None:
- """Close the pipeline"""
- self.reset()
- def multi(self) -> None:
- """
- Start a transactional block of the pipeline after WATCH commands
- are issued. End the transactional block with `execute`.
- """
- if self.explicit_transaction:
- raise RedisError("Cannot issue nested calls to MULTI")
- if self.command_stack:
- raise RedisError(
- "Commands without an initial WATCH have already been issued"
- )
- self.explicit_transaction = True
- def execute_command(self, *args, **kwargs):
- if (self.watching or args[0] == "WATCH") and not self.explicit_transaction:
- return self.immediate_execute_command(*args, **kwargs)
- return self.pipeline_execute_command(*args, **kwargs)
- def _disconnect_reset_raise(self, conn, error) -> None:
- """
- Close the connection, reset watching state and
- raise an exception if we were watching,
- if retry_on_error is not set or the error is not one
- of the specified error types.
- """
- conn.disconnect()
- # if we were already watching a variable, the watch is no longer
- # valid since this connection has died. raise a WatchError, which
- # indicates the user should retry this transaction.
- if self.watching:
- self.reset()
- raise WatchError(
- "A ConnectionError occurred on while watching one or more keys"
- )
- # if retry_on_error is not set or the error is not one
- # of the specified error types, raise it
- if (
- conn.retry_on_error is None
- or isinstance(error, tuple(conn.retry_on_error)) is False
- ):
- self.reset()
- raise
- def immediate_execute_command(self, *args, **options):
- """
- Execute a command immediately, but don't auto-retry on a
- ConnectionError if we're already WATCHing a variable. Used when
- issuing WATCH or subsequent commands retrieving their values but before
- MULTI is called.
- """
- command_name = args[0]
- conn = self.connection
- # if this is the first call, we need a connection
- if not conn:
- conn = self.connection_pool.get_connection(command_name, self.shard_hint)
- self.connection = conn
- return conn.retry.call_with_retry(
- lambda: self._send_command_parse_response(
- conn, command_name, *args, **options
- ),
- lambda error: self._disconnect_reset_raise(conn, error),
- )
- def pipeline_execute_command(self, *args, **options) -> "Pipeline":
- """
- Stage a command to be executed when execute() is next called
- Returns the current Pipeline object back so commands can be
- chained together, such as:
- pipe = pipe.set('foo', 'bar').incr('baz').decr('bang')
- At some other point, you can then run: pipe.execute(),
- which will execute all commands queued in the pipe.
- """
- self.command_stack.append((args, options))
- return self
- def _execute_transaction(self, connection, commands, raise_on_error) -> List:
- cmds = chain([(("MULTI",), {})], commands, [(("EXEC",), {})])
- all_cmds = connection.pack_commands(
- [args for args, options in cmds if EMPTY_RESPONSE not in options]
- )
- connection.send_packed_command(all_cmds)
- errors = []
- # parse off the response for MULTI
- # NOTE: we need to handle ResponseErrors here and continue
- # so that we read all the additional command messages from
- # the socket
- try:
- self.parse_response(connection, "_")
- except ResponseError as e:
- errors.append((0, e))
- # and all the other commands
- for i, command in enumerate(commands):
- if EMPTY_RESPONSE in command[1]:
- errors.append((i, command[1][EMPTY_RESPONSE]))
- else:
- try:
- self.parse_response(connection, "_")
- except ResponseError as e:
- self.annotate_exception(e, i + 1, command[0])
- errors.append((i, e))
- # parse the EXEC.
- try:
- response = self.parse_response(connection, "_")
- except ExecAbortError:
- if errors:
- raise errors[0][1]
- raise
- # EXEC clears any watched keys
- self.watching = False
- if response is None:
- raise WatchError("Watched variable changed.")
- # put any parse errors into the response
- for i, e in errors:
- response.insert(i, e)
- if len(response) != len(commands):
- self.connection.disconnect()
- raise ResponseError(
- "Wrong number of response items from pipeline execution"
- )
- # find any errors in the response and raise if necessary
- if raise_on_error:
- self.raise_first_error(commands, response)
- # We have to run response callbacks manually
- data = []
- for r, cmd in zip(response, commands):
- if not isinstance(r, Exception):
- args, options = cmd
- command_name = args[0]
- if command_name in self.response_callbacks:
- r = self.response_callbacks[command_name](r, **options)
- data.append(r)
- return data
- def _execute_pipeline(self, connection, commands, raise_on_error):
- # build up all commands into a single request to increase network perf
- all_cmds = connection.pack_commands([args for args, _ in commands])
- connection.send_packed_command(all_cmds)
- response = []
- for args, options in commands:
- try:
- response.append(self.parse_response(connection, args[0], **options))
- except ResponseError as e:
- response.append(e)
- if raise_on_error:
- self.raise_first_error(commands, response)
- return response
- def raise_first_error(self, commands, response):
- for i, r in enumerate(response):
- if isinstance(r, ResponseError):
- self.annotate_exception(r, i + 1, commands[i][0])
- raise r
- def annotate_exception(self, exception, number, command):
- cmd = " ".join(map(safe_str, command))
- msg = (
- f"Command # {number} ({cmd}) of pipeline "
- f"caused error: {exception.args[0]}"
- )
- exception.args = (msg,) + exception.args[1:]
- def parse_response(self, connection, command_name, **options):
- result = Redis.parse_response(self, connection, command_name, **options)
- if command_name in self.UNWATCH_COMMANDS:
- self.watching = False
- elif command_name == "WATCH":
- self.watching = True
- return result
- def load_scripts(self):
- # make sure all scripts that are about to be run on this pipeline exist
- scripts = list(self.scripts)
- immediate = self.immediate_execute_command
- shas = [s.sha for s in scripts]
- # we can't use the normal script_* methods because they would just
- # get buffered in the pipeline.
- exists = immediate("SCRIPT EXISTS", *shas)
- if not all(exists):
- for s, exist in zip(scripts, exists):
- if not exist:
- s.sha = immediate("SCRIPT LOAD", s.script)
- def _disconnect_raise_reset(
- self,
- conn: AbstractConnection,
- error: Exception,
- ) -> None:
- """
- Close the connection, raise an exception if we were watching,
- and raise an exception if retry_on_error is not set or the
- error is not one of the specified error types.
- """
- conn.disconnect()
- # if we were watching a variable, the watch is no longer valid
- # since this connection has died. raise a WatchError, which
- # indicates the user should retry this transaction.
- if self.watching:
- raise WatchError(
- "A ConnectionError occurred on while watching one or more keys"
- )
- # if retry_on_error is not set or the error is not one
- # of the specified error types, raise it
- if (
- conn.retry_on_error is None
- or isinstance(error, tuple(conn.retry_on_error)) is False
- ):
- self.reset()
- raise error
- def execute(self, raise_on_error=True):
- """Execute all the commands in the current pipeline"""
- stack = self.command_stack
- if not stack and not self.watching:
- return []
- if self.scripts:
- self.load_scripts()
- if self.transaction or self.explicit_transaction:
- execute = self._execute_transaction
- else:
- execute = self._execute_pipeline
- conn = self.connection
- if not conn:
- conn = self.connection_pool.get_connection("MULTI", self.shard_hint)
- # assign to self.connection so reset() releases the connection
- # back to the pool after we're done
- self.connection = conn
- try:
- return conn.retry.call_with_retry(
- lambda: execute(conn, stack, raise_on_error),
- lambda error: self._disconnect_raise_reset(conn, error),
- )
- finally:
- self.reset()
- def discard(self):
- """
- Flushes all previously queued commands
- See: https://redis.io/commands/DISCARD
- """
- self.execute_command("DISCARD")
- def watch(self, *names):
- """Watches the values at keys ``names``"""
- if self.explicit_transaction:
- raise RedisError("Cannot issue a WATCH after a MULTI")
- return self.execute_command("WATCH", *names)
- def unwatch(self) -> bool:
- """Unwatches all previously specified keys"""
- return self.watching and self.execute_command("UNWATCH") or True
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