app.py

import os
import re
import torch
from threading import Thread
from typing import Iterator
from mongoengine import connect, Document, StringField, SequenceField
import gradio as gr
import spaces
from transformers import AutoModelForCausalLM, AutoTokenizer, BitsAndBytesConfig, TextIteratorStreamer
from peft import PeftModel

# Constants
MAX_MAX_NEW_TOKENS = 2048
DEFAULT_MAX_NEW_TOKENS = 1024
MAX_INPUT_TOKEN_LENGTH = int(os.getenv("MAX_INPUT_TOKEN_LENGTH", "4096"))

LICENSE = """
---
As a derivative work of [Llama-2-7b-hf](https://huggingface.co/meta-llama/Llama-2-7b-hf) by Meta,
this demo is governed by the original [license](https://huggingface.co/spaces/huggingface-projects/llama-2-7b-chat/blob/main/LICENSE.txt) and [acceptable use policy](https://huggingface.co/spaces/huggingface-projects/llama-2-7b-chat/blob/main/USE_POLICY.md).
"""

# GPU Check and add CPU warning
if not torch.cuda.is_available():
    DESCRIPTION += "\n<p>Running on CPU 🥶 This demo does not work on CPU.</p>"

if torch.cuda.is_available():

    # Model and Tokenizer Configuration
    model_id = "meta-llama/Llama-2-7b-chat-hf"
    bnb_config = BitsAndBytesConfig(
        load_in_4bit=True,
        bnb_4bit_use_double_quant=False,
        bnb_4bit_quant_type="nf4",
        bnb_4bit_compute_dtype=torch.bfloat16
    )
    base_model = AutoModelForCausalLM.from_pretrained(model_id, device_map="auto", quantization_config=bnb_config)
    model = PeftModel.from_pretrained(base_model, "ranamhamoud/storytell")
    tokenizer = AutoTokenizer.from_pretrained(model_id)
    tokenizer.pad_token = tokenizer.eos_token

# # MongoDB Connection
# PASSWORD = os.environ.get("MONGO_PASS")
# connect(host=f"mongodb+srv://ranamhammoud11:{PASSWORD}@stories.zf5v52a.mongodb.net/")

# # MongoDB Document
# class Story(Document):
#     message = StringField()
#     content = StringField()
#     story_id = SequenceField(primary_key=True)

# Utility function for prompts
def make_prompt(entry):
    return  f"### Human: When asked to explain use a story.Don't repeat the assesments, limit to 500 words.However keep context in mind if edits to the content is required. {entry} ### Assistant:"
    # f"TELL A STORY, RELATE TO COMPUTER SCIENCE, INCLUDE ASSESMENTS. MAKE IT REALISTIC AND AROUND 800 WORDS, END THE STORY WITH "THE END.": {entry}"

def process_text(text):
    # First, handle the specific case for [answer:]
    # This replaces [answer:] with "Answer:" and keeps the content after it on the same line.
    text = re.sub(r'\[answer:\]\s*', 'Answer: ', text)
    
    # Now, remove all other content within brackets.
    # This regex looks for square brackets and any content inside them, excluding those that start with "Answer: " already modified.
    text = re.sub(r'\[.*?\](?<!Answer: )', '', text)
    
    return text
custom_css = """
body, input, button, textarea, label {
    font-family: Arial, sans-serif;
    font-size: 24px;
}
.gr-chat-interface .gr-chat-message-container {
    font-size: 14px;
}
.gr-button {
    font-size: 14px;
    padding: 12px 24px;
}
.gr-input {
    font-size: 14px;
}
"""

# Gradio Function
@spaces.GPU
def generate(
    message: str,
    chat_history: list[tuple[str, str]],
    max_new_tokens: int = DEFAULT_MAX_NEW_TOKENS,
    temperature: float = 0.6,
    top_p: float = 0.7,
    top_k: int = 20,
    repetition_penalty: float = 1.0,
) -> Iterator[str]:
    conversation = []
    for user, assistant in chat_history:
        conversation.extend([{"role": "user", "content": user}, {"role": "assistant", "content": assistant}])
    conversation.append({"role": "user", "content": make_prompt(message)})
    enc = tokenizer(make_prompt(message), return_tensors="pt", padding=True, truncation=True)
    input_ids = enc.input_ids.to(model.device)
    if input_ids.shape[1] > MAX_INPUT_TOKEN_LENGTH:
        input_ids = input_ids[:, -MAX_INPUT_TOKEN_LENGTH:]
        gr.Warning(f"Trimmed input from conversation as it was longer than {MAX_INPUT_TOKEN_LENGTH} tokens.")
    
    streamer = TextIteratorStreamer(tokenizer, timeout=10.0, skip_prompt=True, skip_special_tokens=False)
    generate_kwargs = dict(
        {"input_ids": input_ids},
        streamer=streamer,
        max_new_tokens=max_new_tokens,
        do_sample=True,
        top_p=top_p,
        top_k=top_k,
        temperature=temperature,
        num_beams=1,
        repetition_penalty=repetition_penalty,
    )
    t = Thread(target=model.generate, kwargs=generate_kwargs)
    t.start()

    outputs = []
    for text in streamer:
        processed_text = process_text(text)
        outputs.append(processed_text)
        output = "".join(outputs)
        yield output

    # final_story = "".join(outputs)
    # try:
    #     saved_story = Story(message=message, content=final_story).save()
    #     yield f"{final_story}\n\n Story saved with ID: {saved_story.story_id}"
    # except Exception as e:
    #     yield f"Failed to save story: {str(e)}"

# Gradio Interface Setup
chat_interface = gr.ChatInterface(
    fn=generate,
    fill_height=True,
    stop_btn=None,
    examples=[
        ["Can you explain briefly to me what is the Python programming language?"],
        ["Could you please provide an explanation about the concept of recursion?"],
        ["Could you explain what a URL is?"]
    ],
    theme='shivi/calm_seafoam'
)

# Gradio Web Interface
with gr.Blocks(css=custom_css,theme='shivi/calm_seafoam',fill_height=True) as demo:
    chat_interface.render()
    # gr.Markdown(LICENSE)


# Main Execution
if __name__ == "__main__":
    demo.queue(max_size=20)
    demo.launch(share=True)