Langgraph update (#131)

examples/langchain/studio/graph.py

@@ -3,9 +3,9 @@ from datetime import datetime
 
 from configuration import AgentConfigurable
 from langchain_arcade import ArcadeToolManager
-from langchain_core.messages import HumanMessage, ToolMessage
 from langchain_core.prompts import ChatPromptTemplate
 from langchain_openai import ChatOpenAI
+from langgraph.errors import NodeInterrupt
 from langgraph.graph import END, START, MessagesState, StateGraph
 from langgraph.prebuilt import ToolNode
 
@@ -34,6 +34,10 @@ model = ChatOpenAI(model="gpt-4o", api_key=openai_api_key).bind_tools(tools)
 prompted_model = prompt | model
 
 
+class AgentState(MessagesState):
+    auth_url: str | None = None
+
+
 def call_agent(state):
     """Define the agent function that invokes the model"""
     messages = state["messages"]
@@ -42,66 +46,53 @@ def call_agent(state):
     return {"messages": [response]}
 
 
-def should_continue(state: MessagesState, config: dict):
+def should_continue(state: AgentState, config: dict):
     """Function to determine the next step based on the model's response"""
     last_message = state["messages"][-1]
     if last_message.tool_calls:
-        user_id = config["configurable"].get("user_id")
-        tool_name = state["messages"][-1].tool_calls[0]["name"]
-        auth_response = toolkit.authorize(tool_name, user_id)
-        if auth_response.status == "completed":
-            return "tools"
-        else:
-            # If the tool requires authorization, proceed to the authorization step
-            return "authorization"
+        return "check_auth"
     # If no tool calls are present, end the workflow
     return END
 
 
-def wait_for_auth(state: MessagesState):
-    last_message = state["messages"][-1]
-    if isinstance(last_message, HumanMessage):
-        return "agent"
-    return "tools"
+def check_auth(state: AgentState, config: dict):
+    user_id = config["configurable"].get("user_id")
+    tool_name = state["messages"][-1].tool_calls[0]["name"]
+    auth_response = toolkit.authorize(tool_name, user_id)
+    if auth_response.status != "completed":
+        return {"auth_url": auth_response.authorization_url}
+    else:
+        return {"auth_url": None}
 
 
-def authorize(state: MessagesState, config: dict):
+def authorize(state: AgentState, config: dict):
     """Function to handle tool authorization"""
     user_id = config["configurable"].get("user_id")
     tool_name = state["messages"][-1].tool_calls[0]["name"]
     auth_response = toolkit.authorize(tool_name, user_id)
-
-    auth_message = (
-        f"Please authorize the application in your browser:\n\n {auth_response.authorization_url}"
-    )
-    tool_call_id = state["messages"][-1].tool_calls[0]["id"]
-    response = ToolMessage(
-        content=auth_message,
-        tool_call_id=tool_call_id,
-    )
-    # Add the new message to the message history and add a new human message
-    # saying that the agent should try again
-    try_message = HumanMessage(
-        content="Please try the previous tool call again now that you are authorized."
-    )
-    return {"messages": [response, try_message]}
+    if auth_response.status != "completed":
+        auth_message = (
+            f"Please authorize the application in your browser:\n\n {state.get('auth_url')}"
+        )
+        raise NodeInterrupt(auth_message)
 
 
 # Build the workflow graph
-workflow = StateGraph(MessagesState, AgentConfigurable)
+workflow = StateGraph(AgentState, AgentConfigurable)
 
 # Add nodes to the graph
 workflow.add_node("agent", call_agent)
 workflow.add_node("tools", tool_node)
 workflow.add_node("authorization", authorize)
-# workflow.add_node("wait_for_auth", wait_for_auth)
+workflow.add_node("check_auth", check_auth)
 
 # Define the edges and control flow
 workflow.add_edge(START, "agent")
-workflow.add_conditional_edges("agent", should_continue, ["authorization", "tools", END])
-workflow.add_edge("authorization", "agent")
+workflow.add_conditional_edges("agent", should_continue, ["check_auth", END])
+workflow.add_edge("check_auth", "authorization")
+workflow.add_edge("authorization", "tools")
 workflow.add_edge("tools", "agent")
 
 # Compile the graph with an interrupt after the authorization node
 # so that we can prompt the user to authorize the application
-graph = workflow.compile(interrupt_after=["authorization"])
+graph = workflow.compile()