mirror of
https://github.com/hwchase17/langchain
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1b4dcf22f3
**Description:** - Added Amazon DocumentDB Vector Search integration (HNSW index) - Added integration tests - Updated AWS documentation with DocumentDB Vector Search instructions - Added notebook for DocumentDB integration with example usage --------- Co-authored-by: EC2 Default User <ec2-user@ip-172-31-95-226.ec2.internal>
362 lines
12 KiB
Python
362 lines
12 KiB
Python
from __future__ import annotations
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import logging
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from enum import Enum
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from typing import (
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TYPE_CHECKING,
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Any,
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Dict,
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Generator,
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Iterable,
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List,
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Optional,
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TypeVar,
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Union,
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)
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from langchain_core.documents import Document
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from langchain_core.vectorstores import VectorStore
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if TYPE_CHECKING:
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from langchain_core.embeddings import Embeddings
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from pymongo.collection import Collection
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# Before Python 3.11 native StrEnum is not available
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class DocumentDBSimilarityType(str, Enum):
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"""DocumentDB Similarity Type as enumerator."""
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COS = "cosine"
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"""Cosine similarity"""
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DOT = "dotProduct"
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"""Dot product"""
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EUC = "euclidean"
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"""Euclidean distance"""
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DocumentDBDocumentType = TypeVar("DocumentDBDocumentType", bound=Dict[str, Any])
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logger = logging.getLogger(__name__)
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DEFAULT_INSERT_BATCH_SIZE = 128
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class DocumentDBVectorSearch(VectorStore):
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"""`Amazon DocumentDB (with MongoDB compatibility)` vector store.
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Please refer to the official Vector Search documentation for more details:
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https://docs.aws.amazon.com/documentdb/latest/developerguide/vector-search.html
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To use, you should have both:
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- the ``pymongo`` python package installed
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- a connection string and credentials associated with a DocumentDB cluster
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Example:
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. code-block:: python
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from langchain_community.vectorstores import DocumentDBVectorSearch
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from langchain_community.embeddings.openai import OpenAIEmbeddings
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from pymongo import MongoClient
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mongo_client = MongoClient("<YOUR-CONNECTION-STRING>")
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collection = mongo_client["<db_name>"]["<collection_name>"]
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embeddings = OpenAIEmbeddings()
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vectorstore = DocumentDBVectorSearch(collection, embeddings)
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"""
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def __init__(
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self,
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collection: Collection[DocumentDBDocumentType],
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embedding: Embeddings,
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*,
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index_name: str = "vectorSearchIndex",
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text_key: str = "textContent",
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embedding_key: str = "vectorContent",
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):
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"""Constructor for DocumentDBVectorSearch
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Args:
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collection: MongoDB collection to add the texts to.
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embedding: Text embedding model to use.
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index_name: Name of the Vector Search index.
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text_key: MongoDB field that will contain the text
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for each document.
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embedding_key: MongoDB field that will contain the embedding
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for each document.
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"""
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self._collection = collection
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self._embedding = embedding
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self._index_name = index_name
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self._text_key = text_key
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self._embedding_key = embedding_key
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self._similarity_type = DocumentDBSimilarityType.COS
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@property
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def embeddings(self) -> Embeddings:
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return self._embedding
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def get_index_name(self) -> str:
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"""Returns the index name
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Returns:
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Returns the index name
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"""
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return self._index_name
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@classmethod
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def from_connection_string(
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cls,
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connection_string: str,
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namespace: str,
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embedding: Embeddings,
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**kwargs: Any,
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) -> DocumentDBVectorSearch:
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"""Creates an Instance of DocumentDBVectorSearch from a Connection String
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Args:
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connection_string: The DocumentDB cluster endpoint connection string
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namespace: The namespace (database.collection)
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embedding: The embedding utility
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**kwargs: Dynamic keyword arguments
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Returns:
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an instance of the vector store
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"""
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try:
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from pymongo import MongoClient
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except ImportError:
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raise ImportError(
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"Could not import pymongo, please install it with "
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"`pip install pymongo`."
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)
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client: MongoClient = MongoClient(connection_string)
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db_name, collection_name = namespace.split(".")
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collection = client[db_name][collection_name]
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return cls(collection, embedding, **kwargs)
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def index_exists(self) -> bool:
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"""Verifies if the specified index name during instance
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construction exists on the collection
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Returns:
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Returns True on success and False if no such index exists
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on the collection
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"""
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cursor = self._collection.list_indexes()
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index_name = self._index_name
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for res in cursor:
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current_index_name = res.pop("name")
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if current_index_name == index_name:
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return True
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return False
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def delete_index(self) -> None:
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"""Deletes the index specified during instance construction if it exists"""
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if self.index_exists():
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self._collection.drop_index(self._index_name)
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# Raises OperationFailure on an error (e.g. trying to drop
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# an index that does not exist)
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def create_index(
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self,
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dimensions: int = 1536,
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similarity: DocumentDBSimilarityType = DocumentDBSimilarityType.COS,
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m: int = 16,
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ef_construction: int = 64,
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) -> dict[str, Any]:
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"""Creates an index using the index name specified at
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instance construction
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Args:
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dimensions: Number of dimensions for vector similarity.
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The maximum number of supported dimensions is 2000
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similarity: Similarity algorithm to use with the HNSW index.
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m: Specifies the max number of connections for an HNSW index.
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Large impact on memory consumption.
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ef_construction: Specifies the size of the dynamic candidate list
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for constructing the graph for HNSW index. Higher values lead
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to more accurate results but slower indexing speed.
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Possible options are:
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- DocumentDBSimilarityType.COS (cosine distance),
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- DocumentDBSimilarityType.EUC (Euclidean distance), and
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- DocumentDBSimilarityType.DOT (dot product).
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Returns:
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An object describing the created index
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"""
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self._similarity_type = similarity
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# prepare the command
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create_index_commands = {
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"createIndexes": self._collection.name,
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"indexes": [
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{
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"name": self._index_name,
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"key": {self._embedding_key: "vector"},
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"vectorOptions": {
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"type": "hnsw",
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"similarity": similarity,
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"dimensions": dimensions,
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"m": m,
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"efConstruction": ef_construction,
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},
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}
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],
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}
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# retrieve the database object
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current_database = self._collection.database
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# invoke the command from the database object
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create_index_responses: dict[str, Any] = current_database.command(
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create_index_commands
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)
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return create_index_responses
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def add_texts(
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self,
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texts: Iterable[str],
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metadatas: Optional[List[Dict[str, Any]]] = None,
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**kwargs: Any,
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) -> List:
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batch_size = kwargs.get("batch_size", DEFAULT_INSERT_BATCH_SIZE)
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_metadatas: Union[List, Generator] = metadatas or ({} for _ in texts)
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texts_batch = []
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metadatas_batch = []
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result_ids = []
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for i, (text, metadata) in enumerate(zip(texts, _metadatas)):
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texts_batch.append(text)
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metadatas_batch.append(metadata)
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if (i + 1) % batch_size == 0:
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result_ids.extend(self._insert_texts(texts_batch, metadatas_batch))
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texts_batch = []
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metadatas_batch = []
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if texts_batch:
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result_ids.extend(self._insert_texts(texts_batch, metadatas_batch))
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return result_ids
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def _insert_texts(self, texts: List[str], metadatas: List[Dict[str, Any]]) -> List:
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"""Used to Load Documents into the collection
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Args:
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texts: The list of documents strings to load
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metadatas: The list of metadata objects associated with each document
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Returns:
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"""
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# If the text is empty, then exit early
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if not texts:
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return []
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# Embed and create the documents
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embeddings = self._embedding.embed_documents(texts)
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to_insert = [
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{self._text_key: t, self._embedding_key: embedding, **m}
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for t, m, embedding in zip(texts, metadatas, embeddings)
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]
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# insert the documents in DocumentDB
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insert_result = self._collection.insert_many(to_insert) # type: ignore
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return insert_result.inserted_ids
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@classmethod
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def from_texts(
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cls,
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texts: List[str],
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embedding: Embeddings,
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metadatas: Optional[List[dict]] = None,
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collection: Optional[Collection[DocumentDBDocumentType]] = None,
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**kwargs: Any,
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) -> DocumentDBVectorSearch:
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if collection is None:
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raise ValueError("Must provide 'collection' named parameter.")
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vectorstore = cls(collection, embedding, **kwargs)
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vectorstore.add_texts(texts, metadatas=metadatas)
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return vectorstore
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def delete(self, ids: Optional[List[str]] = None, **kwargs: Any) -> Optional[bool]:
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if ids is None:
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raise ValueError("No document ids provided to delete.")
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for document_id in ids:
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self.delete_document_by_id(document_id)
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return True
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def delete_document_by_id(self, document_id: Optional[str] = None) -> None:
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"""Removes a Specific Document by Id
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Args:
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document_id: The document identifier
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"""
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try:
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from bson.objectid import ObjectId
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except ImportError as e:
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raise ImportError(
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"Unable to import bson, please install with `pip install bson`."
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) from e
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if document_id is None:
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raise ValueError("No document id provided to delete.")
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self._collection.delete_one({"_id": ObjectId(document_id)})
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def _similarity_search_without_score(
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self, embeddings: List[float], k: int = 4, ef_search: int = 40
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) -> List[Document]:
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"""Returns a list of documents.
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Args:
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embeddings: The query vector
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k: the number of documents to return
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ef_search: Specifies the size of the dynamic candidate list
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that HNSW index uses during search. A higher value of
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efSearch provides better recall at cost of speed.
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Returns:
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A list of documents closest to the query vector
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"""
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pipeline: List[dict[str, Any]] = [
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{
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"$search": {
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"vectorSearch": {
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"vector": embeddings,
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"path": self._embedding_key,
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"similarity": self._similarity_type,
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"k": k,
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"efSearch": ef_search,
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}
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}
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}
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]
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cursor = self._collection.aggregate(pipeline)
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docs = []
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for res in cursor:
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text = res.pop(self._text_key)
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docs.append(Document(page_content=text, metadata=res))
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return docs
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def similarity_search(
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self,
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query: str,
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k: int = 4,
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ef_search: int = 40,
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**kwargs: Any,
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) -> List[Document]:
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embeddings = self._embedding.embed_query(query)
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docs = self._similarity_search_without_score(
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embeddings=embeddings, k=k, ef_search=ef_search
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)
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return [doc for doc in docs]
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