mirror of
https://github.com/hwchase17/langchain
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97 lines
3.4 KiB
Python
97 lines
3.4 KiB
Python
import logging
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from typing import Iterator, List, Optional
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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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logger = logging.getLogger(__name__)
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class CouchbaseLoader(BaseLoader):
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"""Load documents from `Couchbase`.
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Each document represents one row of the result. The `page_content_fields` are
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written into the `page_content`of the document. The `metadata_fields` are written
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into the `metadata` of the document. By default, all columns are written into
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the `page_content` and none into the `metadata`.
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"""
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def __init__(
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self,
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connection_string: str,
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db_username: str,
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db_password: str,
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query: str,
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*,
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page_content_fields: Optional[List[str]] = None,
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metadata_fields: Optional[List[str]] = None,
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) -> None:
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"""Initialize Couchbase document loader.
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Args:
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connection_string (str): The connection string to the Couchbase cluster.
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db_username (str): The username to connect to the Couchbase cluster.
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db_password (str): The password to connect to the Couchbase cluster.
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query (str): The SQL++ query to execute.
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page_content_fields (Optional[List[str]]): The columns to write into the
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`page_content` field of the document. By default, all columns are
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written.
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metadata_fields (Optional[List[str]]): The columns to write into the
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`metadata` field of the document. By default, no columns are written.
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"""
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try:
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from couchbase.auth import PasswordAuthenticator
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from couchbase.cluster import Cluster
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from couchbase.options import ClusterOptions
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except ImportError as e:
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raise ImportError(
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"Could not import couchbase package."
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"Please install couchbase SDK with `pip install couchbase`."
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) from e
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if not connection_string:
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raise ValueError("connection_string must be provided.")
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if not db_username:
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raise ValueError("db_username must be provided.")
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if not db_password:
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raise ValueError("db_password must be provided.")
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auth = PasswordAuthenticator(
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db_username,
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db_password,
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)
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self.cluster: Cluster = Cluster(connection_string, ClusterOptions(auth))
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self.query = query
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self.page_content_fields = page_content_fields
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self.metadata_fields = metadata_fields
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def lazy_load(self) -> Iterator[Document]:
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"""Load Couchbase data into Document objects lazily."""
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from datetime import timedelta
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# Ensure connection to Couchbase cluster
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self.cluster.wait_until_ready(timedelta(seconds=5))
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# Run SQL++ Query
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result = self.cluster.query(self.query)
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for row in result:
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metadata_fields = self.metadata_fields
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page_content_fields = self.page_content_fields
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if not page_content_fields:
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page_content_fields = list(row.keys())
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if not metadata_fields:
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metadata_fields = []
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metadata = {field: row[field] for field in metadata_fields}
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document = "\n".join(
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f"{k}: {v}" for k, v in row.items() if k in page_content_fields
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)
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yield (Document(page_content=document, metadata=metadata))
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