langgraph/how-tos/streaming-subgraphs/

[giscus[bot]]

langgraph/how-tos/streaming-subgraphs/

Build language agents as graphs

https://langchain-ai.github.io/langgraph/how-tos/streaming-subgraphs/

[manuelImageMakerLatam]

In the latest version (langgraph==0.3.14) the shared key with the state of the parent graph is not being updated.

[simon-lighthouse]

What doesn't seem clear here, is how to stream with a structured output parser on an LLM. When I do so, I get incomplete JSON under the 'content' key. e.g. {"content": "{\n "summary": "• The LIM"} which fails in front end parsing. I have tried to implement a JSONOutputParser but this doesn't impact the LLM run which is streamed, it only runs at the end of the LLM call

[Veshek]

If you're using the langgraph api, then you could setup a websocket and stream the messages using a for loop like this. Not sure how exactly you will handle the streamed messages on the frontend though :

async def stream_response(user_input: str):
"""Stream response from LangGraph agent."""
# Replace this with the URL of your own deployed graph
client = get_client(url=LANGGRAPH_SERVER)
input_message = HumanMessage(content=user_input)
thread = await client.threads.create()
# Start conversation with the initial message
async for event in client.runs.stream(thread["thread_id"],
assistant_id="agent",
input={"messages": [input_message],"user_id":"1"},
stream_mode="messages-tuple"):
if event.event == 'messages':
yield event.data[0]["content"]

[YisusLinkon]

I require to invoke my graph fron a specific node, any of you knows how to do this?
I'm doing this:
invoke = await compiled_graph.ainvoke(agent_state)
I would like to be able to specify the node name to continue an in-progress execution

[XiaoLiuAI]

I tried that as well, but astream does not return any subgraph output as well as llm token (stream does).

[XiaoLiuAI]

The code in tutor works, but when I switch stream to astream, subgraph outputs are gone. How can I stream subgraph output with async?

[crazyyanchao]

Great article. Also, I wanted to ask, graph.get_graph().draw_mermaid doesn't visualize subgraphs very well. Are there any better visualization functions that can be used for this?

[crazyyanchao]

I overlooked using the parameters, but now it works perfectly! set xray=1

print(graph.get_graph(xray=1).draw_mermaid(
    node_colors=NodeStyles(
        default="fill:#ffe6e6,stroke:#ff6666,stroke-width:2px,line-height:1.2",
        first="fill-opacity:0,stroke:#ff6666",
        last="fill:#ff6666,stroke:#b80000")
))