Source code for langchain_community.vectorstores.redis.base

"""Wrapper around Redis vector database."""

from __future__ import annotations

import logging
import os
import uuid
from typing import (
    TYPE_CHECKING,
    Any,
    Callable,
    Dict,
    Iterable,
    List,
    Mapping,
    Optional,
    Tuple,
    Type,
    Union,
    cast,
)

import numpy as np
import yaml
from langchain_core._api import deprecated
from langchain_core.callbacks import (
    AsyncCallbackManagerForRetrieverRun,
    CallbackManagerForRetrieverRun,
)
from langchain_core.documents import Document
from langchain_core.embeddings import Embeddings
from langchain_core.utils import get_from_dict_or_env
from langchain_core.vectorstores import VectorStore, VectorStoreRetriever

from langchain_community.utilities.redis import (
    _array_to_buffer,
    _buffer_to_array,
    check_redis_module_exist,
    get_client,
)
from langchain_community.vectorstores.redis.constants import (
    REDIS_REQUIRED_MODULES,
    REDIS_TAG_SEPARATOR,
)
from langchain_community.vectorstores.utils import maximal_marginal_relevance

logger = logging.getLogger(__name__)
ListOfDict = List[Dict[str, str]]

if TYPE_CHECKING:
    from redis.client import Redis as RedisType
    from redis.commands.search.query import Query

    from langchain_community.vectorstores.redis.filters import RedisFilterExpression
    from langchain_community.vectorstores.redis.schema import RedisModel


def _default_relevance_score(val: float) -> float:
    return 1 - val


[docs]def check_index_exists(client: RedisType, index_name: str) -> bool: """Check if Redis index exists.""" try: client.ft(index_name).info() except: # noqa: E722 logger.debug("Index does not exist") return False logger.debug("Index already exists") return True
[docs]class Redis(VectorStore): """Redis vector database. To use, you should have the ``redis`` python package installed and have a running Redis Enterprise or Redis-Stack server For production use cases, it is recommended to use Redis Enterprise as the scaling, performance, stability and availability is much better than Redis-Stack. For testing and prototyping, however, this is not required. Redis-Stack is available as a docker container the full vector search API available. .. code-block:: bash # to run redis stack in docker locally docker run -d -p 6379:6379 -p 8001:8001 redis/redis-stack:latest Once running, you can connect to the redis server with the following url schemas: - redis://<host>:<port> # simple connection - redis://<username>:<password>@<host>:<port> # connection with authentication - rediss://<host>:<port> # connection with SSL - rediss://<username>:<password>@<host>:<port> # connection with SSL and auth Examples: The following examples show various ways to use the Redis VectorStore with LangChain. For all the following examples assume we have the following imports: .. code-block:: python from langchain_community.vectorstores import Redis from langchain_community.embeddings import OpenAIEmbeddings Initialize, create index, and load Documents .. code-block:: python from langchain_community.vectorstores import Redis from langchain_community.embeddings import OpenAIEmbeddings rds = Redis.from_documents( documents, # a list of Document objects from loaders or created embeddings, # an Embeddings object redis_url="redis://localhost:6379", ) Initialize, create index, and load Documents with metadata .. code-block:: python rds = Redis.from_texts( texts, # a list of strings metadata, # a list of metadata dicts embeddings, # an Embeddings object redis_url="redis://localhost:6379", ) Initialize, create index, and load Documents with metadata and return keys .. code-block:: python rds, keys = Redis.from_texts_return_keys( texts, # a list of strings metadata, # a list of metadata dicts embeddings, # an Embeddings object redis_url="redis://localhost:6379", ) For use cases where the index needs to stay alive, you can initialize with an index name such that it's easier to reference later .. code-block:: python rds = Redis.from_texts( texts, # a list of strings metadata, # a list of metadata dicts embeddings, # an Embeddings object index_name="my-index", redis_url="redis://localhost:6379", ) Initialize and connect to an existing index (from above) .. code-block:: python # must pass in schema and key_prefix from another index existing_rds = Redis.from_existing_index( embeddings, # an Embeddings object index_name="my-index", schema=rds.schema, # schema dumped from another index key_prefix=rds.key_prefix, # key prefix from another index redis_url="redis://localhost:6379", ) Advanced examples: Custom vector schema can be supplied to change the way that Redis creates the underlying vector schema. This is useful for production use cases where you want to optimize the vector schema for your use case. ex. using HNSW instead of FLAT (knn) which is the default .. code-block:: python vector_schema = { "algorithm": "HNSW" } rds = Redis.from_texts( texts, # a list of strings metadata, # a list of metadata dicts embeddings, # an Embeddings object vector_schema=vector_schema, redis_url="redis://localhost:6379", ) Custom index schema can be supplied to change the way that the metadata is indexed. This is useful for you would like to use the hybrid querying (filtering) capability of Redis. By default, this implementation will automatically generate the index schema according to the following rules: - All strings are indexed as text fields - All numbers are indexed as numeric fields - All lists of strings are indexed as tag fields (joined by langchain_community.vectorstores.redis.constants.REDIS_TAG_SEPARATOR) - All None values are not indexed but still stored in Redis these are not retrievable through the interface here, but the raw Redis client can be used to retrieve them. - All other types are not indexed To override these rules, you can pass in a custom index schema like the following .. code-block:: yaml tag: - name: credit_score text: - name: user - name: job Typically, the ``credit_score`` field would be a text field since it's a string, however, we can override this behavior by specifying the field type as shown with the yaml config (can also be a dictionary) above and the code below. .. code-block:: python rds = Redis.from_texts( texts, # a list of strings metadata, # a list of metadata dicts embeddings, # an Embeddings object index_schema="path/to/index_schema.yaml", # can also be a dictionary redis_url="redis://localhost:6379", ) When connecting to an existing index where a custom schema has been applied, it's important to pass in the same schema to the ``from_existing_index`` method. Otherwise, the schema for newly added samples will be incorrect and metadata will not be returned. """ DEFAULT_VECTOR_SCHEMA = { "name": "content_vector", "algorithm": "FLAT", "dims": 1536, "distance_metric": "COSINE", "datatype": "FLOAT32", }
[docs] def __init__( self, redis_url: str, index_name: str, embedding: Embeddings, index_schema: Optional[Union[Dict[str, ListOfDict], str, os.PathLike]] = None, vector_schema: Optional[Dict[str, Union[str, int]]] = None, relevance_score_fn: Optional[Callable[[float], float]] = None, key_prefix: Optional[str] = None, **kwargs: Any, ): """Initialize Redis vector store with necessary components.""" self._check_deprecated_kwargs(kwargs) try: # TODO use importlib to check if redis is installed import redis # noqa: F401 except ImportError as e: raise ImportError( "Could not import redis python package. " "Please install it with `pip install redis`." ) from e self.index_name = index_name self._embeddings = embedding try: redis_client = get_client(redis_url=redis_url, **kwargs) # check if redis has redisearch module installed check_redis_module_exist(redis_client, REDIS_REQUIRED_MODULES) except ValueError as e: raise ValueError(f"Redis failed to connect: {e}") self.client = redis_client self.relevance_score_fn = relevance_score_fn self._schema = self._get_schema_with_defaults(index_schema, vector_schema) self.key_prefix = key_prefix if key_prefix is not None else f"doc:{index_name}"
@property def embeddings(self) -> Optional[Embeddings]: """Access the query embedding object if available.""" return self._embeddings
[docs] @classmethod def from_texts_return_keys( cls, texts: List[str], embedding: Embeddings, metadatas: Optional[List[dict]] = None, index_name: Optional[str] = None, index_schema: Optional[Union[Dict[str, ListOfDict], str, os.PathLike]] = None, vector_schema: Optional[Dict[str, Union[str, int]]] = None, **kwargs: Any, ) -> Tuple[Redis, List[str]]: """Create a Redis vectorstore from raw documents. This is a user-friendly interface that: 1. Embeds documents. 2. Creates a new Redis index if it doesn't already exist 3. Adds the documents to the newly created Redis index. 4. Returns the keys of the newly created documents once stored. This method will generate schema based on the metadata passed in if the `index_schema` is not defined. If the `index_schema` is defined, it will compare against the generated schema and warn if there are differences. If you are purposefully defining the schema for the metadata, then you can ignore that warning. To examine the schema options, initialize an instance of this class and print out the schema using the `Redis.schema`` property. This will include the content and content_vector classes which are always present in the langchain schema. Example: .. code-block:: python from langchain_community.vectorstores import Redis from langchain_community.embeddings import OpenAIEmbeddings embeddings = OpenAIEmbeddings() redis, keys = Redis.from_texts_return_keys( texts, embeddings, redis_url="redis://localhost:6379" ) Args: texts (List[str]): List of texts to add to the vectorstore. embedding (Embeddings): Embeddings to use for the vectorstore. metadatas (Optional[List[dict]], optional): Optional list of metadata dicts to add to the vectorstore. Defaults to None. index_name (Optional[str], optional): Optional name of the index to create or add to. Defaults to None. index_schema (Optional[Union[Dict[str, ListOfDict], str, os.PathLike]], optional): Optional fields to index within the metadata. Overrides generated schema. Defaults to None. vector_schema (Optional[Dict[str, Union[str, int]]], optional): Optional vector schema to use. Defaults to None. **kwargs (Any): Additional keyword arguments to pass to the Redis client. Returns: Tuple[Redis, List[str]]: Tuple of the Redis instance and the keys of the newly created documents. Raises: ValueError: If the number of metadatas does not match the number of texts. """ try: # TODO use importlib to check if redis is installed import redis # noqa: F401 from langchain_community.vectorstores.redis.schema import read_schema except ImportError as e: raise ImportError( "Could not import redis python package. " "Please install it with `pip install redis`." ) from e redis_url = get_from_dict_or_env(kwargs, "redis_url", "REDIS_URL") if "redis_url" in kwargs: kwargs.pop("redis_url") # flag to use generated schema if "generate" in kwargs: kwargs.pop("generate") # see if the user specified keys keys = None if "keys" in kwargs: keys = kwargs.pop("keys") # Name of the search index if not given if not index_name: index_name = uuid.uuid4().hex # type check for metadata if metadatas: if isinstance(metadatas, list) and len(metadatas) != len(texts): # type: ignore raise ValueError("Number of metadatas must match number of texts") if not (isinstance(metadatas, list) and isinstance(metadatas[0], dict)): raise ValueError("Metadatas must be a list of dicts") generated_schema = _generate_field_schema(metadatas[0]) if index_schema: # read in the schema solely to compare to the generated schema user_schema = read_schema(index_schema) # type: ignore # the very rare case where a super user decides to pass the index # schema and a document loader is used that has metadata which # we need to map into fields. if user_schema != generated_schema: logger.warning( "`index_schema` does not match generated metadata schema.\n" + "If you meant to manually override the schema, please " + "ignore this message.\n" + f"index_schema: {user_schema}\n" + f"generated_schema: {generated_schema}\n" ) else: # use the generated schema index_schema = generated_schema # Create instance # init the class -- if Redis is unavailable, will throw exception instance = cls( redis_url, index_name, embedding, index_schema=index_schema, vector_schema=vector_schema, **kwargs, ) # Add data to Redis keys = instance.add_texts(texts, metadatas, keys=keys) return instance, keys
[docs] @classmethod def from_texts( cls: Type[Redis], texts: List[str], embedding: Embeddings, metadatas: Optional[List[dict]] = None, index_name: Optional[str] = None, index_schema: Optional[Union[Dict[str, ListOfDict], str, os.PathLike]] = None, vector_schema: Optional[Dict[str, Union[str, int]]] = None, **kwargs: Any, ) -> Redis: """Create a Redis vectorstore from a list of texts. This is a user-friendly interface that: 1. Embeds documents. 2. Creates a new Redis index if it doesn't already exist 3. Adds the documents to the newly created Redis index. This method will generate schema based on the metadata passed in if the `index_schema` is not defined. If the `index_schema` is defined, it will compare against the generated schema and warn if there are differences. If you are purposefully defining the schema for the metadata, then you can ignore that warning. To examine the schema options, initialize an instance of this class and print out the schema using the `Redis.schema`` property. This will include the content and content_vector classes which are always present in the langchain schema. Example: .. code-block:: python from langchain_community.vectorstores import Redis from langchain_community.embeddings import OpenAIEmbeddings embeddings = OpenAIEmbeddings() redisearch = RediSearch.from_texts( texts, embeddings, redis_url="redis://username:password@localhost:6379" ) Args: texts (List[str]): List of texts to add to the vectorstore. embedding (Embeddings): Embedding model class (i.e. OpenAIEmbeddings) for embedding queries. metadatas (Optional[List[dict]], optional): Optional list of metadata dicts to add to the vectorstore. Defaults to None. index_name (Optional[str], optional): Optional name of the index to create or add to. Defaults to None. index_schema (Optional[Union[Dict[str, ListOfDict], str, os.PathLike]], optional): Optional fields to index within the metadata. Overrides generated schema. Defaults to None. vector_schema (Optional[Dict[str, Union[str, int]]], optional): Optional vector schema to use. Defaults to None. **kwargs (Any): Additional keyword arguments to pass to the Redis client. Returns: Redis: Redis VectorStore instance. Raises: ValueError: If the number of metadatas does not match the number of texts. ImportError: If the redis python package is not installed. """ instance, _ = cls.from_texts_return_keys( texts, embedding, metadatas=metadatas, index_name=index_name, index_schema=index_schema, vector_schema=vector_schema, **kwargs, ) return instance
[docs] @classmethod def from_existing_index( cls, embedding: Embeddings, index_name: str, schema: Union[Dict[str, ListOfDict], str, os.PathLike, Dict[str, ListOfDict]], key_prefix: Optional[str] = None, **kwargs: Any, ) -> Redis: """Connect to an existing Redis index. Example: .. code-block:: python from langchain_community.vectorstores import Redis from langchain_community.embeddings import OpenAIEmbeddings embeddings = OpenAIEmbeddings() # must pass in schema and key_prefix from another index existing_rds = Redis.from_existing_index( embeddings, index_name="my-index", schema=rds.schema, # schema dumped from another index key_prefix=rds.key_prefix, # key prefix from another index redis_url="redis://username:password@localhost:6379", ) Args: embedding (Embeddings): Embedding model class (i.e. OpenAIEmbeddings) for embedding queries. index_name (str): Name of the index to connect to. schema (Union[Dict[str, str], str, os.PathLike, Dict[str, ListOfDict]]): Schema of the index and the vector schema. Can be a dict, or path to yaml file. key_prefix (Optional[str]): Prefix to use for all keys in Redis associated with this index. **kwargs (Any): Additional keyword arguments to pass to the Redis client. Returns: Redis: Redis VectorStore instance. Raises: ValueError: If the index does not exist. ImportError: If the redis python package is not installed. """ redis_url = get_from_dict_or_env(kwargs, "redis_url", "REDIS_URL") # We need to first remove redis_url from kwargs, # otherwise passing it to Redis will result in an error. if "redis_url" in kwargs: kwargs.pop("redis_url") # Create instance # init the class -- if Redis is unavailable, will throw exception instance = cls( redis_url, index_name, embedding, index_schema=schema, key_prefix=key_prefix, **kwargs, ) # Check for existence of the declared index if not check_index_exists(instance.client, index_name): # Will only raise if the running Redis server does not # have a record of this particular index raise ValueError( f"Redis failed to connect: Index {index_name} does not exist." ) return instance
@property def schema(self) -> Dict[str, List[Any]]: """Return the schema of the index.""" return self._schema.as_dict()
[docs] def write_schema(self, path: Union[str, os.PathLike]) -> None: """Write the schema to a yaml file.""" with open(path, "w+") as f: yaml.dump(self.schema, f)
[docs] @staticmethod def delete( ids: Optional[List[str]] = None, **kwargs: Any, ) -> bool: """ Delete a Redis entry. Args: ids: List of ids (keys in redis) to delete. redis_url: Redis connection url. This should be passed in the kwargs or set as an environment variable: REDIS_URL. Returns: bool: Whether or not the deletions were successful. Raises: ValueError: If the redis python package is not installed. ValueError: If the ids (keys in redis) are not provided """ redis_url = get_from_dict_or_env(kwargs, "redis_url", "REDIS_URL") if ids is None: raise ValueError("'ids' (keys)() were not provided.") try: import redis # noqa: F401 except ImportError: raise ImportError( "Could not import redis python package. " "Please install it with `pip install redis`." ) try: # We need to first remove redis_url from kwargs, # otherwise passing it to Redis will result in an error. if "redis_url" in kwargs: kwargs.pop("redis_url") client = get_client(redis_url=redis_url, **kwargs) except ValueError as e: raise ValueError(f"Your redis connected error: {e}") # Check if index exists try: client.delete(*ids) logger.info("Entries deleted") return True except: # noqa: E722 # ids does not exist return False
[docs] @staticmethod def drop_index( index_name: str, delete_documents: bool, **kwargs: Any, ) -> bool: """ Drop a Redis search index. Args: index_name (str): Name of the index to drop. delete_documents (bool): Whether to drop the associated documents. Returns: bool: Whether or not the drop was successful. """ redis_url = get_from_dict_or_env(kwargs, "redis_url", "REDIS_URL") try: import redis # noqa: F401 except ImportError: raise ImportError( "Could not import redis python package. " "Please install it with `pip install redis`." ) try: # We need to first remove redis_url from kwargs, # otherwise passing it to Redis will result in an error. if "redis_url" in kwargs: kwargs.pop("redis_url") client = get_client(redis_url=redis_url, **kwargs) except ValueError as e: raise ValueError(f"Your redis connected error: {e}") # Check if index exists try: client.ft(index_name).dropindex(delete_documents) logger.info("Drop index") return True except: # noqa: E722 # Index not exist return False
[docs] def add_texts( self, texts: Iterable[str], metadatas: Optional[List[dict]] = None, embeddings: Optional[List[List[float]]] = None, batch_size: int = 1000, clean_metadata: bool = True, **kwargs: Any, ) -> List[str]: """Add more texts to the vectorstore. Args: texts (Iterable[str]): Iterable of strings/text to add to the vectorstore. metadatas (Optional[List[dict]], optional): Optional list of metadatas. Defaults to None. embeddings (Optional[List[List[float]]], optional): Optional pre-generated embeddings. Defaults to None. keys (List[str]) or ids (List[str]): Identifiers of entries. Defaults to None. batch_size (int, optional): Batch size to use for writes. Defaults to 1000. Returns: List[str]: List of ids added to the vectorstore """ ids = [] # Get keys or ids from kwargs # Other vectorstores use ids keys_or_ids = kwargs.get("keys", kwargs.get("ids")) # type check for metadata if metadatas: if isinstance(metadatas, list) and len(metadatas) != len(texts): # type: ignore raise ValueError("Number of metadatas must match number of texts") if not (isinstance(metadatas, list) and isinstance(metadatas[0], dict)): raise ValueError("Metadatas must be a list of dicts") embeddings = embeddings or self._embeddings.embed_documents(list(texts)) self._create_index_if_not_exist(dim=len(embeddings[0])) # Write data to redis pipeline = self.client.pipeline(transaction=False) for i, text in enumerate(texts): # Use provided values by default or fallback key = keys_or_ids[i] if keys_or_ids else str(uuid.uuid4().hex) if not key.startswith(self.key_prefix + ":"): key = self.key_prefix + ":" + key metadata = metadatas[i] if metadatas else {} metadata = _prepare_metadata(metadata) if clean_metadata else metadata pipeline.hset( key, mapping={ self._schema.content_key: text, self._schema.content_vector_key: _array_to_buffer( embeddings[i], self._schema.vector_dtype ), **metadata, }, ) ids.append(key) # Write batch if i % batch_size == 0: pipeline.execute() # Cleanup final batch pipeline.execute() return ids
[docs] def as_retriever(self, **kwargs: Any) -> RedisVectorStoreRetriever: tags = kwargs.pop("tags", None) or [] tags.extend(self._get_retriever_tags()) return RedisVectorStoreRetriever(vectorstore=self, **kwargs, tags=tags)
[docs] @deprecated("0.0.1", alternative="similarity_search(distance_threshold=0.1)") def similarity_search_limit_score( self, query: str, k: int = 4, score_threshold: float = 0.2, **kwargs: Any ) -> List[Document]: """ Returns the most similar indexed documents to the query text within the score_threshold range. Deprecated: Use similarity_search with distance_threshold instead. Args: query (str): The query text for which to find similar documents. k (int): The number of documents to return. Default is 4. score_threshold (float): The minimum matching *distance* required for a document to be considered a match. Defaults to 0.2. Returns: List[Document]: A list of documents that are most similar to the query text including the match score for each document. Note: If there are no documents that satisfy the score_threshold value, an empty list is returned. """ return self.similarity_search( query, k=k, distance_threshold=score_threshold, **kwargs )
[docs] def similarity_search_with_score( self, query: str, k: int = 4, filter: Optional[RedisFilterExpression] = None, return_metadata: bool = True, **kwargs: Any, ) -> List[Tuple[Document, float]]: """Run similarity search with **vector distance**. The "scores" returned from this function are the raw vector distances from the query vector. For similarity scores, use ``similarity_search_with_relevance_scores``. Args: query (str): The query text for which to find similar documents. k (int): The number of documents to return. Default is 4. filter (RedisFilterExpression, optional): Optional metadata filter. Defaults to None. return_metadata (bool, optional): Whether to return metadata. Defaults to True. Returns: List[Tuple[Document, float]]: A list of documents that are most similar to the query with the distance for each document. """ try: import redis except ImportError as e: raise ImportError( "Could not import redis python package. " "Please install it with `pip install redis`." ) from e if "score_threshold" in kwargs: logger.warning( "score_threshold is deprecated. Use distance_threshold instead." + "score_threshold should only be used in " + "similarity_search_with_relevance_scores." + "score_threshold will be removed in a future release.", ) query_embedding = self._embeddings.embed_query(query) redis_query, params_dict = self._prepare_query( query_embedding, k=k, filter=filter, with_metadata=return_metadata, with_distance=True, **kwargs, ) # Perform vector search # ignore type because redis-py is wrong about bytes try: results = self.client.ft(self.index_name).search(redis_query, params_dict) # type: ignore except redis.exceptions.ResponseError as e: # split error message and see if it starts with "Syntax" if str(e).split(" ")[0] == "Syntax": raise ValueError( "Query failed with syntax error. " + "This is likely due to malformation of " + "filter, vector, or query argument" ) from e raise e # Prepare document results docs_with_scores: List[Tuple[Document, float]] = [] for result in results.docs: metadata = {} if return_metadata: metadata = {"id": result.id} metadata.update(self._collect_metadata(result)) doc = Document(page_content=result.content, metadata=metadata) distance = self._calculate_fp_distance(result.distance) docs_with_scores.append((doc, distance)) return docs_with_scores
[docs] def similarity_search_by_vector( self, embedding: List[float], k: int = 4, filter: Optional[RedisFilterExpression] = None, return_metadata: bool = True, distance_threshold: Optional[float] = None, **kwargs: Any, ) -> List[Document]: """Run similarity search between a query vector and the indexed vectors. Args: embedding (List[float]): The query vector for which to find similar documents. k (int): The number of documents to return. Default is 4. filter (RedisFilterExpression, optional): Optional metadata filter. Defaults to None. return_metadata (bool, optional): Whether to return metadata. Defaults to True. distance_threshold (Optional[float], optional): Maximum vector distance between selected documents and the query vector. Defaults to None. Returns: List[Document]: A list of documents that are most similar to the query text. """ try: import redis except ImportError as e: raise ImportError( "Could not import redis python package. " "Please install it with `pip install redis`." ) from e if "score_threshold" in kwargs: logger.warning( "score_threshold is deprecated. Use distance_threshold instead." + "score_threshold should only be used in " + "similarity_search_with_relevance_scores." + "score_threshold will be removed in a future release.", ) redis_query, params_dict = self._prepare_query( embedding, k=k, filter=filter, distance_threshold=distance_threshold, with_metadata=return_metadata, with_distance=False, ) # Perform vector search # ignore type because redis-py is wrong about bytes try: results = self.client.ft(self.index_name).search(redis_query, params_dict) # type: ignore except redis.exceptions.ResponseError as e: # split error message and see if it starts with "Syntax" if str(e).split(" ")[0] == "Syntax": raise ValueError( "Query failed with syntax error. " + "This is likely due to malformation of " + "filter, vector, or query argument" ) from e raise e # Prepare document results docs = [] for result in results.docs: metadata = {} if return_metadata: metadata = {"id": result.id} metadata.update(self._collect_metadata(result)) content_key = self._schema.content_key docs.append( Document(page_content=getattr(result, content_key), metadata=metadata) ) return docs
def _collect_metadata(self, result: "Document") -> Dict[str, Any]: """Collect metadata from Redis. Method ensures that there isn't a mismatch between the metadata and the index schema passed to this class by the user or generated by this class. Args: result (Document): redis.commands.search.Document object returned from Redis. Returns: Dict[str, Any]: Collected metadata. """ # new metadata dict as modified by this method meta = {} for key in self._schema.metadata_keys: try: meta[key] = getattr(result, key) except AttributeError: # warning about attribute missing logger.warning( f"Metadata key {key} not found in metadata. " + "Setting to None. \n" + "Metadata fields defined for this instance: " + f"{self._schema.metadata_keys}" ) meta[key] = None return meta def _prepare_query( self, query_embedding: List[float], k: int = 4, filter: Optional[RedisFilterExpression] = None, distance_threshold: Optional[float] = None, with_metadata: bool = True, with_distance: bool = False, ) -> Tuple["Query", Dict[str, Any]]: # Creates Redis query params_dict: Dict[str, Union[str, bytes, float]] = { "vector": _array_to_buffer(query_embedding, self._schema.vector_dtype), } # prepare return fields including score return_fields = [self._schema.content_key] if with_distance: return_fields.append("distance") if with_metadata: return_fields.extend(self._schema.metadata_keys) if distance_threshold: params_dict["distance_threshold"] = distance_threshold return ( self._prepare_range_query( k, filter=filter, return_fields=return_fields ), params_dict, ) return ( self._prepare_vector_query(k, filter=filter, return_fields=return_fields), params_dict, ) def _prepare_range_query( self, k: int, filter: Optional[RedisFilterExpression] = None, return_fields: Optional[List[str]] = None, ) -> "Query": try: from redis.commands.search.query import Query except ImportError as e: raise ImportError( "Could not import redis python package. " "Please install it with `pip install redis`." ) from e return_fields = return_fields or [] vector_key = self._schema.content_vector_key base_query = f"@{vector_key}:[VECTOR_RANGE $distance_threshold $vector]" if filter: base_query = str(filter) + " " + base_query query_string = base_query + "=>{$yield_distance_as: distance}" return ( Query(query_string) .return_fields(*return_fields) .sort_by("distance") .paging(0, k) .dialect(2) ) def _prepare_vector_query( self, k: int, filter: Optional[RedisFilterExpression] = None, return_fields: Optional[List[str]] = None, ) -> "Query": """Prepare query for vector search. Args: k: Number of results to return. filter: Optional metadata filter. Returns: query: Query object. """ try: from redis.commands.search.query import Query except ImportError as e: raise ImportError( "Could not import redis python package. " "Please install it with `pip install redis`." ) from e return_fields = return_fields or [] query_prefix = "*" if filter: query_prefix = f"{str(filter)}" vector_key = self._schema.content_vector_key base_query = f"({query_prefix})=>[KNN {k} @{vector_key} $vector AS distance]" query = ( Query(base_query) .return_fields(*return_fields) .sort_by("distance") .paging(0, k) .dialect(2) ) return query def _get_schema_with_defaults( self, index_schema: Optional[Union[Dict[str, ListOfDict], str, os.PathLike]] = None, vector_schema: Optional[Dict[str, Union[str, int]]] = None, ) -> "RedisModel": # should only be called after init of Redis (so Import handled) from langchain_community.vectorstores.redis.schema import ( RedisModel, read_schema, ) schema = RedisModel() # read in schema (yaml file or dict) and # pass to the Pydantic validators if index_schema: schema_values = read_schema(index_schema) # type: ignore schema = RedisModel(**schema_values) # ensure user did not exclude the content field # no modifications if content field found schema.add_content_field() # if no content_vector field, add vector field to schema # this makes adding a vector field to the schema optional when # the user just wants additional metadata try: # see if user overrode the content vector schema.content_vector # if user overrode the content vector, check if they # also passed vector schema. This won't be used since # the index schema overrode the content vector if vector_schema: logger.warning( "`vector_schema` is ignored since content_vector is " + "overridden in `index_schema`." ) # user did not override content vector except ValueError: # set default vector schema and update with user provided schema # if the user provided any vector_field = self.DEFAULT_VECTOR_SCHEMA.copy() if vector_schema: vector_field.update(vector_schema) # add the vector field either way schema.add_vector_field(vector_field) return schema def _create_index_if_not_exist(self, dim: int = 1536) -> None: try: from redis.commands.search.indexDefinition import ( # type: ignore IndexDefinition, IndexType, ) except ImportError: raise ImportError( "Could not import redis python package. " "Please install it with `pip install redis`." ) # Set vector dimension # can't obtain beforehand because we don't # know which embedding model is being used. self._schema.content_vector.dims = dim # Check if index exists if not check_index_exists(self.client, self.index_name): # Create Redis Index self.client.ft(self.index_name).create_index( fields=self._schema.get_fields(), definition=IndexDefinition( prefix=[self.key_prefix], index_type=IndexType.HASH ), ) def _calculate_fp_distance(self, distance: str) -> float: """Calculate the distance based on the vector datatype Two datatypes supported: - FLOAT32 - FLOAT64 if it's FLOAT32, we need to round the distance to 4 decimal places otherwise, round to 7 decimal places. """ if self._schema.content_vector.datatype == "FLOAT32": return round(float(distance), 4) return round(float(distance), 7) def _check_deprecated_kwargs(self, kwargs: Mapping[str, Any]) -> None: """Check for deprecated kwargs.""" deprecated_kwargs = { "redis_host": "redis_url", "redis_port": "redis_url", "redis_password": "redis_url", "content_key": "index_schema", "vector_key": "vector_schema", "distance_metric": "vector_schema", } for key, value in kwargs.items(): if key in deprecated_kwargs: raise ValueError( f"Keyword argument '{key}' is deprecated. " f"Please use '{deprecated_kwargs[key]}' instead." ) def _select_relevance_score_fn(self) -> Callable[[float], float]: if self.relevance_score_fn: return self.relevance_score_fn metric_map = { "COSINE": self._cosine_relevance_score_fn, "IP": self._max_inner_product_relevance_score_fn, "L2": self._euclidean_relevance_score_fn, } try: return metric_map[self._schema.content_vector.distance_metric] except KeyError: return _default_relevance_score
def _generate_field_schema(data: Dict[str, Any]) -> Dict[str, Any]: """ Generate a schema for the search index in Redis based on the input metadata. Given a dictionary of metadata, this function categorizes each metadata field into one of the three categories: - text: The field contains textual data. - numeric: The field contains numeric data (either integer or float). - tag: The field contains list of tags (strings). Args data (Dict[str, Any]): A dictionary where keys are metadata field names and values are the metadata values. Returns: Dict[str, Any]: A dictionary with three keys "text", "numeric", and "tag". Each key maps to a list of fields that belong to that category. Raises: ValueError: If a metadata field cannot be categorized into any of the three known types. """ result: Dict[str, Any] = { "text": [], "numeric": [], "tag": [], } for key, value in data.items(): # Numeric fields try: int(value) result["numeric"].append({"name": key}) continue except (ValueError, TypeError): pass # None values are not indexed as of now if value is None: continue # if it's a list of strings, we assume it's a tag if isinstance(value, (list, tuple)): if not value or isinstance(value[0], str): result["tag"].append({"name": key}) else: name = type(value[0]).__name__ raise ValueError( f"List/tuple values should contain strings: '{key}': {name}" ) continue # Check if value is string before processing further if isinstance(value, str): result["text"].append({"name": key}) continue # Unable to classify the field value name = type(value).__name__ raise ValueError( "Could not generate Redis index field type mapping " + f"for metadata: '{key}': {name}" ) return result def _prepare_metadata(metadata: Dict[str, Any]) -> Dict[str, Any]: """ Prepare metadata for indexing in Redis by sanitizing its values. - String, integer, and float values remain unchanged. - None or empty values are replaced with empty strings. - Lists/tuples of strings are joined into a single string with a comma separator. Args: metadata (Dict[str, Any]): A dictionary where keys are metadata field names and values are the metadata values. Returns: Dict[str, Any]: A sanitized dictionary ready for indexing in Redis. Raises: ValueError: If any metadata value is not one of the known types (string, int, float, or list of strings). """ def raise_error(key: str, value: Any) -> None: raise ValueError( f"Metadata value for key '{key}' must be a string, int, " + f"float, or list of strings. Got {type(value).__name__}" ) clean_meta: Dict[str, Union[str, float, int]] = {} for key, value in metadata.items(): if value is None: clean_meta[key] = "" continue # No transformation needed if isinstance(value, (str, int, float)): clean_meta[key] = value # if it's a list/tuple of strings, we join it elif isinstance(value, (list, tuple)): if not value or isinstance(value[0], str): clean_meta[key] = REDIS_TAG_SEPARATOR.join(value) else: raise_error(key, value) else: raise_error(key, value) return clean_meta
[docs]class RedisVectorStoreRetriever(VectorStoreRetriever): """Retriever for Redis VectorStore.""" vectorstore: Redis """Redis VectorStore.""" search_type: str = "similarity" """Type of search to perform. Can be either 'similarity', 'similarity_distance_threshold', 'similarity_score_threshold' """ search_kwargs: Dict[str, Any] = { "k": 4, "score_threshold": 0.9, # set to None to avoid distance used in score_threshold search "distance_threshold": None, } """Default search kwargs.""" allowed_search_types = [ "similarity", "similarity_distance_threshold", "similarity_score_threshold", "mmr", ] """Allowed search types.""" class Config: """Configuration for this pydantic object.""" arbitrary_types_allowed = True def _get_relevant_documents( self, query: str, *, run_manager: CallbackManagerForRetrieverRun ) -> List[Document]: if self.search_type == "similarity": docs = self.vectorstore.similarity_search(query, **self.search_kwargs) elif self.search_type == "similarity_distance_threshold": if self.search_kwargs["distance_threshold"] is None: raise ValueError( "distance_threshold must be provided for " + "similarity_distance_threshold retriever" ) docs = self.vectorstore.similarity_search(query, **self.search_kwargs) elif self.search_type == "similarity_score_threshold": docs_and_similarities = ( self.vectorstore.similarity_search_with_relevance_scores( query, **self.search_kwargs ) ) docs = [doc for doc, _ in docs_and_similarities] elif self.search_type == "mmr": docs = self.vectorstore.max_marginal_relevance_search( query, **self.search_kwargs ) else: raise ValueError(f"search_type of {self.search_type} not allowed.") return docs async def _aget_relevant_documents( self, query: str, *, run_manager: AsyncCallbackManagerForRetrieverRun ) -> List[Document]: if self.search_type == "similarity": docs = await self.vectorstore.asimilarity_search( query, **self.search_kwargs ) elif self.search_type == "similarity_distance_threshold": if self.search_kwargs["distance_threshold"] is None: raise ValueError( "distance_threshold must be provided for " + "similarity_distance_threshold retriever" ) docs = await self.vectorstore.asimilarity_search( query, **self.search_kwargs ) elif self.search_type == "similarity_score_threshold": docs_and_similarities = ( await self.vectorstore.asimilarity_search_with_relevance_scores( query, **self.search_kwargs ) ) docs = [doc for doc, _ in docs_and_similarities] elif self.search_type == "mmr": docs = await self.vectorstore.amax_marginal_relevance_search( query, **self.search_kwargs ) else: raise ValueError(f"search_type of {self.search_type} not allowed.") return docs
[docs] def add_documents(self, documents: List[Document], **kwargs: Any) -> List[str]: """Add documents to vectorstore.""" return self.vectorstore.add_documents(documents, **kwargs)
[docs] async def aadd_documents( self, documents: List[Document], **kwargs: Any ) -> List[str]: """Add documents to vectorstore.""" return await self.vectorstore.aadd_documents(documents, **kwargs)