mirror of
https://github.com/coleam00/ai-agents-masterclass.git
synced 2025-11-29 08:33:16 +00:00
123 lines
3.6 KiB
Python
123 lines
3.6 KiB
Python
from langgraph.graph.message import AnyMessage, add_messages
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from langgraph.checkpoint.aiosqlite import AsyncSqliteSaver
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from langchain_core.runnables import RunnableConfig
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from langgraph.graph import END, StateGraph
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from typing_extensions import TypedDict
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from typing import Annotated, Literal, Dict
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from dotenv import load_dotenv
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import os
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from langchain_openai import ChatOpenAI
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from langchain_anthropic import ChatAnthropic
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from langchain_core.messages import ToolMessage
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from tools import available_functions
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load_dotenv()
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model = os.getenv('LLM_MODEL', 'gpt-4o')
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tools = [tool for _, tool in available_functions.items()]
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chatbot = ChatOpenAI(model=model, streaming=True) if "gpt" in model.lower() else ChatAnthropic(model=model, streaming=True)
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chatbot_with_tools = chatbot.bind_tools(tools)
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### State
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class GraphState(TypedDict):
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"""
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Represents the state of our graph.
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Attributes:
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messages: List of chat messages.
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"""
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messages: Annotated[list[AnyMessage], add_messages]
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async def call_model(state: GraphState, config: RunnableConfig) -> Dict[str, AnyMessage]:
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"""
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Function that calls the model to generate a response.
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Args:
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state (GraphState): The current graph state
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Returns:
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dict: The updated state with a new AI message
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"""
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print("---CALL MODEL---")
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messages = state["messages"]
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# Invoke the chatbot with the binded tools
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response = await chatbot_with_tools.ainvoke(messages, config)
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print("Response from model:", response)
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# We return an object because this will get added to the existing list
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return {"messages": response}
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def tool_node(state: GraphState) -> Dict[str, AnyMessage]:
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"""
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Function that handles all tool calls.
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Args:
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state (GraphState): The current graph state
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Returns:
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dict: The updated state with tool messages
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"""
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print("---TOOL NODE---")
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messages = state["messages"]
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last_message = messages[-1] if messages else None
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outputs = []
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if last_message and last_message.tool_calls:
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for call in last_message.tool_calls:
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tool = available_functions.get(call['name'], None)
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if tool is None:
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raise Exception(f"Tool '{call['name']}' not found.")
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output = tool.invoke(call['args'])
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outputs.append(ToolMessage(
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output if isinstance(output, str) else json.dumps(output),
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tool_call_id=call['id']
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))
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return {'messages': outputs}
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def should_continue(state: GraphState) -> Literal["__end__", "tools"]:
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"""
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Determine whether to continue or end the workflow based on if there are tool calls to make.
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Args:
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state (GraphState): The current graph state
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Returns:
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str: The next node to execute or END
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"""
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print("---SHOULD CONTINUE---")
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messages = state["messages"]
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last_message = messages[-1] if messages else None
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# If there is no function call, then we finish
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if not last_message or not last_message.tool_calls:
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return END
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else:
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return "tools"
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def get_runnable():
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workflow = StateGraph(GraphState)
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# Define the nodes and how they connect
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workflow.add_node("agent", call_model)
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workflow.add_node("tools", tool_node)
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workflow.set_entry_point("agent")
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workflow.add_conditional_edges(
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"agent",
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should_continue
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)
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workflow.add_edge("tools", "agent")
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# Compile the LangGraph graph into a runnable
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memory = AsyncSqliteSaver.from_conn_string(":memory:")
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app = workflow.compile(checkpointer=memory)
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return app |