app.py

import os
os.environ.setdefault("PYTORCH_CUDA_ALLOC_CONF", "expandable_segments:True")
os.environ["GRADIO_SSR_MODE"] = "false"   # serve via Python (FastAPI) directly so /ws works
import json
import time
import uuid
import base64
import numpy as np
import spaces
import torch
from gradio import Server
from fastapi import Request
from fastapi.responses import HTMLResponse
from huggingface_hub import hf_hub_download
import asyncio, threading, queue as _q, contextvars, struct
import gradio as gr
from gradio.context import LocalContext
from fastapi import WebSocket, WebSocketDisconnect

from magenta_rt import paths

MAGENTA_HOME = "/data" if os.path.isdir("/data") else "/tmp/magenta"
home = os.path.join(MAGENTA_HOME, "magenta-rt-v2")
os.makedirs(home, exist_ok=True)
for ck in ("mrt2_small.safetensors", "mrt2_base.safetensors"):
    hf_hub_download("google/magenta-realtime-2", f"checkpoints/{ck}", local_dir=home)
paths.set_magenta_home(home)

from magenta_rt.torch import MagentaRT2
from magenta_rt.torch.musiccoca import MusicCoCa

style_model = MusicCoCa(device="cpu")
# Both models fit on ZeroGPU — preload both; the dropdown switches between them.
mrt_small = MagentaRT2(size="mrt2_small", device="cuda", dtype=torch.bfloat16, style_model=style_model)
mrt_base = MagentaRT2(size="mrt2_base", device="cuda", dtype=torch.bfloat16, style_model=style_model)
MODELS = {"mrt2_small": mrt_small, "mrt2_base": mrt_base}
for name, repo in (("mrt2_base", "magenta-torch/magenta-rt-aoti"),
                   ("mrt2_small", "magenta-torch/magenta-rt-aoti-small")):
    try:
        MODELS[name].load_compiled(repo_id=repo)
        print(f"Loaded AOTI for {name} from {repo}")
    except Exception as e:
        print(f"AOTI load failed for {name} ({repo}) -> eager:", e)

SR = 48000
SESSION_DIR = "/tmp/mrt_jam2_sessions"
os.makedirs(SESSION_DIR, exist_ok=True)
_EMB_CACHE = {}


def _embed(label):
    label = (label or "").strip() or "instrumental music"
    if label not in _EMB_CACHE:
        _EMB_CACHE[label] = np.asarray(style_model.embed(label).cpu().numpy(), np.float32)
    return _EMB_CACHE[label]


def _slot(sid):
    return os.path.join(SESSION_DIR, f"{os.path.basename(sid)}.json")


def write_slot(sid, d):
    tmp = _slot(sid) + "." + uuid.uuid4().hex
    with open(tmp, "w") as f:
        json.dump(d, f)
    os.replace(tmp, _slot(sid))


def read_slot(sid):
    try:
        with open(_slot(sid)) as f:
            return json.load(f)
    except Exception:
        return None


def read_client_lead(sid):
    try:
        with open(os.path.join(SESSION_DIR, f"{os.path.basename(sid)}_buf.txt")) as f:
            return float(f.read())
    except Exception:
        return None


def _apply_set(body):                          # build + write the conditioning slot (shared by HTTP /set and the WS)
    sid = body["session_id"]
    prev = read_slot(sid) or {}
    write_slot(sid, {
        "prompts": body.get("prompts") or ["instrumental music"],
        "weights": body.get("weights") or [1.0],
        "audio": body.get("audio") or [],
        "temperature": float(body.get("temperature", 1.1)),
        "top_k": int(body.get("top_k", 50)),
        "cfg_musiccoca": float(body.get("cfg", 1.6)),
        "cfg_notes": float(body.get("cfg_notes", 2.4)),
        "cfg_drums": float(body.get("cfg_drums", 4.0)),
        "model": body.get("model", prev.get("model", "mrt2_base")),
        "buffer": int(body.get("buffer", 0)),
        "notes": list(body.get("notes", [])),
        "unmaskwidth": int(body.get("unmaskwidth", 0)),
        "drumless": bool(body.get("drumless", False)),
        "onsetmode": bool(body.get("onsetmode", False)),
        "reset": int(body.get("reset", 0)),
        "seed": int(body.get("seed", 0)),
        "bank_op": body.get("bank_op", prev.get("bank_op")),
        "ts": time.time(),
    })


def _apply_buffer(sid, lead):
    sid = os.path.basename(str(sid))
    p = os.path.join(SESSION_DIR, f"{sid}_buf.txt")
    with open(p + ".tmp", "w") as f:
        f.write(str(float(lead)))
    os.replace(p + ".tmp", p)


app = Server()


@app.post("/buffer")
async def set_clientbuffer(request: Request):
    body = await request.json()
    _apply_buffer(body["session_id"], body.get("lead", 0))
    return {"ok": True}


@app.post("/set")
async def set_collider(request: Request):
    body = await request.json()
    _apply_set(body)
    return {"ok": True}


@app.post("/audio")
async def set_audio(request: Request):
    """Store an uploaded clip (native-rate mono float32) per (session, slot);
    the GPU stream embeds it with MusicCoCa.embed_audio (resampy -> 16kHz)."""
    body = await request.json()
    sid = os.path.basename(body["session_id"]); slot = int(body.get("slot", 0))
    path = os.path.join(SESSION_DIR, f"{sid}_aud{slot}.bin")
    samples = body.get("samples")
    if not samples:
        try: os.remove(path)
        except OSError: pass
        return {"ok": True}
    raw = base64.b64decode(samples)
    sr = int(body.get("sample_rate", 48000))
    with open(path + ".tmp", "wb") as f:
        f.write(int(sr).to_bytes(4, "little")); f.write(raw)
    os.replace(path + ".tmp", path)
    return {"ok": True}


@app.get("/banks")
async def banks(session_id: str = ""):
    sid = os.path.basename(session_id)
    return {"bankStatus": [os.path.exists(os.path.join(SESSION_DIR, f"{sid}_bank{i}.pt")) for i in range(3)]}


@spaces.GPU(duration=90)
def gpu_stream(session_id):
    """Continuous gen; switches model live when the dropdown changes."""
    from magenta_rt.torch.system import make_sampler, discretize_cfg, _float_to_int16, FRAME_SAMPLES
    if style_model.device != "cuda":
        style_model.to("cuda")
    dev, dt = "cuda", torch.bfloat16
    deadline = time.time() + 8.0
    while read_slot(session_id) is None and time.time() < deadline:
        time.sleep(0.05)
    gen = torch.Generator(device=dev).manual_seed(0)
    try:                                          # one-time GPU warm-up so the first audio frame isn't slow
        style_model.embed("warmup")
        _wd = mrt_base.model.decoder.init_streaming_f(1, dev, dt)
        _wc = mrt_base._conditioning([-1] * mrt_base.num_musiccoca, [-1] * 128, [-1],
                                     [discretize_cfg(1.6, 0.2, 40), discretize_cfg(2.4, 0.2, 40), discretize_cfg(4.0, 1.0, 8)])
        _ws = mrt_base.model.encode(_wc).to(dt)
        for _ in range(2):
            mrt_base.model.decoder.step_f(_wd, _ws, sampler=make_sampler(1.1, 50, gen),
                                          temporal_step=mrt_base._temporal_step, depth_step=mrt_base._depth_step)
        print("[warmup] done", flush=True)
    except Exception as _e:
        print("[warmup]", repr(_e), flush=True)
    notes, drums = [-1] * 128, [-1]
    cur_name = model = dstate = source = None
    decode_state = {}
    emitted_samples = 0
    t0 = time.time()
    buf_log, buf_t = [], t0
    cur_style_sig = cur_note_sig = cur_tokens = None
    prev_active = set()
    cur_reset = cur_seed = 0
    had_onsets = False
    txt_cache, aud_cache = {}, {}
    CHUNK = 3                                   # frames per yield (smaller = finer delivery, lower buffer floor)
    cur_bank_ver = 0
    while time.time() - t0 < 55.0:
        c = read_slot(session_id)
        if c is None:
            time.sleep(0.02)
            continue
        mname = c.get("model", "mrt2_base")
        reset = int(c.get("reset", 0))
        if mname != cur_name or reset != cur_reset:   # model switch / state reset -> re-init
            cur_name, model, cur_reset = mname, MODELS.get(mname, mrt_base), reset
            dstate = model.model.decoder.init_streaming_f(1, dev, dt)
            decode_state = model.init_decode_state()
            emitted_samples, source, prev_active = 0, None, set()
            cur_style_sig = cur_note_sig = cur_tokens = None; had_onsets = False
        seed = int(c.get("seed", 0))
        if seed != cur_seed:
            cur_seed = seed
            gen = torch.Generator(device=dev).manual_seed(seed)
        bop = c.get("bank_op")
        if bop and int(bop.get("ver", 0)) != cur_bank_ver:    # save/recall generation state
            cur_bank_ver = int(bop.get("ver", 0))
            bpath = os.path.join(SESSION_DIR, f"{os.path.basename(session_id)}_bank{int(bop.get('idx', 0))}.pt")
            try:
                if bop.get("action") == "save":
                    torch.save({"dstate": dstate, "decode_state": decode_state, "emitted": emitted_samples}, bpath)
                elif bop.get("action") == "load" and os.path.exists(bpath):
                    d = torch.load(bpath, map_location=dev)
                    dstate, decode_state, emitted_samples = d["dstate"], d["decode_state"], int(d["emitted"])
                    source, cur_note_sig = None, None
            except Exception as e:
                print("[bank] error:", repr(e), flush=True)
        toks = []
        gen_t = time.time()
        for _ in range(CHUNK):                        # per-frame conditioning (native parity: re-derive every 40ms frame, no debounce)
            c = read_slot(session_id) or c
            prompts = c.get("prompts") or ["instrumental music"]
            weights = c.get("weights") or [1.0] * len(prompts)
            aflags = (c.get("audio") or []) + [False] * len(prompts)
            active = set(c.get("notes") or [])
            unmask = int(c.get("unmaskwidth", 0))
            onsetmode = bool(c.get("onsetmode", False))
            drumless = bool(c.get("drumless", False))
            # ---- style tokens on GPU: embed+blend+tokenize, cached until prompts/weights/audio change ----
            style_sig = (tuple(prompts), tuple(round(float(w), 4) for w in weights),
                         tuple(bool(a) for a in aflags[:len(prompts)]))
            if cur_tokens is None or style_sig != cur_style_sig:
                cur_style_sig = style_sig
                emb = torch.zeros(style_model.embedding_dim, device=dev, dtype=torch.float32)
                tot = float(sum(w for w in weights if w > 0)) or 1.0
                for i in range(len(prompts)):
                    w = float(weights[i]) if i < len(weights) else 0.0
                    if w <= 0:
                        continue
                    if i < len(aflags) and aflags[i]:
                        ap = os.path.join(SESSION_DIR, f"{os.path.basename(session_id)}_aud{i}.bin")
                        try: mt = os.path.getmtime(ap)
                        except OSError: continue
                        ce = aud_cache.get(i)
                        if ce is None or ce[0] != mt:
                            data = open(ap, "rb").read()
                            asr = int.from_bytes(data[:4], "little")
                            samp = np.frombuffer(data[4:], dtype=np.float32)
                            ce = (mt, style_model.embed_audio(samp, asr).float()); aud_cache[i] = ce
                        e = ce[1]
                    else:
                        lbl = (prompts[i] or "").strip()
                        if not lbl:
                            continue
                        e = txt_cache.get(lbl)
                        if e is None:
                            e = style_model.embed(lbl).float(); txt_cache[lbl] = e
                    emb = emb + (w / tot) * e
                cur_tokens = style_model.tokenize(emb).tolist()
            # ---- notes + cfg -> re-encode on ANY change every frame (no debounce); onset(2)->sustain(1) via had_onsets ----
            note_sig = (tuple(sorted(active)), unmask, onsetmode, drumless,
                        round(float(c.get("cfg_musiccoca", 1.6)), 3), round(float(c.get("cfg_notes", 2.4)), 3),
                        round(float(c.get("cfg_drums", 4.0)), 3), cur_style_sig)
            if source is None or note_sig != cur_note_sig or had_onsets:
                onsets = active - prev_active
                prev_active = set(active)
                had_onsets = onsetmode and bool(onsets)        # carry one frame so the onset settles to sustain next frame
                cur_note_sig = note_sig
                nvec = []                                      # per-pitch: -1 masked / 0 off / 1 cont / 2 onset / 3 on
                for pitch in range(128):
                    if pitch in active:
                        nvec.append((2 if pitch in onsets else 1) if onsetmode else 3)
                    elif unmask >= 127 or (active and any(abs(pitch - h) <= unmask for h in active)):
                        nvec.append(0)                         # solo (>=127) or within unmask window -> off
                    else:
                        nvec.append(-1)                        # masked (model free)
                drm = [0] if drumless else [-1]                # 0 no-drum / -1 masked
                cfg_notes_v = 7.0 if (unmask >= 127 and not active) else c.get("cfg_notes", 2.4)   # solo + no note held -> ramp cfg_notes to max bin (native JamApp suppresses melody)
                cfgs = [discretize_cfg(c.get("cfg_musiccoca", 1.6), 0.2, 40),
                        discretize_cfg(cfg_notes_v, 0.2, 40),
                        discretize_cfg(c.get("cfg_drums", 4.0), 1.0, 8)]
                cond = model._conditioning((list(cur_tokens) + [-1] * model.num_musiccoca)[:model.num_musiccoca],
                                           nvec, drm, cfgs)
                source = model.model.encode(cond).to(dt)
            sampler = make_sampler(c.get("temperature", 1.1), c.get("top_k", 50), gen)
            toks.append(model.model.decoder.step_f(dstate, source, sampler=sampler,
                        temporal_step=model._temporal_step, depth_step=model._depth_step))
        new_codes = torch.cat(toks, dim=1)
        audio = model.decode_stream(new_codes, decode_state)      # FLOP-optimal stateful streaming decode
        emitted_samples += audio.shape[1]
        frame_ms = (time.time() - gen_t) * 1000.0 / CHUNK     # real per-frame inference time
        if audio.shape[1] > 0:
            ab = _float_to_int16(audio[0].float().cpu().numpy()).astype("<i2").tobytes()
            yield (ab, frame_ms)
        buf = (0.15, 0.3, 0.5)[max(0, min(2, int(c.get("buffer", 0))))]
        ahead = (emitted_samples / SR) - (time.time() - t0)
        if ahead < -0.3:                              # fell behind (cold-start/hiccup) -> resync, no catch-up burst
            t0 = time.time() - (emitted_samples / SR) + buf
            ahead = buf
        buf_log.append(ahead)
        if time.time() - buf_t >= 15.0 and buf_log:
            print(f"[buffer] avg={sum(buf_log)/len(buf_log):.2f}s min={min(buf_log):.2f} "
                  f"max={max(buf_log):.2f} target={buf:.2f}s n={len(buf_log)}", flush=True)
            buf_log, buf_t = [], time.time()
        sleep_for = max(0.0, ahead - buf)
        cl = read_client_lead(session_id)                 # client's real Web-Audio queue (ms)
        if cl is not None and cl - buf * 1000.0 > 200:    # only drain a genuinely-deep queue (target+200ms)
            sleep_for = max(sleep_for, min((cl - buf * 1000.0) / 1000.0 * 0.3, 0.2))  # gentle + capped
        if sleep_for > 0:
            time.sleep(min(sleep_for, 0.5))


_sessions = {}
_slock = threading.Lock()


def _worker(session_id, audio_q, stop_ev):
    try:
        while not stop_ev.is_set():
            try:
                for ab, fm in gpu_stream(session_id):           # ~55s GPU grant; re-grants on loop
                    if stop_ev.is_set():
                        break
                    if audio_q.full():
                        try: audio_q.get_nowait()
                        except _q.Empty: pass
                    try: audio_q.put_nowait((ab, fm))
                    except _q.Full: pass
            except Exception as e:
                if "abort" in str(e).lower() or "duration" in str(e).lower():
                    continue                                    # grant expired -> re-grant
                print("[worker]", repr(e), flush=True); break
    finally:
        stop_ev.set()


@app.api(name="start")
def start(session_id: str = "", request: gr.Request = None) -> str:
    if not session_id:
        return ""
    req = request or LocalContext.request.get(None)      # user's gr.Request -> carries X-IP-Token (ZeroGPU quota)
    with _slock:
        prev = _sessions.pop(session_id, None)
    if prev:
        prev["stop"].set()
    audio_q = _q.Queue(maxsize=48); stop_ev = threading.Event()
    def run():
        if req is not None:
            LocalContext.request.set(req)                # graft user request so worker @spaces.GPU bills the USER
        _worker(session_id, audio_q, stop_ev)
    ctx = contextvars.copy_context()
    t = threading.Thread(target=ctx.run, args=(run,), daemon=True)
    with _slock:
        _sessions[session_id] = {"audio": audio_q, "stop": stop_ev}
    t.start()
    return session_id


@app.websocket("/ws")
async def audio_ws(websocket: WebSocket, session_id: str = ""):
    await websocket.accept()
    sess = _sessions.get(session_id)
    if not sess:
        await websocket.close(code=1008); return
    audio_q, stop_ev = sess["audio"], sess["stop"]
    loop = asyncio.get_event_loop()

    async def send_audio():                       # server -> client: binary audio frames
        try:
            while not stop_ev.is_set():
                try:
                    ab, fm = await loop.run_in_executor(None, lambda: audio_q.get(timeout=0.5))
                except Exception:
                    continue
                await websocket.send_bytes(struct.pack("<f", fm) + ab)
            try: await websocket.send_json({"type": "ended"})   # worker ended (quota/grant)
            except Exception: pass
        finally:
            stop_ev.set()

    async def recv_control():                     # client -> server: low-latency steering (notes/params), no HTTP RTT
        try:
            while not stop_ev.is_set():
                msg = await websocket.receive_json()            # raises WebSocketDisconnect on close
                t = msg.get("type")
                if t == "set":
                    try: _apply_set(msg)
                    except Exception as e: print("[ws set]", repr(e), flush=True)
                elif t == "buffer":
                    try: _apply_buffer(msg.get("session_id", session_id), msg.get("lead", 0))
                    except Exception: pass
        finally:
            stop_ev.set()

    try:
        await asyncio.gather(send_audio(), recv_control(), return_exceptions=True)
    finally:
        stop_ev.set()
        with _slock:
            _sessions.pop(session_id, None)


@app.get("/")
async def index():
    with open(os.path.join(os.path.dirname(os.path.abspath(__file__)), "index.html")) as f:
        return HTMLResponse(f.read())


app.launch(show_error=True, ssr_mode=False)