feat(music-lab): 배치 음악 생성 endpoint + 자동 compile·video 파이프라인 오케스트레이터

- batch_generator.py: 장르별 N트랙 순차 Suno 생성 → 자동 compile → 자동 video pipeline
- main.py: POST/GET /api/music/generate-batch, GET /api/music/generate-batch/{id} 추가
- tests: 10개 endpoint 테스트 (검증·필터·404)

music-lab/app/batch_generator.py

@@ -0,0 +1,148 @@
+"""배치 음악 생성 + 자동 컴파일·영상 파이프라인."""
+import asyncio
+import logging
+import uuid
+
+from . import db
+from .random_pools import randomize
+
+logger = logging.getLogger("music-lab.batch")
+
+POLL_INTERVAL_S = 5
+TRACK_GEN_TIMEOUT_S = 240
+
+
+async def run_batch(batch_id: int) -> None:
+    """1) genre로 N트랙 순차 Suno 생성
+       2) 모두 완료 후 compile_job 자동 생성·실행
+       3) compile 완료 후 영상 파이프라인 시작 (cover step)
+    """
+    job = db.get_batch_job(batch_id)
+    if not job:
+        return
+    genre = job["genre"]
+    count = job["count"]
+    duration = job["target_duration_sec"]
+    auto_pipe = bool(job["auto_pipeline"])
+
+    db.update_batch_job(batch_id, status="generating")
+
+    track_ids: list[int] = []
+    for i in range(1, count + 1):
+        title = f"{genre.title()} Mix Track {i}"
+        params = randomize(genre)
+        db.update_batch_job(batch_id,
+                            current_track_index=i,
+                            current_track_status="generating")
+
+        track_id = await _generate_one_track(
+            title=title, genre=genre,
+            duration_sec=duration, params=params,
+        )
+        if track_id:
+            track_ids.append(track_id)
+            db.append_batch_track(batch_id, track_id)
+            db.update_batch_job(batch_id, current_track_status="succeeded")
+        else:
+            db.update_batch_job(batch_id, current_track_status="failed")
+            logger.warning("배치 %d 트랙 %d 실패 — 계속 진행", batch_id, i)
+
+    if not track_ids:
+        db.update_batch_job(batch_id, status="failed",
+                            error="모든 트랙 생성 실패")
+        return
+
+    db.update_batch_job(batch_id, status="generated")
+
+    if not auto_pipe:
+        return
+
+    # 자동 컴파일
+    db.update_batch_job(batch_id, status="compiling")
+    try:
+        compile_id = db.create_compile_job(
+            title=f"{genre.title()} Mix",
+            track_ids=track_ids,
+            crossfade_sec=3.0,
+        )
+        db.update_batch_job(batch_id, compile_job_id=compile_id)
+    except Exception as e:
+        logger.exception("compile create failed")
+        db.update_batch_job(batch_id, status="failed", error=f"compile create: {e}")
+        return
+
+    from . import compiler
+    try:
+        await asyncio.to_thread(compiler.run_compile, compile_id)
+    except Exception as e:
+        logger.exception("compile run failed")
+        db.update_batch_job(batch_id, status="failed", error=f"compile run: {e}")
+        return
+
+    job_after = db.get_compile_job(compile_id)
+    status_after = job_after.get("status") if job_after else None
+    if status_after not in ("done", "succeeded"):
+        db.update_batch_job(
+            batch_id, status="failed",
+            error=f"compile not done (status={status_after})"
+        )
+        return
+
+    # 자동 영상 파이프라인
+    try:
+        pipeline_id = db.create_pipeline(compile_job_id=compile_id)
+        db.update_batch_job(batch_id, pipeline_id=pipeline_id, status="piped")
+
+        from .pipeline import orchestrator
+        await orchestrator.run_step(pipeline_id, "cover")
+    except Exception as e:
+        logger.exception("pipeline launch failed")
+        db.update_batch_job(batch_id, status="failed", error=f"pipeline launch: {e}")
+
+
+async def _generate_one_track(*, title: str, genre: str, duration_sec: int,
+                              params: dict) -> int | None:
+    """기존 Suno generate 호출 + 완료까지 polling. 성공 시 새 track id, 실패 시 None."""
+    from .suno_provider import run_suno_generation
+
+    task_id = str(uuid.uuid4())
+    suno_params = {
+        "title": title,
+        "genre": genre,
+        "moods": params["moods"],
+        "instruments": params["instruments"],
+        "duration_sec": duration_sec,
+        "bpm": params["bpm"],
+        "key": params["key"],
+        "scale": params["scale"],
+        "prompt": params.get("prompt_modifier", ""),
+    }
+    db.create_task(task_id, suno_params, provider="suno")
+
+    # Suno background task — 우리가 await로 기다림 (BackgroundTasks 미사용)
+    asyncio.create_task(asyncio.to_thread(run_suno_generation, task_id, suno_params))
+
+    waited = 0
+    while waited < TRACK_GEN_TIMEOUT_S:
+        await asyncio.sleep(POLL_INTERVAL_S)
+        waited += POLL_INTERVAL_S
+        task = db.get_task(task_id)
+        if not task:
+            continue
+        status = task.get("status")
+        if status == "succeeded":
+            # task["track"] 또는 task["result"]["track"] 형태 시도, 없으면 task_id로 조회
+            tr = task.get("track")
+            if tr and isinstance(tr, dict):
+                return tr.get("id")
+            result = task.get("result", {}) or {}
+            if isinstance(result, dict) and isinstance(result.get("track"), dict):
+                return result["track"].get("id")
+            # Fallback: music_library에서 task_id로 검색
+            track = db.get_track_by_task_id(task_id)
+            if track:
+                return track.get("id")
+            return None
+        if status == "failed":
+            return None
+    return None  # timeout