Source code for langchain_community.utilities.redis

from __future__ import annotations

import logging
import re
from typing import TYPE_CHECKING, Any, List, Optional, Pattern
from urllib.parse import urlparse

import numpy as np

logger = logging.getLogger(__name__)

if TYPE_CHECKING:
    from redis.client import Redis as RedisType


def _array_to_buffer(array: List[float], dtype: Any = np.float32) -> bytes:
    return np.array(array).astype(dtype).tobytes()


def _buffer_to_array(buffer: bytes, dtype: Any = np.float32) -> List[float]:
    return np.frombuffer(buffer, dtype=dtype).tolist()


[docs]class TokenEscaper: """ Escape punctuation within an input string. """ # Characters that RediSearch requires us to escape during queries. # Source: https://redis.io/docs/stack/search/reference/escaping/#the-rules-of-text-field-tokenization DEFAULT_ESCAPED_CHARS = r"[,.<>{}\[\]\\\"\':;!@#$%^&*()\-+=~\/ ]"
[docs] def __init__(self, escape_chars_re: Optional[Pattern] = None): if escape_chars_re: self.escaped_chars_re = escape_chars_re else: self.escaped_chars_re = re.compile(self.DEFAULT_ESCAPED_CHARS)
[docs] def escape(self, value: str) -> str: if not isinstance(value, str): raise TypeError( "Value must be a string object for token escaping." f"Got type {type(value)}" ) def escape_symbol(match: re.Match) -> str: value = match.group(0) return f"\\{value}" return self.escaped_chars_re.sub(escape_symbol, value)
[docs]def check_redis_module_exist(client: RedisType, required_modules: List[dict]) -> None: """Check if the correct Redis modules are installed.""" installed_modules = client.module_list() installed_modules = { module[b"name"].decode("utf-8"): module for module in installed_modules } for module in required_modules: if module["name"] in installed_modules and int( installed_modules[module["name"]][b"ver"] ) >= int(module["ver"]): return # otherwise raise error error_message = ( "Redis cannot be used as a vector database without RediSearch >=2.4" "Please head to https://redis.io/docs/stack/search/quick_start/" "to know more about installing the RediSearch module within Redis Stack." ) logger.error(error_message) raise ValueError(error_message)
[docs]def get_client(redis_url: str, **kwargs: Any) -> RedisType: """Get a redis client from the connection url given. This helper accepts urls for Redis server (TCP with/without TLS or UnixSocket) as well as Redis Sentinel connections. Redis Cluster is not supported. Before creating a connection the existence of the database driver is checked an and ValueError raised otherwise To use, you should have the ``redis`` python package installed. Example: .. code-block:: python from langchain_community.utilities.redis import get_client redis_client = get_client( redis_url="redis://username:password@localhost:6379" index_name="my-index", embedding_function=embeddings.embed_query, ) To use a redis replication setup with multiple redis server and redis sentinels set "redis_url" to "redis+sentinel://" scheme. With this url format a path is needed holding the name of the redis service within the sentinels to get the correct redis server connection. The default service name is "mymaster". The optional second part of the path is the redis db number to connect to. An optional username or password is used for booth connections to the rediserver and the sentinel, different passwords for server and sentinel are not supported. And as another constraint only one sentinel instance can be given: Example: .. code-block:: python from langchain_community.utilities.redis import get_client redis_client = get_client( redis_url="redis+sentinel://username:password@sentinelhost:26379/mymaster/0" index_name="my-index", embedding_function=embeddings.embed_query, ) """ # Initialize with necessary components. try: import redis except ImportError: raise ImportError( "Could not import redis python package. " "Please install it with `pip install redis>=4.1.0`." ) # check if normal redis:// or redis+sentinel:// url if redis_url.startswith("redis+sentinel"): redis_client = _redis_sentinel_client(redis_url, **kwargs) elif redis_url.startswith("rediss+sentinel"): # sentinel with TLS support enables kwargs["ssl"] = True if "ssl_cert_reqs" not in kwargs: kwargs["ssl_cert_reqs"] = "none" redis_client = _redis_sentinel_client(redis_url, **kwargs) else: # connect to redis server from url, reconnect with cluster client if needed redis_client = redis.from_url(redis_url, **kwargs) if _check_for_cluster(redis_client): redis_client.close() redis_client = _redis_cluster_client(redis_url, **kwargs) return redis_client
def _redis_sentinel_client(redis_url: str, **kwargs: Any) -> RedisType: """helper method to parse an (un-official) redis+sentinel url and create a Sentinel connection to fetch the final redis client connection to a replica-master for read-write operations. If username and/or password for authentication is given the same credentials are used for the Redis Sentinel as well as Redis Server. With this implementation using a redis url only it is not possible to use different data for authentication on booth systems. """ import redis parsed_url = urlparse(redis_url) # sentinel needs list with (host, port) tuple, use default port if none available sentinel_list = [(parsed_url.hostname or "localhost", parsed_url.port or 26379)] if parsed_url.path: # "/mymaster/0" first part is service name, optional second part is db number path_parts = parsed_url.path.split("/") service_name = path_parts[1] or "mymaster" if len(path_parts) > 2: kwargs["db"] = path_parts[2] else: service_name = "mymaster" sentinel_args = {} if parsed_url.password: sentinel_args["password"] = parsed_url.password kwargs["password"] = parsed_url.password if parsed_url.username: sentinel_args["username"] = parsed_url.username kwargs["username"] = parsed_url.username # check for all SSL related properties and copy them into sentinel_kwargs too, # add client_name also for arg in kwargs: if arg.startswith("ssl") or arg == "client_name": sentinel_args[arg] = kwargs[arg] # sentinel user/pass is part of sentinel_kwargs, user/pass for redis server # connection as direct parameter in kwargs sentinel_client = redis.sentinel.Sentinel( sentinel_list, sentinel_kwargs=sentinel_args, **kwargs ) # redis server might have password but not sentinel - fetch this error and try # again without pass, everything else cannot be handled here -> user needed try: sentinel_client.execute_command("ping") except redis.exceptions.AuthenticationError as ae: if "no password is set" in ae.args[0]: logger.warning( "Redis sentinel connection configured with password but Sentinel \ answered NO PASSWORD NEEDED - Please check Sentinel configuration" ) sentinel_client = redis.sentinel.Sentinel(sentinel_list, **kwargs) else: raise ae return sentinel_client.master_for(service_name) def _check_for_cluster(redis_client: RedisType) -> bool: import redis try: cluster_info = redis_client.info("cluster") return cluster_info["cluster_enabled"] == 1 except redis.exceptions.RedisError: return False def _redis_cluster_client(redis_url: str, **kwargs: Any) -> RedisType: from redis.cluster import RedisCluster return RedisCluster.from_url(redis_url, **kwargs) # type: ignore[return-value]