feat(video-render): providers/seedance.py — Seedance 2.0 BytePlus client (SP-7)

POST /seedance/v1/videos → GET /videos/{id} 폴링 (8초 × 60) → output.video_url 다운로드.
Bearer 토큰. resolution 1080p/720p/2k, duration 4~15s.
references 배열로 image-to-video 지원.
Plan-B-Video Phase 2.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

services/video-render/providers/seedance.py

@@ -0,0 +1,121 @@
+"""Seedance 2.0 video generation — ByteDance Volcano Engine (BytePlus 국제 endpoint).
+
+POST https://api.byteplus.com/seedance/v1/videos → GET /videos/{id} 폴링 → output.video_url 다운로드.
+"""
+from __future__ import annotations
+
+import logging
+import os
+import time
+from typing import Optional
+
+import requests
+
+from nas_client import webhook_update_task
+
+logger = logging.getLogger(__name__)
+
+SEEDANCE_BASE_URL = "https://api.byteplus.com/seedance/v1"
+VIDEO_MEDIA_ROOT = os.getenv("VIDEO_MEDIA_ROOT", "/mnt/nas/webpage/data/video")
+VIDEO_MEDIA_URL_PREFIX = os.getenv("VIDEO_MEDIA_URL_PREFIX", "/media/video")
+
+POLL_INTERVAL = 8   # Seedance는 30~120초
+POLL_MAX_ATTEMPTS = 60
+
+DEFAULT_MODEL = "seedance-2.0"
+
+
+def _headers() -> dict:
+    api_key = os.getenv("SEEDANCE_API_KEY", "")
+    return {
+        "Authorization": f"Bearer {api_key}",
+        "Content-Type": "application/json",
+    }
+
+
+def run_seedance_generation(task_id: str, params: dict) -> None:
+    """Seedance로 영상 생성 → mp4 → NAS SMB → webhook."""
+    try:
+        if not os.getenv("SEEDANCE_API_KEY"):
+            webhook_update_task(task_id, "failed", 0, "", error="SEEDANCE_API_KEY 미설정")
+            return
+
+        webhook_update_task(task_id, "processing", 5, "Seedance API 호출 중...")
+
+        body = {
+            "model": params.get("model") or DEFAULT_MODEL,
+            "prompt": params["prompt"][:2000],
+            "resolution": params.get("resolution", "1080p"),
+            "duration": params.get("duration", 5),
+            "aspect_ratio": params.get("aspect_ratio", "16:9"),
+        }
+        if params.get("negative_prompt"):
+            body["negative_prompt"] = params["negative_prompt"]
+        if params.get("image_url"):
+            body["references"] = [{"type": "image", "data": params["image_url"], "role": "subject"}]
+        if params.get("audio") is not None:
+            body["audio"] = bool(params["audio"])
+        if params.get("seed") is not None:
+            body["seed"] = int(params["seed"])
+
+        resp = requests.post(f"{SEEDANCE_BASE_URL}/videos", headers=_headers(), json=body, timeout=30)
+        if resp.status_code not in (200, 201):
+            webhook_update_task(task_id, "failed", 0, "",
+                                error=f"Seedance API 오류: {resp.status_code} {resp.text[:300]}")
+            return
+
+        body_json = resp.json()
+        job_id = body_json.get("id", "")
+        if not job_id:
+            webhook_update_task(task_id, "failed", 0, "", error="Seedance 응답에 id 없음")
+            return
+
+        webhook_update_task(task_id, "processing", 15, "Seedance 작업 등록됨")
+
+        # 폴링
+        video_url = None
+        for attempt in range(POLL_MAX_ATTEMPTS):
+            time.sleep(POLL_INTERVAL)
+            fetch = requests.get(f"{SEEDANCE_BASE_URL}/videos/{job_id}",
+                                 headers=_headers(), timeout=30)
+            if fetch.status_code != 200:
+                continue
+            fd = fetch.json()
+            status = fd.get("status", "")
+            scaled = min(15 + int((attempt / POLL_MAX_ATTEMPTS) * 65), 79)
+            webhook_update_task(task_id, "processing", scaled, f"Seedance 생성 중... ({status})")
+
+            if status == "completed":
+                video_url = (fd.get("output") or {}).get("video_url", "")
+                break
+            elif status == "failed":
+                err = fd.get("error") or "Seedance 작업 실패"
+                webhook_update_task(task_id, "failed", 0, "", error=str(err)[:300])
+                return
+        else:
+            webhook_update_task(task_id, "failed", 0, "", error="Seedance 폴링 timeout (10분)")
+            return
+
+        if not video_url:
+            webhook_update_task(task_id, "failed", 0, "", error="Seedance 완료했으나 video_url 없음")
+            return
+
+        webhook_update_task(task_id, "processing", 85, "Seedance 결과 다운로드 중...")
+        filename = f"{task_id}.mp4"
+        os.makedirs(VIDEO_MEDIA_ROOT, exist_ok=True)
+        file_path = os.path.join(VIDEO_MEDIA_ROOT, filename)
+
+        dl = requests.get(video_url, stream=True, timeout=300)
+        dl.raise_for_status()
+        with open(file_path, "wb") as f:
+            for chunk in dl.iter_content(chunk_size=8192):
+                f.write(chunk)
+
+        local_url = f"{VIDEO_MEDIA_URL_PREFIX}/{filename}"
+        webhook_update_task(task_id, "succeeded", 100, "Seedance 생성 완료", video_url=local_url)
+
+    except requests.Timeout:
+        webhook_update_task(task_id, "failed", 0, "", error="Seedance API 타임아웃")
+    except Exception as e:
+        logger.exception("Seedance generation error task=%s", task_id)
+        webhook_update_task(task_id, "failed", 0, "", error=str(e))