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Langchain

LangChain ↗ is the most popular framework for building AI applications powered by large language models (LLMs).

LangChain publishes multiple Python packages. The following are provided by the Workers runtime:

Get Started

Clone the cloudflare/python-workers-examples repository and run the LangChain example:

Terminal window
git clone https://github.com/cloudflare/python-workers-examples
cd 04-langchain
npx wrangler@latest dev

Example code

from js import Response
from langchain_core.prompts import PromptTemplate
from langchain_openai import OpenAI


async def on_fetch(request, env):
  prompt = PromptTemplate.from_template("Complete the following sentence: I am a {profession} and ")
  llm = OpenAI(api_key=env.API_KEY)
  chain = prompt | llm


  res = await chain.ainvoke({"profession": "electrician"})
  return Response.new(res.split(".")[0].strip())