mirror of
https://github.com/hwchase17/langchain
synced 2024-11-06 03:20:49 +00:00
119 lines
4.4 KiB
Python
119 lines
4.4 KiB
Python
from __future__ import annotations
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import json
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import logging
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from typing import (
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TYPE_CHECKING,
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Any,
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AsyncIterator,
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Callable,
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Dict,
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Iterator,
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List,
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Optional,
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)
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from langchain_core.documents import Document
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from langchain_community.document_loaders.base import BaseLoader
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from langchain_community.utilities.astradb import _AstraDBEnvironment
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if TYPE_CHECKING:
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from astrapy.db import AstraDB, AsyncAstraDB
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logger = logging.getLogger(__name__)
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class AstraDBLoader(BaseLoader):
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def __init__(
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self,
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collection_name: str,
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*,
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token: Optional[str] = None,
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api_endpoint: Optional[str] = None,
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astra_db_client: Optional[AstraDB] = None,
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async_astra_db_client: Optional[AsyncAstraDB] = None,
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namespace: Optional[str] = None,
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filter_criteria: Optional[Dict[str, Any]] = None,
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projection: Optional[Dict[str, Any]] = None,
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find_options: Optional[Dict[str, Any]] = None,
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nb_prefetched: int = 1000,
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extraction_function: Callable[[Dict], str] = json.dumps,
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) -> None:
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"""Load DataStax Astra DB documents.
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Args:
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collection_name: name of the Astra DB collection to use.
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token: API token for Astra DB usage.
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api_endpoint: full URL to the API endpoint,
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such as `https://<DB-ID>-us-east1.apps.astra.datastax.com`.
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astra_db_client: *alternative to token+api_endpoint*,
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you can pass an already-created 'astrapy.db.AstraDB' instance.
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async_astra_db_client: *alternative to token+api_endpoint*,
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you can pass an already-created 'astrapy.db.AsyncAstraDB' instance.
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namespace: namespace (aka keyspace) where the
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collection is. Defaults to the database's "default namespace".
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filter_criteria: Criteria to filter documents.
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projection: Specifies the fields to return.
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find_options: Additional options for the query.
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nb_prefetched: Max number of documents to pre-fetch. Defaults to 1000.
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extraction_function: Function applied to collection documents to create
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the `page_content` of the LangChain Document. Defaults to `json.dumps`.
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"""
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astra_env = _AstraDBEnvironment(
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token=token,
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api_endpoint=api_endpoint,
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astra_db_client=astra_db_client,
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async_astra_db_client=async_astra_db_client,
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namespace=namespace,
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)
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self.astra_env = astra_env
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self.collection = astra_env.astra_db.collection(collection_name)
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self.collection_name = collection_name
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self.filter = filter_criteria
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self.projection = projection
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self.find_options = find_options or {}
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self.nb_prefetched = nb_prefetched
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self.extraction_function = extraction_function
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def lazy_load(self) -> Iterator[Document]:
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for doc in self.collection.paginated_find(
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filter=self.filter,
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options=self.find_options,
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projection=self.projection,
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sort=None,
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prefetched=self.nb_prefetched,
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):
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yield Document(
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page_content=self.extraction_function(doc),
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metadata={
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"namespace": self.collection.astra_db.namespace,
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"api_endpoint": self.collection.astra_db.base_url,
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"collection": self.collection_name,
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},
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)
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async def aload(self) -> List[Document]:
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"""Load data into Document objects."""
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return [doc async for doc in self.alazy_load()]
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async def alazy_load(self) -> AsyncIterator[Document]:
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async_collection = await self.astra_env.async_astra_db.collection(
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self.collection_name
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)
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async for doc in async_collection.paginated_find(
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filter=self.filter,
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options=self.find_options,
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projection=self.projection,
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sort=None,
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prefetched=self.nb_prefetched,
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):
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yield Document(
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page_content=self.extraction_function(doc),
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metadata={
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"namespace": async_collection.astra_db.namespace,
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"api_endpoint": async_collection.astra_db.base_url,
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"collection": self.collection_name,
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},
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)
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