Get current state of the Langgraph graph outside of the Nodes (inside the main forloop)

[Sulomus]

We can access the state of the graph inside each of the Nodes such as like this:

async def thought(state: PlanExecute):
    # example node
    state["messages"] ...

But I want to access the state here:

app = workflow.compile()

async for event in app.astream_events(input={"message_history": conversation_buffer.messages}, version="v2"):
    app.state() 

Where is the state saved inside of the graph? I debugged the app and looked into the object itself and couldnt find it.

I know I can use persistence and in MemoryCheckpointer - but I am afraid it will take up too much space in memory (and thus my Azure Functions will be too expensive).

I wan to just access the state vai the object app 😄
How can I do that?

[vbarda]

@Sulomus you can use app.get_state(), see a how-to guide here https://langchain-ai.github.io/langgraph/how-tos/human_in_the_loop/time-travel/

[Sulomus]

I know that MemoryCheckpointer can be used - but as I said I am afraid it will take up too much space in memory.

But even ignoring that fact - I tried it and got Object of type AsyncCallbackManager is not JSON serializable langgraph.

The error is not in my code - it is raised in the app.stream() - this issue is discussed also here in this GitHub discussion.

Is there any other way? Or Memory Checkpointer is the only one?

[nfcampos]

Hi, I'd suggest using stream_mode="values". That way each of the chunks yielded in for loop will be the state at that time, and a new chunk will be emitted any time it changes.