app.py

from fastapi import FastAPI
from langchain.prompts import ChatPromptTemplate
from langchain.chat_models import ChatOpenAI
from langserve import add_routes
import uvicorn
import os 

os.environ['OPENAI_API_KEY']=os.getenv("OPENAI_API_KEY")
app= FastAPI(
    title = "Langchain Server",
    version ="1.0",
    description="A Simple API Server"
)


add_routes(
    app,
    ChatOpenAI(),
    path="/openai"
)


model= ChatOpenAI
prompt=ChatPromptTemplate.from_template("Provide me an essay about {topic}")
prompt1=ChatPromptTemplate.from_template("Provide me an poem about {topic}")

add_routes(
    app,
    prompt|model,
    path="/essay"
)

add_routes(
    app,
    prompt1|model,
    path="/poem"
)

if __name__ = __main__:
uvicorn.run(app,host="localhost",port=8000)