qwen-image/tour-comfy/edit_api.py

"""
edit_api.py — headless throughput API for Qwen-Image-Edit Rapid-AIO (v23 Q8 GGUF)
running on top of a local ComfyUI server.

Flow per request:  image + prompt  ->  upload to ComfyUI  ->  inject into the
workflow graph  ->  queue  ->  poll until done  ->  return the edited PNG.

Run ComfyUI first (run_comfyui.sh), then this service (start_api.sh).
"""

import io
import os
import json
import time
import uuid
import random
import copy

import requests
from PIL import Image
from fastapi import FastAPI, UploadFile, File, Form, HTTPException
from fastapi.responses import Response

# --- config -----------------------------------------------------------------
COMFY = os.environ.get("COMFY_URL", "http://127.0.0.1:8188").rstrip("/")
WORKFLOW_PATH = os.environ.get(
    "WORKFLOW_PATH",
    os.path.join(os.path.dirname(os.path.abspath(__file__)), "workflow_qwen_edit.json"),
)
# Default target pixel area for the output latent. The MI50 is not fast, so we
# cap at ~1MP by default; raise via MAX_AREA env if you want bigger output.
MAX_AREA = int(os.environ.get("MAX_AREA", str(1024 * 1024)))
GEN_TIMEOUT = int(os.environ.get("GEN_TIMEOUT", "600"))  # seconds per request

# Node ids in workflow_qwen_edit.json (kept stable on purpose).
NODE_LOADIMAGE = "4"
NODE_POSITIVE = "5"
NODE_LATENT = "7"
NODE_KSAMPLER = "8"
NODE_SAVE = "10"

MAX_SEED = 2**32 - 1

with open(WORKFLOW_PATH, "r", encoding="utf-8") as f:
    BASE_WORKFLOW = json.load(f)

app = FastAPI(title="Qwen-Image-Edit Rapid-AIO API", version="1.0")


# --- helpers ----------------------------------------------------------------
def _round16(x: int) -> int:
    return max(16, int(round(x / 16.0)) * 16)


def _target_size(w: int, h: int, max_area: int) -> tuple[int, int]:
    """Scale (w, h) to ~max_area preserving aspect, rounded to /16."""
    scale = (max_area / float(w * h)) ** 0.5
    return _round16(w * scale), _round16(h * scale)


def _comfy_upload(img_bytes: bytes, filename: str) -> str:
    """Upload an image to ComfyUI's input dir; return the stored name."""
    r = requests.post(
        f"{COMFY}/upload/image",
        files={"image": (filename, img_bytes, "image/png")},
        data={"overwrite": "true", "type": "input"},
        timeout=60,
    )
    r.raise_for_status()
    j = r.json()
    name = j["name"]
    sub = j.get("subfolder", "")
    return f"{sub}/{name}" if sub else name


def _comfy_queue(graph: dict, client_id: str) -> str:
    r = requests.post(
        f"{COMFY}/prompt",
        json={"prompt": graph, "client_id": client_id},
        timeout=60,
    )
    if r.status_code != 200:
        raise HTTPException(502, f"ComfyUI rejected workflow: {r.text}")
    return r.json()["prompt_id"]


def _comfy_wait(prompt_id: str, deadline: float) -> dict:
    """Poll /history until the prompt finishes; return its outputs dict."""
    while time.time() < deadline:
        r = requests.get(f"{COMFY}/history/{prompt_id}", timeout=30)
        if r.status_code == 200:
            hist = r.json()
            if prompt_id in hist:
                entry = hist[prompt_id]
                status = entry.get("status", {})
                if status.get("status_str") == "error":
                    raise HTTPException(500, f"ComfyUI execution error: {json.dumps(status)}")
                outputs = entry.get("outputs", {})
                if outputs:
                    return outputs
        time.sleep(0.5)
    raise HTTPException(504, f"Generation timed out after {GEN_TIMEOUT}s")


def _comfy_fetch_image(outputs: dict) -> bytes:
    node_out = outputs.get(NODE_SAVE) or next(
        (v for v in outputs.values() if "images" in v), None
    )
    if not node_out or not node_out.get("images"):
        raise HTTPException(500, "No output image produced")
    img = node_out["images"][0]
    r = requests.get(
        f"{COMFY}/view",
        params={
            "filename": img["filename"],
            "subfolder": img.get("subfolder", ""),
            "type": img.get("type", "output"),
        },
        timeout=60,
    )
    r.raise_for_status()
    return r.content


# --- routes -----------------------------------------------------------------
@app.get("/health")
def health():
    try:
        requests.get(f"{COMFY}/system_stats", timeout=5).raise_for_status()
        return {"status": "ok", "comfy": COMFY}
    except Exception as e:
        raise HTTPException(503, f"ComfyUI unreachable at {COMFY}: {e}")


@app.post("/edit")
async def edit(
    image: UploadFile = File(...),
    prompt: str = Form(...),
    seed: int = Form(-1),
    steps: int = Form(4),
    cfg: float = Form(1.0),
    sampler_name: str = Form("euler_ancestral"),
    scheduler: str = Form("beta"),
    max_area: int = Form(0),
):
    raw = await image.read()
    try:
        pil = Image.open(io.BytesIO(raw)).convert("RGB")
    except Exception as e:
        raise HTTPException(400, f"Invalid image: {e}")

    area = max_area if max_area > 0 else MAX_AREA
    w, h = _target_size(pil.width, pil.height, area)

    buf = io.BytesIO()
    pil.save(buf, format="PNG")
    stored = _comfy_upload(buf.getvalue(), f"in_{uuid.uuid4().hex[:8]}.png")

    if seed is None or seed < 0:
        seed = random.randint(0, MAX_SEED)

    graph = copy.deepcopy(BASE_WORKFLOW)
    graph[NODE_LOADIMAGE]["inputs"]["image"] = stored
    graph[NODE_POSITIVE]["inputs"]["prompt"] = prompt
    graph[NODE_LATENT]["inputs"]["width"] = w
    graph[NODE_LATENT]["inputs"]["height"] = h
    ks = graph[NODE_KSAMPLER]["inputs"]
    ks.update(seed=seed, steps=steps, cfg=cfg,
              sampler_name=sampler_name, scheduler=scheduler)

    client_id = uuid.uuid4().hex
    prompt_id = _comfy_queue(graph, client_id)
    outputs = _comfy_wait(prompt_id, time.time() + GEN_TIMEOUT)
    png = _comfy_fetch_image(outputs)

    return Response(
        content=png,
        media_type="image/png",
        headers={
            "X-Seed": str(seed),
            "X-Width": str(w),
            "X-Height": str(h),
            "X-Prompt-Id": prompt_id,
        },
    )


if __name__ == "__main__":
    import uvicorn
    uvicorn.run(app, host=os.environ.get("HOST", "0.0.0.0"),
                port=int(os.environ.get("PORT", "8500")))