Guaranteed Availability

from flask import Flask, jsonify
from langfuse import Langfuse
 
# Initialize the Flask app and Langfuse client
app = Flask(__name__)
langfuse = Langfuse()
 
def fetch_prompts_on_startup():
    try:
        # Fetch and cache the production version of the prompt
        langfuse.get_prompt("movie-critic")
    except Exception as e:
        print(f"Failed to fetch prompt on startup: {e}")
        sys.exit(1)  # Exit the application if the prompt is not available
 
# Call the function during application startup
fetch_prompts_on_startup()
 
@app.route('/get-movie-prompt/<movie>', methods=['GET'])
def get_movie_prompt(movie):
    prompt = langfuse.get_prompt("movie-critic")
    compiled_prompt = prompt.compile(criticlevel="expert", movie=movie)
    return jsonify({"prompt": compiled_prompt})
 
if __name__ == '__main__':
    app.run(debug=True)

import express from "express";
import { Langfuse } from "langfuse";
 
// Initialize the Express app and Langfuse client
const app = express();
const langfuse = new Langfuse();
 
async function fetchPromptsOnStartup() {
  try {
    // Fetch and cache the production version of the prompt
    await langfuse.getPrompt("movie-critic");
  } catch (error) {
    console.error("Failed to fetch prompt on startup:", error);
    process.exit(1); // Exit the application if the prompt is not available
  }
}
 
// Call the function during application startup
fetchPromptsOnStartup();
 
app.get("/get-movie-prompt/:movie", async (req, res) => {
  const movie = req.params.movie;
  const prompt = await langfuse.getPrompt("movie-critic");
  const compiledPrompt = prompt.compile({ criticlevel: "expert", movie });
  res.json({ prompt: compiledPrompt });
});
 
app.listen(3000, () => {
  console.log("Server is running on port 3000");
});

from langfuse import Langfuse
langfuse = Langfuse()
 
# Get `text` prompt with fallback
prompt = langfuse.get_prompt(
  "movie-critic",
  fallback="Do you like {{movie}}?"
)
 
# Get `chat` prompt with fallback
chat_prompt = langfuse.get_prompt(
  "movie-critic-chat",
  type="chat",
  fallback=[{"role": "system", "content": "You are an expert on {{movie}}"}]
)
 
# True if the prompt is a fallback
prompt.is_fallback

import { Langfuse } from "langfuse";
const langfuse = new Langfuse();
 
// Get `text` prompt with fallback
const prompt = await langfuse.getPrompt("movie-critic", undefined, {
  fallback: "Do you like {{movie}}?",
});
 
// Get `chat` prompt with fallback
const chatPrompt = await langfuse.getPrompt("movie-critic-chat", undefined, {
  type: "chat",
  fallback: [{ role: "system", content: "You are an expert on {{movie}}" }],
});
 
// True if the prompt is a fallback
prompt.isFallback;