app.py

import numpy as np
import PIL.Image
import torch
from diffusers import StableCascadeDecoderPipeline, StableCascadePriorPipeline
import uvicorn
from fastapi.middleware.cors import CORSMiddleware
from fastapi.responses import RedirectResponse, StreamingResponse
import io
import os
from pathlib import Path
from db import Database
import uuid
import logging
from fastapi import FastAPI, Request, HTTPException
from asyncio import Lock


logging.basicConfig(level=os.environ.get("LOGLEVEL", "INFO"))

MAX_SEED = np.iinfo(np.int32).max
USE_TORCH_COMPILE = os.environ.get("USE_TORCH_COMPILE", "0") == "1"
SPACE_ID = os.environ.get("SPACE_ID", "")
DEV = os.environ.get("DEV", "0") == "1"
os.environ["TOKENIZERS_PARALLELISM"] = "false"

DB_PATH = Path("/data/cache") if SPACE_ID else Path("./cache")
IMGS_PATH = DB_PATH / "imgs"
DB_PATH.mkdir(exist_ok=True, parents=True)
IMGS_PATH.mkdir(exist_ok=True, parents=True)

database = Database(DB_PATH)
generate_lock = Lock()

dtype = torch.bfloat16
device = torch.device("cuda:0" if torch.cuda.is_available() else "cpu")
if torch.cuda.is_available():
    prior_pipeline = StableCascadePriorPipeline.from_pretrained(
        "stabilityai/stable-cascade-prior", variant="bf16", torch_dtype=torch.bfloat16
    ).to(device)
    decoder_pipeline = StableCascadeDecoderPipeline.from_pretrained(
        "stabilityai/stable-cascade", variant="bf16", torch_dtype=torch.bfloat16
    ).to(device)

    if USE_TORCH_COMPILE:
        prior_pipeline.prior = torch.compile(
            prior_pipeline.prior, mode="reduce-overhead", fullgraph=True
        )
        decoder_pipeline.decoder = torch.compile(
            decoder_pipeline.decoder, mode="max-autotune", fullgraph=True
        )


def generate(
    prompt: str,
    negative_prompt: str = "",
    seed: int = 0,
    width: int = 1024,
    height: int = 1024,
    prior_num_inference_steps: int = 20,
    prior_guidance_scale: float = 4.0,
    decoder_num_inference_steps: int = 10,
    decoder_guidance_scale: float = 0.0,
    num_images_per_prompt: int = 1,
) -> PIL.Image.Image:
    generator = torch.Generator().manual_seed(seed)
    prior_output = prior_pipeline(
        prompt=prompt,
        height=height,
        width=width,
        num_inference_steps=prior_num_inference_steps,
        negative_prompt=negative_prompt,
        guidance_scale=prior_guidance_scale,
        num_images_per_prompt=num_images_per_prompt,
        generator=generator,
    )
    decoder_output = decoder_pipeline(
        image_embeddings=prior_output.image_embeddings,
        prompt=prompt,
        num_inference_steps=decoder_num_inference_steps,
        # timesteps=decoder_timesteps,
        guidance_scale=decoder_guidance_scale,
        negative_prompt=negative_prompt,
        generator=generator,
        output_type="pil",
    ).images

    return decoder_output[0]


app = FastAPI()
origins = [
    "https://huggingface.co",
    "http://huggingface.co",
    "https://huggingface.co/",
    "http://huggingface.co/",
]

app.add_middleware(
    CORSMiddleware,
    allow_origins=origins,
    allow_credentials=True,
    allow_methods=["*"],
    allow_headers=["*"],
)


@app.middleware("http")
async def validate_origin(request: Request, call_next):
    if DEV:
        return await call_next(request)
    if request.headers.get("referer") not in origins:
        raise HTTPException(status_code=403, detail="Forbidden")
    return await call_next(request)


@app.get("/image")
async def generate_image(
    prompt: str, negative_prompt: str = "", seed: int = 2134213213
):
    cached_img = database.check(prompt, negative_prompt, seed)
    if cached_img:
        logging.info(f"Image found in cache: {cached_img[0]}")
        return StreamingResponse(open(cached_img[0], "rb"), media_type="image/jpeg")

    logging.info(f"Image not found in cache, generating new image")
    async with generate_lock:
        pil_image = generate(prompt, negative_prompt, seed)
        img_id = str(uuid.uuid4())
        img_path = IMGS_PATH / f"{img_id}.jpg"
        pil_image.save(img_path)
        img_io = io.BytesIO()
        pil_image.save(img_io, "JPEG")
        img_io.seek(0)
        database.insert(prompt, negative_prompt, str(img_path), seed)

    return StreamingResponse(img_io, media_type="image/jpeg")


@app.get("/")
async def main():
    # redirect to https://huggingface.co/spaces/multimodalart/stable-cascade
    return RedirectResponse(
        "https://multimodalart-stable-cascade.hf.space/?__theme=system"
    )


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