app.py

import os
import logging
import time
from io import BytesIO

from fastapi import FastAPI, HTTPException, Response, Request
from fastapi.responses import StreamingResponse
from pydantic import BaseModel
from transformers import (
    AutoConfig,
    AutoModelForCausalLM,
    AutoTokenizer,
    pipeline,
    GenerationConfig
)
import boto3
from huggingface_hub import hf_hub_download
import soundfile as sf
import numpy as np
import torch
import uvicorn
from tqdm import tqdm

logging.basicConfig(level=logging.INFO, format="%(asctime)s - %(levelname)s - %(message)s")

AWS_ACCESS_KEY_ID = os.getenv("AWS_ACCESS_KEY_ID")
AWS_SECRET_ACCESS_KEY = os.getenv("AWS_SECRET_ACCESS_KEY")
AWS_REGION = os.getenv("AWS_REGION")
S3_BUCKET_NAME = os.getenv("S3_BUCKET_NAME")
HUGGINGFACE_HUB_TOKEN = os.getenv("HUGGINGFACE_HUB_TOKEN")

class GenerateRequest(BaseModel):
    model_name: str
    input_text: str
    task_type: str
    temperature: float = 1.0
    max_new_tokens: int = 200
    stream: bool = False
    top_p: float = 1.0
    top_k: int = 50
    repetition_penalty: float = 1.0
    num_return_sequences: int = 1
    do_sample: bool = True
    chunk_delay: float = 0.0

class S3ModelLoader:
    def __init__(self, bucket_name, s3_client):
        self.bucket_name = bucket_name
        self.s3_client = s3_client

    def _get_s3_uri(self, model_name):
        return f"s3://{self.bucket_name}/{model_name.replace('/', '-')}"

    async def load_model_and_tokenizer(self, model_name):
        s3_uri = self._get_s3_uri(model_name)
        try:
            logging.info(f"Trying to load {model_name} from S3...")
            config = AutoConfig.from_pretrained(s3_uri)
            model = AutoModelForCausalLM.from_pretrained(s3_uri, config=config)
            tokenizer = AutoTokenizer.from_pretrained(s3_uri)
            logging.info(f"Loaded {model_name} from S3 successfully.")
            return model, tokenizer
        except EnvironmentError:
            logging.info(f"Model {model_name} not found in S3. Downloading...")
            try:
                with tqdm(unit="B", unit_scale=True, desc=f"Downloading {model_name}", disable=False) as t:
                    model = AutoModelForCausalLM.from_pretrained(model_name, token=HUGGINGFACE_HUB_TOKEN, _tqdm=t)
                    tokenizer = AutoTokenizer.from_pretrained(model_name, token=HUGGINGFACE_HUB_TOKEN)
                logging.info(f"Downloaded {model_name} successfully.")
                logging.info(f"Saving {model_name} to S3...")
                model.save_pretrained(s3_uri)
                tokenizer.save_pretrained(s3_uri)
                logging.info(f"Saved {model_name} to S3 successfully.")
                return model, tokenizer
            except Exception as e:
                logging.error(f"Error downloading/uploading model: {e}")
                raise HTTPException(status_code=500, detail=f"Error loading model: {e}")

app = FastAPI()

s3_client = boto3.client('s3', aws_access_key_id=AWS_ACCESS_KEY_ID, aws_secret_access_key=AWS_SECRET_ACCESS_KEY, region_name=AWS_REGION)
model_loader = S3ModelLoader(S3_BUCKET_NAME, s3_client)

@app.post("/generate")
async def generate(request: Request, body: GenerateRequest):
    try:
        model, tokenizer = await model_loader.load_model_and_tokenizer(body.model_name)
        device = "cuda" if torch.cuda.is_available() else "cpu"
        model.to(device)

        if body.task_type == "text-to-text":
            generation_config = GenerationConfig(
                temperature=body.temperature,
                max_new_tokens=body.max_new_tokens,
                top_p=body.top_p,
                top_k=body.top_k,
                repetition_penalty=body.repetition_penalty,
                do_sample=body.do_sample,
                num_return_sequences=body.num_return_sequences
            )

            async def stream_text():
                input_text = body.input_text
                generated_text = ""
                max_length = model.config.max_position_embeddings

                while True:
                    encoded_input = tokenizer(input_text, return_tensors="pt", truncation=True, max_length=max_length).to(device)
                    input_length = encoded_input["input_ids"].shape[1]
                    remaining_tokens = max_length - input_length

                    if remaining_tokens <= 0:
                        break

                    generation_config.max_new_tokens = min(remaining_tokens, body.max_new_tokens)

                    output = model.generate(**encoded_input, generation_config=generation_config)
                    chunk = tokenizer.decode(output[0], skip_special_tokens=True)
                    generated_text += chunk
                    yield chunk
                    time.sleep(body.chunk_delay)
                    input_text = generated_text

            if body.stream:
                return StreamingResponse(stream_text(), media_type="text/plain")
            else:
                generated_text = ""
                async for chunk in stream_text():
                    generated_text += chunk
                return {"result": generated_text}

        elif body.task_type == "text-to-image":
            generator = pipeline("text-to-image", model=model, tokenizer=tokenizer, device=device)
            image = generator(body.input_text)[0]
            image_bytes = image.tobytes()
            return Response(content=image_bytes, media_type="image/png")

        elif body.task_type == "text-to-speech":
            generator = pipeline("text-to-speech", model=model, tokenizer=tokenizer, device=device)
            audio = generator(body.input_text)
            audio_bytesio = BytesIO()
            sf.write(audio_bytesio, audio["sampling_rate"], np.int16(audio["audio"]))
            audio_bytes = audio_bytesio.getvalue()
            return Response(content=audio_bytes, media_type="audio/wav")

        elif body.task_type == "text-to-audio":
            generator = pipeline("text-to-audio", model=model, tokenizer=tokenizer, device=device)
            audio = generator(body.input_text)
            audio_bytesio = BytesIO()
            sf.write(audio_bytesio, audio["sampling_rate"], np.int16(audio["audio"]))
            audio_bytes = audio_bytesio.getvalue()
            return Response(content=audio_bytes, media_type="audio/wav")
        
        elif body.task_type == "text-to-video":
            try:
                generator = pipeline("text-to-video", model=model, tokenizer=tokenizer, device=device)
                video = generator(body.input_text)
                return Response(content=video, media_type="video/mp4")
            except Exception as e:
                raise HTTPException(status_code=500, detail=f"Error in text-to-video generation: {e}")

        else:
            raise HTTPException(status_code=400, detail="Unsupported task type")

    except HTTPException as e:
        raise e
    except Exception as e:
        raise HTTPException(status_code=500, detail=str(e))


if __name__ == "__main__":
    uvicorn.run(app, host="0.0.0.0", port=7860)