PythonFunctionTool code how to call my application's code

[qdaoming]

I want to embed langflow (load flow json and run) into my langchain application.
How to let PythonFunctionTool code call application's other module's code?
thx.

[dosubot[bot]]

🤖

Hello @qdaoming! I'm Dosu, an assistant here to help you with your Langflow related questions and issues while we wait for a human maintainer. Just a heads up, I'm a bot, but don't worry, I'm here to make your journey with Langflow as smooth as possible. How can I assist you further with your query?

To embed Langflow into your LangChain application, you can import the necessary modules and use them in your application. Here's a basic example:

from langflow.interface.tools.constants import ALL_TOOLS_NAMES
from langflow.interface.tools.custom import PythonFunctionTool

# Use the tools in your application
tool = ALL_TOOLS_NAMES['PythonFunctionTool']()

To enable PythonFunctionTool to call code from other modules in your application, you can modify the PythonFunctionTool class. This can be done by subclassing PythonFunctionTool and overriding the method that executes the Python function. Here's an example:

class MyPythonFunctionTool(PythonFunctionTool):
    def execute(self, *args, **kwargs):
        # Import the module containing the function you want to call
        my_module = __import__('my_module')

        # Get the function from the module
        my_function = getattr(my_module, 'my_function')

        # Call the function with the provided arguments
        return my_function(*args, **kwargs)

# Now you can use your custom tool in your application
tool = MyPythonFunctionTool()

In this example, my_module is the name of the module containing the function you want to call, and my_function is the name of the function. You need to replace these with the actual names in your application.

Please note that this is a basic example and might need to be adjusted based on the specific requirements of your application. You can refer to the constants.py and custom.py files in the Langflow repository for more details.

Let me know if you need further assistance.

Sources

• src/backend/langflow/interface/tools/constants.py
• src/backend/langflow/custom/customs.py
• src/backend/langflow/interface/tools/custom.py

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[qdaoming]

The answer is not quite related with the question.
Should I put my application directory into langflow environment, to let pythonfunctiontool import my application's module?
That is ugly solution.

[ogabrielluiz]

Hey @qdaoming

We have a setup here: https://github.com/logspace-ai/langflow-extras that you can use as a Repo template.

It sets the variable LANGFLOW_COMPONENTS_PATH and installs this package called langflow_extras which is the folder in the repo.

Another point is, AFAIK, if your module is in the PYTHONPATH variable and your env that has langflow installed has access to that PYTHONPATH, you should be able to import and use it.

The PythonFunctionTool still needs to be a function that calls the module in some way and returns the result as a string.

[qdaoming]

Hi @ogabrielluiz
Thanks for the excellent answer.

[radiantone]

Hi. Does the python code that the python tool invokes run inside the browser? Or back on the server?