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:

• langchain ↗ (version 0.1.8)
• langchain-core ↗ (version 0.1.25)
• langchain-openai ↗ (version 0.0.6)

Get Started

Python Workers are in beta. Packages do not run in production.

Currently, you can only deploy Python Workers that use the standard library. Packages cannot be deployed and will only work in local development for the time being.

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

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())

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