mirror of
https://github.com/hwchase17/langchain
synced 2024-11-10 01:10:59 +00:00
129 lines
4.7 KiB
Python
129 lines
4.7 KiB
Python
from __future__ import annotations
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from typing import Any, Dict, Iterator, List, Optional, Tuple
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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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class SnowflakeLoader(BaseLoader):
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"""Load from `Snowflake` API.
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Each document represents one row of the result. The `page_content_columns`
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are written into the `page_content` of the document. The `metadata_columns`
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are written into the `metadata` of the document. By default, all columns
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are written into 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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query: str,
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user: str,
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password: str,
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account: str,
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warehouse: str,
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role: str,
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database: str,
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schema: str,
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parameters: Optional[Dict[str, Any]] = None,
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page_content_columns: Optional[List[str]] = None,
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metadata_columns: Optional[List[str]] = None,
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):
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"""Initialize Snowflake document loader.
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Args:
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query: The query to run in Snowflake.
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user: Snowflake user.
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password: Snowflake password.
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account: Snowflake account.
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warehouse: Snowflake warehouse.
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role: Snowflake role.
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database: Snowflake database
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schema: Snowflake schema
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parameters: Optional. Parameters to pass to the query.
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page_content_columns: Optional. Columns written to Document `page_content`.
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metadata_columns: Optional. Columns written to Document `metadata`.
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"""
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self.query = query
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self.user = user
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self.password = password
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self.account = account
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self.warehouse = warehouse
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self.role = role
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self.database = database
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self.schema = schema
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self.parameters = parameters
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self.page_content_columns = (
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page_content_columns if page_content_columns is not None else ["*"]
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)
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self.metadata_columns = metadata_columns if metadata_columns is not None else []
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def _execute_query(self) -> List[Dict[str, Any]]:
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try:
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import snowflake.connector
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except ImportError as ex:
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raise ImportError(
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"Could not import snowflake-connector-python package. "
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"Please install it with `pip install snowflake-connector-python`."
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) from ex
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conn = snowflake.connector.connect(
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user=self.user,
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password=self.password,
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account=self.account,
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warehouse=self.warehouse,
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role=self.role,
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database=self.database,
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schema=self.schema,
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parameters=self.parameters,
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)
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try:
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cur = conn.cursor()
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cur.execute("USE DATABASE " + self.database)
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cur.execute("USE SCHEMA " + self.schema)
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cur.execute(self.query, self.parameters)
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query_result = cur.fetchall()
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column_names = [column[0] for column in cur.description]
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query_result = [dict(zip(column_names, row)) for row in query_result]
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except Exception as e:
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print(f"An error occurred: {e}") # noqa: T201
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query_result = []
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finally:
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cur.close()
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return query_result
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def _get_columns(
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self, query_result: List[Dict[str, Any]]
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) -> Tuple[List[str], List[str]]:
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page_content_columns = (
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self.page_content_columns if self.page_content_columns else []
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)
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metadata_columns = self.metadata_columns if self.metadata_columns else []
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if page_content_columns is None and query_result:
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page_content_columns = list(query_result[0].keys())
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if metadata_columns is None:
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metadata_columns = []
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return page_content_columns or [], metadata_columns
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def lazy_load(self) -> Iterator[Document]:
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query_result = self._execute_query()
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if isinstance(query_result, Exception):
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print(f"An error occurred during the query: {query_result}") # noqa: T201
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return []
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page_content_columns, metadata_columns = self._get_columns(query_result)
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if "*" in page_content_columns:
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page_content_columns = list(query_result[0].keys())
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for row in query_result:
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page_content = "\n".join(
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f"{k}: {v}" for k, v in row.items() if k in page_content_columns
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)
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metadata = {k: v for k, v in row.items() if k in metadata_columns}
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doc = Document(page_content=page_content, metadata=metadata)
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yield doc
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def load(self) -> List[Document]:
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"""Load data into document objects."""
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return list(self.lazy_load())
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