serve.py

from dotenv import load_dotenv
from fastapi import FastAPI
from langchain_core.output_parsers import StrOutputParser
from langchain_core.prompts import ChatPromptTemplate
from langchain_openai import ChatOpenAI
from langserve import add_routes

load_dotenv()

model = ChatOpenAI(model="gpt-4", temperature=0.1)

system_prompt = "Translate the following into {language}"
prompt_template = ChatPromptTemplate.from_messages(
    [("system", system_prompt), ("user", "{text}")]
)

parser = StrOutputParser()

chain = prompt_template | model | parser

app = FastAPI(
    title="Translator App",
    version="1.0.0",
    description="Translation Chat Bot",
)

add_routes(
    app,
    chain,
    path="/chain",
)

if __name__ == "__main__":
    import uvicorn

    uvicorn.run(app, host="localhost", port=8000)