community[major], core[patch], langchain[patch], experimental[patch]: Create langchain-community (#14463)

Moved the following modules to new package langchain-community in a backwards compatible fashion:

```
mv langchain/langchain/adapters community/langchain_community
mv langchain/langchain/callbacks community/langchain_community/callbacks
mv langchain/langchain/chat_loaders community/langchain_community
mv langchain/langchain/chat_models community/langchain_community
mv langchain/langchain/document_loaders community/langchain_community
mv langchain/langchain/docstore community/langchain_community
mv langchain/langchain/document_transformers community/langchain_community
mv langchain/langchain/embeddings community/langchain_community
mv langchain/langchain/graphs community/langchain_community
mv langchain/langchain/llms community/langchain_community
mv langchain/langchain/memory/chat_message_histories community/langchain_community
mv langchain/langchain/retrievers community/langchain_community
mv langchain/langchain/storage community/langchain_community
mv langchain/langchain/tools community/langchain_community
mv langchain/langchain/utilities community/langchain_community
mv langchain/langchain/vectorstores community/langchain_community
mv langchain/langchain/agents/agent_toolkits community/langchain_community
mv langchain/langchain/cache.py community/langchain_community
mv langchain/langchain/adapters community/langchain_community
mv langchain/langchain/callbacks community/langchain_community/callbacks
mv langchain/langchain/chat_loaders community/langchain_community
mv langchain/langchain/chat_models community/langchain_community
mv langchain/langchain/document_loaders community/langchain_community
mv langchain/langchain/docstore community/langchain_community
mv langchain/langchain/document_transformers community/langchain_community
mv langchain/langchain/embeddings community/langchain_community
mv langchain/langchain/graphs community/langchain_community
mv langchain/langchain/llms community/langchain_community
mv langchain/langchain/memory/chat_message_histories community/langchain_community
mv langchain/langchain/retrievers community/langchain_community
mv langchain/langchain/storage community/langchain_community
mv langchain/langchain/tools community/langchain_community
mv langchain/langchain/utilities community/langchain_community
mv langchain/langchain/vectorstores community/langchain_community
mv langchain/langchain/agents/agent_toolkits community/langchain_community
mv langchain/langchain/cache.py community/langchain_community
```

Moved the following to core
```
mv langchain/langchain/utils/json_schema.py core/langchain_core/utils
mv langchain/langchain/utils/html.py core/langchain_core/utils
mv langchain/langchain/utils/strings.py core/langchain_core/utils
cat langchain/langchain/utils/env.py >> core/langchain_core/utils/env.py
rm langchain/langchain/utils/env.py
```

See .scripts/community_split/script_integrations.sh for all changes

libs/community/langchain_community/document_loaders/snowflake_loader.py

@@ -0,0 +1,128 @@
+from __future__ import annotations
+
+from typing import Any, Dict, Iterator, List, Optional, Tuple
+
+from langchain_core.documents import Document
+
+from langchain_community.document_loaders.base import BaseLoader
+
+
+class SnowflakeLoader(BaseLoader):
+    """Load from `Snowflake` API.
+
+    Each document represents one row of the result. The `page_content_columns`
+    are written into the `page_content` of the document. The `metadata_columns`
+    are written into the `metadata` of the document. By default, all columns
+    are written into the `page_content` and none into the `metadata`.
+
+    """
+
+    def __init__(
+        self,
+        query: str,
+        user: str,
+        password: str,
+        account: str,
+        warehouse: str,
+        role: str,
+        database: str,
+        schema: str,
+        parameters: Optional[Dict[str, Any]] = None,
+        page_content_columns: Optional[List[str]] = None,
+        metadata_columns: Optional[List[str]] = None,
+    ):
+        """Initialize Snowflake document loader.
+
+        Args:
+            query: The query to run in Snowflake.
+            user: Snowflake user.
+            password: Snowflake password.
+            account: Snowflake account.
+            warehouse: Snowflake warehouse.
+            role: Snowflake role.
+            database: Snowflake database
+            schema: Snowflake schema
+            parameters: Optional. Parameters to pass to the query.
+            page_content_columns: Optional. Columns written to Document `page_content`.
+            metadata_columns: Optional. Columns written to Document `metadata`.
+        """
+        self.query = query
+        self.user = user
+        self.password = password
+        self.account = account
+        self.warehouse = warehouse
+        self.role = role
+        self.database = database
+        self.schema = schema
+        self.parameters = parameters
+        self.page_content_columns = (
+            page_content_columns if page_content_columns is not None else ["*"]
+        )
+        self.metadata_columns = metadata_columns if metadata_columns is not None else []
+
+    def _execute_query(self) -> List[Dict[str, Any]]:
+        try:
+            import snowflake.connector
+        except ImportError as ex:
+            raise ImportError(
+                "Could not import snowflake-connector-python package. "
+                "Please install it with `pip install snowflake-connector-python`."
+            ) from ex
+
+        conn = snowflake.connector.connect(
+            user=self.user,
+            password=self.password,
+            account=self.account,
+            warehouse=self.warehouse,
+            role=self.role,
+            database=self.database,
+            schema=self.schema,
+            parameters=self.parameters,
+        )
+        try:
+            cur = conn.cursor()
+            cur.execute("USE DATABASE " + self.database)
+            cur.execute("USE SCHEMA " + self.schema)
+            cur.execute(self.query, self.parameters)
+            query_result = cur.fetchall()
+            column_names = [column[0] for column in cur.description]
+            query_result = [dict(zip(column_names, row)) for row in query_result]
+        except Exception as e:
+            print(f"An error occurred: {e}")
+            query_result = []
+        finally:
+            cur.close()
+        return query_result
+
+    def _get_columns(
+        self, query_result: List[Dict[str, Any]]
+    ) -> Tuple[List[str], List[str]]:
+        page_content_columns = (
+            self.page_content_columns if self.page_content_columns else []
+        )
+        metadata_columns = self.metadata_columns if self.metadata_columns else []
+        if page_content_columns is None and query_result:
+            page_content_columns = list(query_result[0].keys())
+        if metadata_columns is None:
+            metadata_columns = []
+        return page_content_columns or [], metadata_columns
+
+    def lazy_load(self) -> Iterator[Document]:
+        query_result = self._execute_query()
+        if isinstance(query_result, Exception):
+            print(f"An error occurred during the query: {query_result}")
+            return []
+        page_content_columns, metadata_columns = self._get_columns(query_result)
+        if "*" in page_content_columns:
+            page_content_columns = list(query_result[0].keys())
+        for row in query_result:
+            page_content = "\n".join(
+                f"{k}: {v}" for k, v in row.items() if k in page_content_columns
+            )
+            metadata = {k: v for k, v in row.items() if k in metadata_columns}
+            doc = Document(page_content=page_content, metadata=metadata)
+            yield doc
+
+    def load(self) -> List[Document]:
+        """Load data into document objects."""
+        return list(self.lazy_load())