示例：在 Langchain（Python）中使用 Litefuse Prompt 管理

%pip install langfuse langchain langchain-openai --upgrade

import os
 
# Get keys for your project from the project settings page: https://litefuse.cloud
os.environ["LANGFUSE_PUBLIC_KEY"] = "pk-lf-..." 
os.environ["LANGFUSE_SECRET_KEY"] = "sk-lf-..." 
os.environ["LANGFUSE_BASE_URL"] = "https://litefuse.cloud"
 
# Your openai key
os.environ["OPENAI_API_KEY"] = "sk-proj-..."

from langfuse import get_client
from langfuse.langchain import CallbackHandler
 
# Initialize Langfuse client (prompt management)
langfuse = get_client()
 
# Initialize Langfuse CallbackHandler for Langchain (tracing)
langfuse_callback_handler = CallbackHandler()

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-4o",
        "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}")

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)