langgraph dev complains ModuleNotFoundError: No module named 'langchain.core'

[khteh]

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Example Code

requirements.txt:

langchain-text-splitters
langchain-community
langgraph
langchain-openai
python-dotenv
langchain-google-vertexai
beautifulsoup4
langchain-google-genai
langchain-core

langgraph.json:

{
    "dependencies": [
        "langchain-text-splitters",
        "langchain-community",
        "langgraph",
        "langchain-openai",
        "python-dotenv",
        "langchain-google-vertexai",
        "beautifulsoup4",
        "langchain-google-genai",
        "langchain-core",
        "./my_agent"
    ],
    "graphs": {
        "my_agent": "./my_agent/RAG_Conversation.py:BuildGraph"
    },
    "env": "./.env"
}

BuildGraph():

def BuildGraph(config: RunnableConfig):
    # Compile application and test
    print(f"\n=== {BuildGraph.__name__} ===")
    graph_builder = StateGraph(MessagesState)
    graph_builder.add_node(query_or_respond)
    tools = ToolNode([retrieve]) # Execute the retrieval.
    graph_builder.add_node(tools)
    graph_builder.add_node(generate)
    graph_builder.set_entry_point("query_or_respond")
    graph_builder.add_conditional_edges(
        "query_or_respond",
        tools_condition,
        {END: END, "tools": "tools"},
    )
    graph_builder.add_edge("tools", "generate")
    graph_builder.add_edge("generate", END)
    memory = MemorySaver()
    simple_graph = graph_builder.compile()
    checkpoint_graph = graph_builder.compile(checkpointer=memory)
    return simple_graph,checkpoint_graph

Description

$ langgraph dev
INFO:langgraph_api.cli:

        Welcome to

╦  ┌─┐┌┐┌┌─┐╔═╗┬─┐┌─┐┌─┐┬ ┬
║  ├─┤││││ ┬║ ╦├┬┘├─┤├─┘├─┤
╩═╝┴ ┴┘└┘└─┘╚═╝┴└─┴ ┴┴  ┴ ┴

- 🚀 API: http://127.0.0.1:2024
- 🎨 Studio UI: https://smith.langchain.com/studio/?baseUrl=http://127.0.0.1:2024
- 📚 API Docs: http://127.0.0.1:2024/docs

This in-memory server is designed for development and testing.
For production use, please use LangGraph Cloud.


2025-03-11T10:17:17.472224Z [info     ] Will watch for changes in these directories: ['/usr/src/Python/PyLangChain'] [uvicorn.error] api_variant=local_dev thread_name=MainThread
2025-03-11T10:17:17.472509Z [info     ] Uvicorn running on http://127.0.0.1:2024 (Press CTRL+C to quit) [uvicorn.error] api_variant=local_dev color_message='Uvicorn running on \x1b[1m%s://%s:%d\x1b[0m (Press CTRL+C to quit)' thread_name=MainThread
2025-03-11T10:17:17.472652Z [info     ] Started reloader process [854656] using WatchFiles [uvicorn.error] api_variant=local_dev color_message='Started reloader process [\x1b[36m\x1b[1m854656\x1b[0m] using \x1b[36m\x1b[1mWatchFiles\x1b[0m' thread_name=MainThread
2025-03-11T10:17:17.986520Z [info     ] Using auth of type=noop        [langgraph_api.auth.middleware] api_variant=local_dev thread_name=MainThread
2025-03-11T10:17:17.989120Z [info     ] Started server process [854663] [uvicorn.error] api_variant=local_dev color_message='Started server process [\x1b[36m%d\x1b[0m]' thread_name=MainThread
2025-03-11T10:17:17.989283Z [info     ] Waiting for application startup. [uvicorn.error] api_variant=local_dev thread_name=MainThread
2025-03-11T10:17:19.616989Z [info     ] NumExpr defaulting to 16 threads. [numexpr.utils] api_variant=local_dev thread_name=asyncio_0
2025-03-11T10:17:20.080112Z [warning  ] USER_AGENT environment variable not set, consider setting it to identify your requests. [langchain_community.utils.user_agent] api_variant=local_dev thread_name=asyncio_0
2025-03-11T10:17:20.081646Z [error    ] Traceback (most recent call last):
  File "/home/khteh/.local/lib/python3.12/site-packages/starlette/routing.py", line 692, in lifespan
    async with self.lifespan_context(app) as maybe_state:
               ^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.12/contextlib.py", line 210, in __aenter__
    return await anext(self.gen)
           ^^^^^^^^^^^^^^^^^^^^^
  File "/home/khteh/.local/lib/python3.12/site-packages/langgraph_api/lifespan.py", line 35, in lifespan
    await collect_graphs_from_env(True)
  File "/home/khteh/.local/lib/python3.12/site-packages/langgraph_api/graph.py", line 262, in collect_graphs_from_env
    graph = await run_in_executor(None, _graph_from_spec, spec)
            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/khteh/.local/lib/python3.12/site-packages/langchain_core/runnables/config.py", line 588, in run_in_executor
    return await asyncio.get_running_loop().run_in_executor(
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.12/concurrent/futures/thread.py", line 58, in run
    result = self.fn(*self.args, **self.kwargs)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/khteh/.local/lib/python3.12/site-packages/langchain_core/runnables/config.py", line 579, in wrapper
    return func(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^
  File "/home/khteh/.local/lib/python3.12/site-packages/langgraph_api/graph.py", line 300, in _graph_from_spec
    modspec.loader.exec_module(module)
  File "<frozen importlib._bootstrap_external>", line 995, in exec_module
  File "<frozen importlib._bootstrap>", line 488, in _call_with_frames_removed
  File "/usr/src/Python/PyLangChain/my_agent/RAG_Conversation.py", line 13, in <module>
    from langchain.core.runnables import RunnableConfig
ModuleNotFoundError: No module named 'langchain.core'
Could not import python module for graph:
GraphSpec(id='my_agent', path='./my_agent/RAG_Conversation.py', module=None, variable='BuildGraph', config=None)
This error likely means you haven't installed your project and its dependencies yet. Before running the server, install your project:

If you are using requirements.txt:
python -m pip install -r requirements.txt

If you are using pyproject.toml or setuptools:
python -m pip install -e .

Make sure to run this command from your project's root directory (where your setup.py or pyproject.toml is located)
 [uvicorn.error] api_variant=local_dev thread_name=MainThread
2025-03-11T10:17:20.081864Z [error    ] Application startup failed. Exiting. [uvicorn.error] api_variant=local_dev thread_name=MainThread

python -m pip install -r requirements.txt runs successfully.

System Info

$ python --version
Python 3.12.7

langchain==0.3.20
langchain-community==0.3.19
langchain-core==0.3.43
langchain-google-genai==2.0.11
langchain-google-vertexai==2.0.14
langchain-openai==0.3.8
langchain-text-splitters==0.3.6

$ python -m langchain_core.sys_info

System Information
------------------
> OS:  Linux
> OS Version:  #19-Ubuntu SMP PREEMPT_DYNAMIC Wed Feb 12 21:43:43 UTC 2025
> Python Version:  3.12.7 (main, Feb  4 2025, 14:46:03) [GCC 14.2.0]

Package Information
-------------------
> langchain_core: 0.3.43
> langchain: 0.3.20
> langchain_community: 0.3.19
> langsmith: 0.3.13
> langchain_google_genai: 2.0.11
> langchain_google_vertexai: 2.0.14
> langchain_openai: 0.3.8
> langchain_text_splitters: 0.3.6
> langgraph_api: 0.0.28
> langgraph_cli: 0.1.75
> langgraph_license: Installed. No version info available.
> langgraph_sdk: 0.1.55
> langgraph_storage: Installed. No version info available.

Optional packages not installed
-------------------------------
> langserve

Other Dependencies
------------------
> aiohttp<4.0.0,>=3.8.3: Installed. No version info available.
> anthropic[vertexai]: Installed. No version info available.
> async-timeout<5.0.0,>=4.0.0;: Installed. No version info available.
> click: 8.1.7
> cryptography: 43.0.3
> dataclasses-json<0.7,>=0.5.7: Installed. No version info available.
> filetype: 1.2.0
> google-ai-generativelanguage: 0.6.16
> google-cloud-aiplatform: 1.83.0
> google-cloud-storage: 2.19.0
> httpx: 0.28.1
> httpx-sse: 0.4.0
> httpx-sse<1.0.0,>=0.4.0: Installed. No version info available.
> jsonpatch<2.0,>=1.33: Installed. No version info available.
> jsonschema-rs: 0.20.0
> langchain-anthropic;: Installed. No version info available.
> langchain-aws;: Installed. No version info available.
> langchain-cohere;: Installed. No version info available.
> langchain-community;: Installed. No version info available.
> langchain-core<1.0.0,>=0.3.34: Installed. No version info available.
> langchain-core<1.0.0,>=0.3.41: Installed. No version info available.
> langchain-core<1.0.0,>=0.3.42: Installed. No version info available.
> langchain-deepseek;: Installed. No version info available.
> langchain-fireworks;: Installed. No version info available.
> langchain-google-genai;: Installed. No version info available.
> langchain-google-vertexai;: Installed. No version info available.
> langchain-groq;: Installed. No version info available.
> langchain-huggingface;: Installed. No version info available.
> langchain-mistralai: Installed. No version info available.
> langchain-mistralai;: Installed. No version info available.
> langchain-ollama;: Installed. No version info available.
> langchain-openai;: Installed. No version info available.
> langchain-text-splitters<1.0.0,>=0.3.6: Installed. No version info available.
> langchain-together;: Installed. No version info available.
> langchain-xai;: Installed. No version info available.
> langchain<1.0.0,>=0.3.20: Installed. No version info available.
> langgraph: 0.3.5
> langgraph-checkpoint: 2.0.18
> langsmith-pyo3: Installed. No version info available.
> langsmith<0.4,>=0.1.125: Installed. No version info available.
> langsmith<0.4,>=0.1.17: Installed. No version info available.
> numpy<3,>=1.26.2: Installed. No version info available.
> openai<2.0.0,>=1.58.1: Installed. No version info available.
> orjson: 3.10.15
> packaging: 24.1
> packaging<25,>=23.2: Installed. No version info available.
> pydantic: 2.10.6
> pydantic-settings<3.0.0,>=2.4.0: Installed. No version info available.
> pydantic<3.0.0,>=2.5.2;: Installed. No version info available.
> pydantic<3.0.0,>=2.7.4: Installed. No version info available.
> pydantic<3.0.0,>=2.7.4;: Installed. No version info available.
> pyjwt: 2.10.1
> pytest: 8.3.2
> python-dotenv: 1.0.1
> PyYAML>=5.3: Installed. No version info available.
> requests: 2.32.3
> requests-toolbelt: 1.0.0
> requests<3,>=2: Installed. No version info available.
> rich: 13.9.4
> SQLAlchemy<3,>=1.4: Installed. No version info available.
> sse-starlette: 2.1.3
> starlette: 0.46.1
> structlog: 25.1.0
> tenacity: 9.0.0
> tenacity!=8.4.0,<10,>=8.1.0: Installed. No version info available.
> tenacity!=8.4.0,<10.0.0,>=8.1.0: Installed. No version info available.
> tiktoken<1,>=0.7: Installed. No version info available.
> typing-extensions>=4.7: Installed. No version info available.
> uvicorn: 0.34.0
> watchfiles: 1.0.4
> zstandard: 0.23.0