feat: add SQLDatabaseChain

Close #173

src/backend/langflow/config.yaml

@@ -6,6 +6,7 @@ chains:
   - SeriesCharacterChain
   - MidJourneyPromptChain
   - TimeTravelGuideChain
+  - SQLDatabaseChain
 
 agents:
   - ZeroShotAgent
@@ -122,5 +123,6 @@ utilities:
   - WikipediaAPIWrapper
   - WolframAlphaAPIWrapper
   # - ZapierNLAWrapper
+  - SQLDatabase
 
 dev: false

src/backend/langflow/custom/customs.py

@@ -12,6 +12,9 @@ CUSTOM_NODES = {
         "VectorStoreRouterAgent": nodes.VectorStoreRouterAgentNode(),
         "SQLAgent": nodes.SQLAgentNode(),
     },
+    "utilities": {
+        "SQLDatabase": nodes.SQLDatabaseNode(),
+    },
 }
 
 

src/backend/langflow/graph/base.py

@@ -202,7 +202,11 @@ class Node:
             "VectorStoreRouterAgent",
             "VectorStoreAgent",
             "VectorStoreInfo",
-        ] or self.node_type in ["VectorStoreInfo", "VectorStoreRouterToolkit"]:
+        ] or self.node_type in [
+            "VectorStoreInfo",
+            "VectorStoreRouterToolkit",
+            "SQLDatabase",
+        ]:
             return self._built_object
         return deepcopy(self._built_object)
 

src/backend/langflow/graph/nodes.py

@@ -101,6 +101,10 @@ class ChainNode(Node):
                     self.params[key] = value.build(tools=tools, force=force)
 
             self._build()
+
+        #! Cannot deepcopy SQLDatabaseChain
+        if self.node_type in ["SQLDatabaseChain"]:
+            return self._built_object
         return deepcopy(self._built_object)
 
 

src/backend/langflow/interface/custom_lists.py

@@ -14,6 +14,7 @@ from langchain import (
 )
 from langchain.agents import agent_toolkits
 from langchain.chat_models import ChatOpenAI
+from langchain.sql_database import SQLDatabase
 
 from langflow.interface.importing.utils import import_class
 
@@ -82,3 +83,4 @@ textsplitter_type_to_cls_dict: dict[str, Any] = dict(
 utility_type_to_cls_dict: dict[str, Any] = dict(
     inspect.getmembers(utilities, inspect.isclass)
 )
+utility_type_to_cls_dict["SQLDatabase"] = SQLDatabase

src/backend/langflow/interface/importing/utils.py

@@ -44,6 +44,7 @@ def import_by_type(_type: str, name: str) -> Any:
         "vectorstores": import_vectorstore,
         "documentloaders": import_documentloader,
         "textsplitters": import_textsplitter,
+        "utilities": import_utility,
     }
     if _type == "llms":
         key = "chat" if "chat" in name.lower() else "llm"
@@ -131,10 +132,16 @@ def import_vectorstore(vectorstore: str) -> Any:
 
 def import_documentloader(documentloader: str) -> Any:
     """Import documentloader from documentloader name"""
-
     return import_class(f"langchain.document_loaders.{documentloader}")
 
 
 def import_textsplitter(textsplitter: str) -> Any:
     """Import textsplitter from textsplitter name"""
     return import_class(f"langchain.text_splitter.{textsplitter}")
+
+
+def import_utility(utility: str) -> Any:
+    """Import utility from utility name"""
+    if utility == "SQLDatabase":
+        return import_class(f"langchain.sql_database.{utility}")
+    return import_class(f"langchain.utilities.{utility}")

src/backend/langflow/interface/loading.py

@@ -75,6 +75,9 @@ def instantiate_class(node_type: str, base_type: str, params: Dict) -> Any:
         documents = params.pop("documents")
         text_splitter = class_object(**params)
         return text_splitter.split_documents(documents)
+    elif base_type == "utilities":
+        if node_type == "SQLDatabase":
+            return class_object.from_uri(params.pop("uri"))
 
     return class_object(**params)
 

src/backend/langflow/interface/tools/base.py

@@ -1,4 +1,3 @@
-import inspect
 from typing import Dict, List, Optional
 
 from langchain.agents.load_tools import (

src/backend/langflow/interface/utilities/base.py

@@ -1,5 +1,6 @@
 from typing import Dict, List, Optional
 
+from langflow.custom.customs import get_custom_nodes
 from langflow.interface.base import LangChainTypeCreator
 from langflow.interface.custom_lists import utility_type_to_cls_dict
 from langflow.settings import settings
@@ -17,6 +18,8 @@ class UtilityCreator(LangChainTypeCreator):
     def get_signature(self, name: str) -> Optional[Dict]:
         """Get the signature of a utility."""
         try:
+            if name in get_custom_nodes(self.type_name).keys():
+                return get_custom_nodes(self.type_name)[name]
             return build_template_from_class(name, utility_type_to_cls_dict)
         except ValueError as exc:
             raise ValueError(f"Utility {name} not found") from exc

src/backend/langflow/template/nodes.py

@@ -256,6 +256,29 @@ class CSVAgentNode(FrontendNode):
         return super().to_dict()
 
 
+class SQLDatabaseNode(FrontendNode):
+    name: str = "SQLDatabase"
+    template: Template = Template(
+        type_name="sql_database",
+        fields=[
+            TemplateField(
+                field_type="str",
+                required=True,
+                is_list=False,
+                show=True,
+                multiline=False,
+                value="",
+                name="uri",
+            ),
+        ],
+    )
+    description: str = """SQLAlchemy wrapper around a database."""
+    base_classes: list[str] = ["SQLDatabase"]
+
+    def to_dict(self):
+        return super().to_dict()
+
+
 class VectorStoreAgentNode(FrontendNode):
     name: str = "VectorStoreAgent"
     template: Template = Template(