from __future__ import annotations
import json
import logging
import uuid
from typing import Any, Iterable, List, Optional, Type
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
logger = logging.getLogger(__name__)
def _uuid_key() -> str:
return uuid.uuid4().hex
[docs]class Tair(VectorStore):
"""`Tair` vector store."""
[docs] def __init__(
self,
embedding_function: Embeddings,
url: str,
index_name: str,
content_key: str = "content",
metadata_key: str = "metadata",
search_params: Optional[dict] = None,
**kwargs: Any,
):
self.embedding_function = embedding_function
self.index_name = index_name
try:
from tair import Tair as TairClient
except ImportError:
raise ImportError(
"Could not import tair python package. "
"Please install it with `pip install tair`."
)
try:
# connect to tair from url
client = TairClient.from_url(url, **kwargs)
except ValueError as e:
raise ValueError(f"Tair failed to connect: {e}")
self.client = client
self.content_key = content_key
self.metadata_key = metadata_key
self.search_params = search_params
@property
def embeddings(self) -> Embeddings:
return self.embedding_function
[docs] def create_index_if_not_exist(
self,
dim: int,
distance_type: str,
index_type: str,
data_type: str,
**kwargs: Any,
) -> bool:
index = self.client.tvs_get_index(self.index_name)
if index is not None:
logger.info("Index already exists")
return False
self.client.tvs_create_index(
self.index_name,
dim,
distance_type,
index_type,
data_type,
**kwargs,
)
return True
[docs] def add_texts(
self,
texts: Iterable[str],
metadatas: Optional[List[dict]] = None,
**kwargs: Any,
) -> List[str]:
"""Add texts data to an existing index."""
ids = []
keys = kwargs.get("keys", None)
use_hybrid_search = False
index = self.client.tvs_get_index(self.index_name)
if index is not None and index.get("lexical_algorithm") == "bm25":
use_hybrid_search = True
# Write data to tair
pipeline = self.client.pipeline(transaction=False)
embeddings = self.embedding_function.embed_documents(list(texts))
for i, text in enumerate(texts):
# Use provided key otherwise use default key
key = keys[i] if keys else _uuid_key()
metadata = metadatas[i] if metadatas else {}
if use_hybrid_search:
# tair use TEXT attr hybrid search
pipeline.tvs_hset(
self.index_name,
key,
embeddings[i],
False,
**{
"TEXT": text,
self.content_key: text,
self.metadata_key: json.dumps(metadata),
},
)
else:
pipeline.tvs_hset(
self.index_name,
key,
embeddings[i],
False,
**{
self.content_key: text,
self.metadata_key: json.dumps(metadata),
},
)
ids.append(key)
pipeline.execute()
return ids
[docs] def similarity_search(
self, query: str, k: int = 4, **kwargs: Any
) -> List[Document]:
"""
Returns the most similar indexed documents to the query text.
Args:
query (str): The query text for which to find similar documents.
k (int): The number of documents to return. Default is 4.
Returns:
List[Document]: A list of documents that are most similar to the query text.
"""
# Creates embedding vector from user query
embedding = self.embedding_function.embed_query(query)
keys_and_scores = self.client.tvs_knnsearch(
self.index_name, k, embedding, False, None, **kwargs
)
pipeline = self.client.pipeline(transaction=False)
for key, _ in keys_and_scores:
pipeline.tvs_hmget(
self.index_name, key, self.metadata_key, self.content_key
)
docs = pipeline.execute()
return [
Document(
page_content=d[1],
metadata=json.loads(d[0]),
)
for d in docs
]
[docs] @classmethod
def from_texts(
cls: Type[Tair],
texts: List[str],
embedding: Embeddings,
metadatas: Optional[List[dict]] = None,
index_name: str = "langchain",
content_key: str = "content",
metadata_key: str = "metadata",
**kwargs: Any,
) -> Tair:
try:
from tair import tairvector
except ImportError:
raise ImportError(
"Could not import tair python package. "
"Please install it with `pip install tair`."
)
url = get_from_dict_or_env(kwargs, "tair_url", "TAIR_URL")
if "tair_url" in kwargs:
kwargs.pop("tair_url")
distance_type = tairvector.DistanceMetric.InnerProduct
if "distance_type" in kwargs:
distance_type = kwargs.pop("distance_type")
index_type = tairvector.IndexType.HNSW
if "index_type" in kwargs:
index_type = kwargs.pop("index_type")
data_type = tairvector.DataType.Float32
if "data_type" in kwargs:
data_type = kwargs.pop("data_type")
index_params = {}
if "index_params" in kwargs:
index_params = kwargs.pop("index_params")
search_params = {}
if "search_params" in kwargs:
search_params = kwargs.pop("search_params")
keys = None
if "keys" in kwargs:
keys = kwargs.pop("keys")
try:
tair_vector_store = cls(
embedding,
url,
index_name,
content_key=content_key,
metadata_key=metadata_key,
search_params=search_params,
**kwargs,
)
except ValueError as e:
raise ValueError(f"tair failed to connect: {e}")
# Create embeddings for documents
embeddings = embedding.embed_documents(texts)
tair_vector_store.create_index_if_not_exist(
len(embeddings[0]),
distance_type,
index_type,
data_type,
**index_params,
)
tair_vector_store.add_texts(texts, metadatas, keys=keys)
return tair_vector_store
[docs] @classmethod
def from_documents(
cls,
documents: List[Document],
embedding: Embeddings,
metadatas: Optional[List[dict]] = None,
index_name: str = "langchain",
content_key: str = "content",
metadata_key: str = "metadata",
**kwargs: Any,
) -> Tair:
texts = [d.page_content for d in documents]
metadatas = [d.metadata for d in documents]
return cls.from_texts(
texts, embedding, metadatas, index_name, content_key, metadata_key, **kwargs
)
[docs] @staticmethod
def drop_index(
index_name: str = "langchain",
**kwargs: Any,
) -> bool:
"""
Drop an existing index.
Args:
index_name (str): Name of the index to drop.
Returns:
bool: True if the index is dropped successfully.
"""
try:
from tair import Tair as TairClient
except ImportError:
raise ImportError(
"Could not import tair python package. "
"Please install it with `pip install tair`."
)
url = get_from_dict_or_env(kwargs, "tair_url", "TAIR_URL")
try:
if "tair_url" in kwargs:
kwargs.pop("tair_url")
client = TairClient.from_url(url=url, **kwargs)
except ValueError as e:
raise ValueError(f"Tair connection error: {e}")
# delete index
ret = client.tvs_del_index(index_name)
if ret == 0:
# index not exist
logger.info("Index does not exist")
return False
return True
[docs] @classmethod
def from_existing_index(
cls,
embedding: Embeddings,
index_name: str = "langchain",
content_key: str = "content",
metadata_key: str = "metadata",
**kwargs: Any,
) -> Tair:
"""Connect to an existing Tair index."""
url = get_from_dict_or_env(kwargs, "tair_url", "TAIR_URL")
search_params = {}
if "search_params" in kwargs:
search_params = kwargs.pop("search_params")
return cls(
embedding,
url,
index_name,
content_key=content_key,
metadata_key=metadata_key,
search_params=search_params,
**kwargs,
)
