Example: Langfuse Prompt Management with Langchain (Python)

%pip install langfuse langchain langchain-openai --upgrade

import os
 
# get keys for your project from https://cloud.langfuse.com
os.environ["LANGFUSE_PUBLIC_KEY"] = ""
os.environ["LANGFUSE_SECRET_KEY"] = ""
os.environ["LANGFUSE_HOST"] = "https://cloud.langfuse.com"
 
# your openai key
os.environ["OPENAI_API_KEY"] = ""

from langfuse import Langfuse
from langfuse.callback import CallbackHandler
 
# Initialize Langfuse client (prompt management)
langfuse = Langfuse()
 
# Initialize Langfuse CallbackHandler for Langchain (tracing)
langfuse_callback_handler = CallbackHandler()
 
# Optional, verify that Langfuse is configured correctly
assert langfuse.auth_check()
assert langfuse_callback_handler.auth_check()

langfuse.create_prompt(
    name="event-planner",
    prompt=
    "Plan an event titled {{Event Name}}. The event will be about: {{Event Description}}. "
    "The event will be held in {{Location}} on {{Date}}. "
    "Consider the following factors: audience, budget, venue, catering options, and entertainment. "
    "Provide a detailed plan including potential vendors and logistics.",
    config={
        "model":"gpt-3.5-turbo-1106",
        "temperature": 0,
    },
    labels=["production"]
);

# Get current production version of prompt
langfuse_prompt = langfuse.get_prompt("event-planner")

print(langfuse_prompt.prompt)

Plan an event titled {{Event Name}}. The event will be about: {{Event Description}}. The event will be held in {{Location}} on {{Date}}. Consider the following factors: audience, budget, venue, catering options, and entertainment. Provide a detailed plan including potential vendors and logistics.

from langchain_core.prompts import ChatPromptTemplate
 
langchain_prompt = ChatPromptTemplate.from_template(
        langfuse_prompt.get_langchain_prompt(),
        metadata={"langfuse_prompt": langfuse_prompt},
    )

model = langfuse_prompt.config["model"]
temperature = str(langfuse_prompt.config["temperature"])
print(f"Prompt model configurations\nModel: {model}\nTemperature: {temperature}")

Prompt model configurations
Model: gpt-3.5-turbo-1106
Temperature: 0

from langchain_openai import ChatOpenAI
 
model = ChatOpenAI(model=model, temperature=temperature)
 
chain = langchain_prompt | model

example_input = {
    "Event Name": "Wedding",
    "Event Description": "The wedding of Julia and Alex, a charming couple who share a love for art and nature. This special day will celebrate their journey together with a blend of traditional and contemporary elements, reflecting their unique personalities.",
    "Location": "Central Park, New York City",
    "Date": "June 5, 2024"
}

# we pass the callback handler to the chain to trace the run in Langfuse
response = chain.invoke(input=example_input,config={"callbacks":[langfuse_callback_handler]})
 
print(response.content)

Event Title: Julia and Alex's Artful Nature Wedding

Audience: Family, friends, and loved ones of Julia and Alex, as well as art and nature enthusiasts.

Budget: $30,000

Venue: Central Park, New York City

Catering Options: 
- Organic and locally sourced menu options
- Vegetarian and vegan options
- Artfully presented dishes
- Champagne toast and signature cocktails

Entertainment:
- Live acoustic music during the ceremony
- DJ for the reception
- Interactive art stations for guests to create their own masterpieces
- Nature-inspired photo booth

Logistics:
- Ceremony and reception to be held in a secluded area of Central Park, surrounded by lush greenery and blooming flowers
- Tents and seating to be set up for guests
- Art installations and sculptures to be placed around the venue
- Transportation for guests to and from the park
- Permits and permissions for the event in Central Park

Potential Vendors:
- Catering: Farm-to-table catering company
- Music: Local acoustic musician and DJ
- Art installations: Local artists and galleries
- Photography: Nature and art-focused photographer
- Transportation: Eco-friendly shuttle service

Overall, the wedding will be a beautiful blend of art and nature, with a focus on sustainability and creativity. The event will showcase the couple's love for each other and their shared passions, creating a memorable and unique experience for all in attendance.