app.py

import os
import torch
from transformers import AutoTokenizer, AutoModelForCausalLM
import gradio as gr
import spaces

huggingface_token = os.getenv("HUGGINGFACE_TOKEN")
if not huggingface_token:
    raise ValueError("HUGGINGFACE_TOKEN environment variable is not set")

model_id = "meta-llama/Llama-Guard-3-8B"
device = "cuda"
dtype = torch.bfloat16

tokenizer = AutoTokenizer.from_pretrained(model_id, token=huggingface_token)


@spaces.GPU
def moderate(chat):
    model = AutoModelForCausalLM.from_pretrained(
        model_id, torch_dtype=dtype, device_map=device, token=huggingface_token
    )
    input_ids = tokenizer.apply_chat_template(chat, return_tensors="pt").to(device)
    output = model.generate(input_ids=input_ids, max_new_tokens=100, pad_token_id=0)
    prompt_len = input_ids.shape[-1]
    return tokenizer.decode(output[0][prompt_len:], skip_special_tokens=True)


def gradio_moderate(user_input, assistant_response):
    chat = [
        {"role": "user", "content": user_input},
    ]
    if assistant_response:
        chat.append({"role": "assistant", "content": assistant_response})
    return moderate(chat)


iface = gr.Interface(
    fn=gradio_moderate,
    inputs=[
        gr.Textbox(lines=3, label="User Input"),
        gr.Textbox(lines=3, label="Assistant Response (optional)"),
    ],
    outputs=gr.Textbox(label="Moderation Result"),
    title="Llama Guard Moderation",
    description="Enter a user input and an optional assistant response to check for content moderation.",
)

if __name__ == "__main__":
    iface.launch()