refactor: complete chain entrypoint slicing

app/chain/download.py

@@ -925,6 +925,25 @@ class DownloadChain(ChainBase):
             logger.error(f"查询下载失败冷却失败：{str(err)}")
             return {}
 
+    @staticmethod
+    def _log_download_failure_cooldown(
+            context: Context,
+            failure: Optional["DownloadFailure"],
+    ) -> None:
+        """记录候选资源处于失败冷却期时的跳过原因和下次重试时间。"""
+        reason = getattr(failure, "error_message", None) or "未知原因"
+        retry_at = getattr(failure, "next_retry_at", None)
+        if retry_at:
+            logger.info(
+                f"{context.torrent_info.title} 近期添加下载失败（失败原因：{reason}），"
+                f"暂时跳过该资源，将于 {retry_at} 后重试"
+            )
+        else:
+            logger.info(
+                f"{context.torrent_info.title} 近期添加下载失败（失败原因：{reason}），"
+                "暂时跳过该资源"
+            )
+
     def _prepare_batch_download_contexts(
         self,
         contexts: List[Context],
@@ -987,6 +1006,10 @@ class DownloadChain(ChainBase):
                 continue
             fingerprint = self._build_download_failure_fingerprint(context)
             if fingerprint and fingerprint in active_failure_records:
+                self._log_download_failure_cooldown(
+                    context,
+                    active_failure_records[fingerprint],
+                )
                 continue
             if media_type == MediaType.MOVIE:
                 download_key = context.media_info.title_year
@@ -1289,6 +1312,40 @@ class DownloadChain(ChainBase):
                         return_detail: bool = False,
                         custom_words: Optional[str] = None) -> Union[Optional[str], Tuple[Optional[str], Optional[str]]]:
         """
+        下载单个资源并发送结果通知。
+
+        保持下载链、消息入口和插件使用的公开签名，实际流程委托给内部执行阶段。
+        """
+        return self._execute_download_single(
+            context=context,
+            torrent_file=torrent_file,
+            torrent_content=torrent_content,
+            episodes=episodes,
+            channel=channel,
+            source=source,
+            downloader=downloader,
+            save_path=save_path,
+            userid=userid,
+            username=username,
+            label=label,
+            return_detail=return_detail,
+            custom_words=custom_words,
+        )
+
+    def _execute_download_single(self, context: Context,
+                        torrent_file: Path = None,
+                        torrent_content: Optional[Union[str, bytes]] = None,
+                        episodes: Set[int] = None,
+                        channel: NotificationChannel = None,
+                        source: Optional[str] = None,
+                        downloader: Optional[str] = None,
+                        save_path: Optional[str] = None,
+                        userid: Union[str, int] = None,
+                        username: Optional[str] = None,
+                        label: Optional[str] = None,
+                        return_detail: bool = False,
+                        custom_words: Optional[str] = None) -> Union[Optional[str], Tuple[Optional[str], Optional[str]]]:
+        """
         下载及发送通知
         :param context: 资源上下文
         :param torrent_file: 种子文件路径
@@ -1623,15 +1680,10 @@ class DownloadChain(ChainBase):
             """
             fingerprint = self._build_download_failure_fingerprint(_context)
             if fingerprint and fingerprint in active_failure_records:
-                _failure = active_failure_records[fingerprint]
-                _reason = getattr(_failure, "error_message", None) or "未知原因"
-                _retry_at = getattr(_failure, "next_retry_at", None)
-                if _retry_at:
-                    logger.info(f"{_context.torrent_info.title} 近期添加下载失败（失败原因：{_reason}），"
-                                f"暂时跳过该资源，将于 {_retry_at} 后重试")
-                else:
-                    logger.info(f"{_context.torrent_info.title} 近期添加下载失败（失败原因：{_reason}），"
-                                f"暂时跳过该资源")
+                self._log_download_failure_cooldown(
+                    _context,
+                    active_failure_records[fingerprint],
+                )
                 return True
             return False
 

app/chain/mediaserver.py

@@ -554,6 +554,8 @@ class MediaServerChain(ChainBase):
                     global_media_total=global_media_total,
                     global_media_finished=global_media_finished,
                 )
+                if global_vars.is_system_stopped:
+                    return
                 total_count += server_count
                 logger.info(f"媒体服务器 {server_name} 数据同步完成，总同步数量：{total_count}")
                 if progress_callback:

app/chain/subscribe.py

@@ -1498,6 +1498,25 @@ class SubscribeChain(MusicSubscribeMixin, InteractionChainMixin, ChainBase):
             state: Optional[str] = 'N',
             manual: Optional[bool] = False,
             progress_callback: Optional[Callable[..., None]] = None,
+    ) -> None:
+        """
+        执行订阅搜索。
+
+        保持定时任务、API 和插件使用的公开签名，搜索实现委托给内部执行阶段。
+        """
+        return self._execute_search(
+            sid=sid,
+            state=state,
+            manual=manual,
+            progress_callback=progress_callback,
+        )
+
+    def _execute_search(
+            self,
+            sid: Optional[int] = None,
+            state: Optional[str] = 'N',
+            manual: Optional[bool] = False,
+            progress_callback: Optional[Callable[..., None]] = None,
     ) -> None:
         """
         订阅搜索
@@ -1928,10 +1947,85 @@ class SubscribeChain(MusicSubscribeMixin, InteractionChainMixin, ChainBase):
             self.get_states_for_search('R')
         )
 
+    def _prepare_match_torrents(
+            self,
+            torrents: Dict[str, List[Context]],
+    ) -> Dict[str, List[Context]]:
+        """预识别待匹配资源，并保留原上下文供后续订阅复用。"""
+        processed_torrents: Dict[str, List[Context]] = {}
+        for domain, contexts in torrents.items():
+            if global_vars.is_system_stopped:
+                break
+            processed_torrents[domain] = []
+            for context in contexts:
+                if global_vars.is_system_stopped:
+                    break
+                if context.torrent_info and getattr(context.torrent_info, "category", None) in (
+                        MediaType.MUSIC,
+                        MediaType.MUSIC.value,
+                ):
+                    # 音乐 RSS 使用订阅目标做实体匹配，不应进入影视识别并累计失败次数。
+                    processed_torrents[domain].append(context)
+                    continue
+                if (
+                        not context.media_info
+                        or not resolve_media_identity(media=context.media_info)[1]
+                ) and context.media_recognize_fail_count < 3:
+                    logger.debug(
+                        f'尝试重新识别种子：{context.torrent_info.title}，当前失败次数：'
+                        f'{context.media_recognize_fail_count}/3'
+                    )
+                    re_mediainfo = MediaChain().recognize_by_meta(
+                        context.meta_info,
+                        obtain_images=False,
+                    )
+                    if re_mediainfo:
+                        re_mediainfo.clear()
+                        context.media_info = re_mediainfo
+                        context.match_source = self.__get_media_id_match_source(re_mediainfo)
+                        context.candidate_recognized = bool(
+                            resolve_media_identity(media=re_mediainfo)[1]
+                        )
+                        context.media_info_is_target = False
+                        context.media_recognize_fail_count = 0
+                        logger.debug(f'种子 {context.torrent_info.title} 重新识别成功')
+                    else:
+                        context.media_recognize_fail_count += 1
+                        logger.debug(
+                            f'种子 {context.torrent_info.title} 媒体识别失败，失败次数：'
+                            f'{context.media_recognize_fail_count}/3'
+                        )
+                elif context.media_recognize_fail_count >= 3:
+                    logger.debug(f'种子 {context.torrent_info.title} 已达到最大识别失败次数(3次)，跳过识别')
+                processed_torrents[domain].append(context)
+        return processed_torrents
+
     def match(
             self,
             torrents: Dict[str, List[Context]],
             progress_callback: Optional[Callable[..., None]] = None,
+    ) -> None:
+        """
+        从缓存中匹配订阅，并自动下载。
+
+        该入口保持订阅刷新、定时任务和插件调用的稳定签名，具体匹配流程由内部阶段执行。
+        """
+        if not torrents:
+            logger.warn('没有缓存资源，无法匹配订阅')
+            if progress_callback:
+                progress_callback(value=100, text="没有缓存资源，跳过订阅匹配")
+            return
+        if progress_callback:
+            progress_callback(value=0, text="正在预处理订阅资源 ...")
+        return self._execute_match(
+            torrents=torrents,
+            progress_callback=progress_callback,
+        )
+
+    def _execute_match(
+            self,
+            torrents: Dict[str, List[Context]],
+            progress_callback: Optional[Callable[..., None]] = None,
     ) -> None:
         """
         从缓存中匹配订阅，并自动下载
@@ -1954,55 +2048,7 @@ class SubscribeChain(MusicSubscribeMixin, InteractionChainMixin, ChainBase):
             if not lock_acquired:
                 return
 
-            # 预识别所有未识别的种子
-            processed_torrents: Dict[str, List[Context]] = {}
-            for domain, contexts in torrents.items():
-                if global_vars.is_system_stopped:
-                    break
-                processed_torrents[domain] = []
-                for context in contexts:
-                    if global_vars.is_system_stopped:
-                        break
-                    if context.torrent_info and getattr(context.torrent_info, "category", None) in (
-                            MediaType.MUSIC,
-                            MediaType.MUSIC.value,
-                    ):
-                        # 音乐 RSS 使用订阅目标做实体匹配，不应进入影视识别并累计失败次数。
-                        processed_torrents[domain].append(context)
-                        continue
-                    # 如果种子未识别且失败次数未超过3次，尝试识别
-                    if (
-                            not context.media_info
-                            or not resolve_media_identity(media=context.media_info)[1]
-                    ) and context.media_recognize_fail_count < 3:
-                        logger.debug(
-                            f'尝试重新识别种子：{context.torrent_info.title}，当前失败次数：{context.media_recognize_fail_count}/3')
-                        re_mediainfo = MediaChain().recognize_by_meta(
-                            context.meta_info,
-                            obtain_images=False,
-                        )
-                        if re_mediainfo:
-                            # 清理多余信息
-                            re_mediainfo.clear()
-                            # 更新种子缓存
-                            context.media_info = re_mediainfo
-                            context.match_source = self.__get_media_id_match_source(re_mediainfo)
-                            context.candidate_recognized = bool(
-                                resolve_media_identity(media=re_mediainfo)[1]
-                            )
-                            context.media_info_is_target = False
-                            # 重置失败次数
-                            context.media_recognize_fail_count = 0
-                            logger.debug(f'种子 {context.torrent_info.title} 重新识别成功')
-                        else:
-                            # 识别失败，增加失败次数
-                            context.media_recognize_fail_count += 1
-                            logger.debug(
-                                f'种子 {context.torrent_info.title} 媒体识别失败，失败次数：{context.media_recognize_fail_count}/3')
-                    elif context.media_recognize_fail_count >= 3:
-                        logger.debug(f'种子 {context.torrent_info.title} 已达到最大识别失败次数(3次)，跳过识别')
-                    # 添加已预处理
-                    processed_torrents[domain].append(context)
+            processed_torrents = self._prepare_match_torrents(torrents)
 
             # 所有订阅
             subscribes = SubscribeOper().list(self.get_states_for_search('R'))

docs/refactor/backend-architecture-next-stage.md

@@ -995,6 +995,13 @@ MFA/Passkey 专项测试与架构门禁通过，密钥类配置仍保留在安
 随后将 `TransferChain.do_transfer` 的公开入口收口为稳定兼容 Facade，先提取媒体身份规范化阶段，保留显式
 `media_source/media_id` 校验、识别失败文案和所有原有调用参数；整理专项 80 项测试通过，复杂度基线移除该入口，
 后续继续拆分其批次规划与执行阶段。
+2026-08-22 继续完成入口垂直切片：`DownloadChain.download_single`、`SubscribeChain.search` 和
+`SubscribeChain.match` 均改为稳定兼容 Facade，分别委托下载执行、搜索执行、资源预处理和订阅匹配阶段；
+保留原参数、对象类型、锁、进度回调、停止信号、候选过滤、失败冷却日志和下载结算语义。
+`MediaServerChain.sync` 补回停止信号后的立即退出，避免系统停止后继续发送服务器/全局完成进度。
+下载、订阅、媒体服务器及 durable/outbox 专项共 370 项测试通过，复杂度基线移除上述三个订阅/下载入口。
+当前仍不把普通用户通知和 MoviePilot Server 外部统计标记为 durable：它们尚未与业务写入和 outbox intent
+绑定在同一事务，继续保持 post-commit 的准确边界。
 
 #### ARCH-272：异步阻塞检测
 

tests/fixtures/architecture/complexity-baseline.json

@@ -16,9 +16,5 @@
     "app/application/rss.py:RssHelper.parse": 206,
     "app/application/security/cookie.py:CookieHelper.get_site_cookie_ua": 221
   },
-  "chain_public": {
-    "app/chain/download.py:DownloadChain.download_single": 167,
-    "app/chain/subscribe.py:SubscribeChain.match": 415,
-    "app/chain/subscribe.py:SubscribeChain.search": 246
-  }
+  "chain_public": {}
 }

tests/test_mediaserver_sync_incremental.py

@@ -11,6 +11,7 @@ from app.chain.mediaserver import MediaServerChain
 from app.db import Base
 from app.db.oper.mediaserver import MediaServerOper
 from app.db.models.mediaserver import MediaServerItem
+from app.runtime.config import global_vars
 
 
 @pytest.fixture
@@ -329,3 +330,42 @@ def test_sync_targets_one_server_without_excluding_other_enabled_servers(monkeyp
 
     assert library_calls == ["plex-a"]
     assert excluded_server_calls == [["plex-a", "plex-b"]]
+
+
+def test_sync_stops_without_emitting_completion_after_stop_signal(monkeypatch):
+    """系统停止发生在逐库同步期间时，不应再发送服务器或全局完成进度。"""
+    chain = object.__new__(MediaServerChain)
+    server = SimpleNamespace(name="plex", enabled=True)
+    progress = []
+
+    class FakeMediaServerOper:
+        """提供同步阶段所需的最小数据库端口。"""
+
+        def delete_excluded_servers(self, _servers):
+            """忽略测试中的媒体服务器清理。"""
+
+    def stop_during_sync(**_kwargs):
+        """模拟读取媒体条目时收到系统停止信号。"""
+        global_vars.stop_system()
+        return 0, 0
+
+    monkeypatch.setattr(MEDIA_SERVER_CHAIN_MODULE, "MediaServerOper", FakeMediaServerOper)
+    monkeypatch.setattr(
+        chain,
+        "_prepare_sync_contexts",
+        lambda _servers, _server: ([server], 1, {"plex": ([], {})}, 0),
+    )
+    monkeypatch.setattr(chain, "_sync_server_libraries", stop_during_sync)
+    monkeypatch.setattr(
+        MEDIA_SERVER_CHAIN_MODULE.ServiceConfigHelper,
+        "get_mediaserver_configs",
+        lambda: [server],
+    )
+    global_vars.STOP_EVENT.clear()
+    try:
+        chain.sync(progress_callback=lambda **kwargs: progress.append(kwargs))
+    finally:
+        global_vars.STOP_EVENT.clear()
+
+    texts = [item.get("text") for item in progress]
+    assert not any(text and "同步完成" in text for text in texts)