feat: 实现后台在线更新功能

- 前端添加更新和重启按钮，支持一键更新 Release 构建
- 修复条件判断优先级问题，确保错误/成功状态正确显示
- 后端使用原子文件替换模式，确保更新过程安全可靠
- 在可执行文件同目录创建临时文件，保证 rename 原子性
- 删除未使用的 copyFile 函数，保持代码整洁

backend/internal/service/update_service.go

@@ -125,6 +125,7 @@ func (s *UpdateService) CheckUpdate(ctx context.Context, force bool) (*UpdateInf
 }
 
 // PerformUpdate downloads and applies the update
+// Uses atomic file replacement pattern for safe in-place updates
 func (s *UpdateService) PerformUpdate(ctx context.Context) error {
 	info, err := s.CheckUpdate(ctx, true)
 	if err != nil {
@@ -173,8 +174,11 @@ func (s *UpdateService) PerformUpdate(ctx context.Context) error {
 		return fmt.Errorf("failed to resolve symlinks: %w", err)
 	}
 
-	// Create temp directory for extraction
-	tempDir, err := os.MkdirTemp("", "sub2api-update-*")
+	exeDir := filepath.Dir(exePath)
+
+	// Create temp directory in the SAME directory as executable
+	// This ensures os.Rename is atomic (same filesystem)
+	tempDir, err := os.MkdirTemp(exeDir, ".sub2api-update-*")
 	if err != nil {
 		return fmt.Errorf("failed to create temp dir: %w", err)
 	}
@@ -199,23 +203,36 @@ func (s *UpdateService) PerformUpdate(ctx context.Context) error {
 		return fmt.Errorf("extraction failed: %w", err)
 	}
 
-	// Backup current binary
-	backupFile := exePath + ".backup"
-	if err := os.Rename(exePath, backupFile); err != nil {
-		return fmt.Errorf("backup failed: %w", err)
-	}
-
-	// Replace with new binary
-	if err := copyFile(newBinaryPath, exePath); err != nil {
-		os.Rename(backupFile, exePath)
-		return fmt.Errorf("replace failed: %w", err)
-	}
-
-	// Make executable
-	if err := os.Chmod(exePath, 0755); err != nil {
+	// Set executable permission before replacement
+	if err := os.Chmod(newBinaryPath, 0755); err != nil {
 		return fmt.Errorf("chmod failed: %w", err)
 	}
 
+	// Atomic replacement using rename pattern:
+	// 1. Rename current -> backup (atomic on Unix)
+	// 2. Rename new -> current (atomic on Unix, same filesystem)
+	// If step 2 fails, restore backup
+	backupPath := exePath + ".backup"
+
+	// Remove old backup if exists
+	os.Remove(backupPath)
+
+	// Step 1: Move current binary to backup
+	if err := os.Rename(exePath, backupPath); err != nil {
+		return fmt.Errorf("backup failed: %w", err)
+	}
+
+	// Step 2: Move new binary to target location (atomic, same filesystem)
+	if err := os.Rename(newBinaryPath, exePath); err != nil {
+		// Restore backup on failure
+		if restoreErr := os.Rename(backupPath, exePath); restoreErr != nil {
+			return fmt.Errorf("replace failed and restore failed: %w (restore error: %v)", err, restoreErr)
+		}
+		return fmt.Errorf("replace failed (restored backup): %w", err)
+	}
+
+	// Success - backup file is kept for rollback capability
+	// It will be cleaned up on next successful update
 	return nil
 }
 
@@ -515,23 +532,6 @@ func (s *UpdateService) extractBinary(archivePath, destPath string) error {
 	return err
 }
 
-func copyFile(src, dst string) error {
-	in, err := os.Open(src)
-	if err != nil {
-		return err
-	}
-	defer in.Close()
-
-	out, err := os.Create(dst)
-	if err != nil {
-		return err
-	}
-	defer out.Close()
-
-	_, err = io.Copy(out, in)
-	return err
-}
-
 func (s *UpdateService) getFromCache(ctx context.Context) (*UpdateInfo, error) {
 	data, err := s.rdb.Get(ctx, updateCacheKey).Result()
 	if err != nil {

frontend/src/api/admin/system.ts

@@ -40,9 +40,42 @@ export async function checkUpdates(force = false): Promise<VersionInfo> {
   return data;
 }
 
+export interface UpdateResult {
+  message: string;
+  need_restart: boolean;
+}
+
+/**
+ * Perform system update
+ * Downloads and applies the latest version
+ */
+export async function performUpdate(): Promise<UpdateResult> {
+  const { data } = await apiClient.post<UpdateResult>('/admin/system/update');
+  return data;
+}
+
+/**
+ * Rollback to previous version
+ */
+export async function rollback(): Promise<UpdateResult> {
+  const { data } = await apiClient.post<UpdateResult>('/admin/system/rollback');
+  return data;
+}
+
+/**
+ * Restart the service
+ */
+export async function restartService(): Promise<{ message: string }> {
+  const { data } = await apiClient.post<{ message: string }>('/admin/system/restart');
+  return data;
+}
+
 export const systemAPI = {
   getVersion,
   checkUpdates,
+  performUpdate,
+  rollback,
+  restartService,
 };
 
 export default systemAPI;

frontend/src/components/common/VersionBadge.vue

@@ -69,8 +69,63 @@
                 </p>
               </div>
 
-              <!-- Update available for source build - show git pull hint -->
-              <div v-if="hasUpdate && !isReleaseBuild" class="space-y-2">
+              <!-- Priority 1: Update error (must check before hasUpdate) -->
+              <div v-if="updateError" class="space-y-2">
+                <div class="flex items-center gap-3 p-3 rounded-lg bg-red-50 dark:bg-red-900/20 border border-red-200 dark:border-red-800/50">
+                  <div class="flex-shrink-0 w-8 h-8 rounded-full bg-red-100 dark:bg-red-900/50 flex items-center justify-center">
+                    <svg class="w-4 h-4 text-red-600 dark:text-red-400" fill="none" viewBox="0 0 24 24" stroke="currentColor" stroke-width="2">
+                      <path stroke-linecap="round" stroke-linejoin="round" d="M6 18L18 6M6 6l12 12" />
+                    </svg>
+                  </div>
+                  <div class="flex-1 min-w-0">
+                    <p class="text-sm font-medium text-red-700 dark:text-red-300">{{ t('version.updateFailed') }}</p>
+                    <p class="text-xs text-red-600/70 dark:text-red-400/70 truncate">{{ updateError }}</p>
+                  </div>
+                </div>
+
+                <!-- Retry button -->
+                <button
+                  @click="handleUpdate"
+                  :disabled="updating"
+                  class="w-full flex items-center justify-center gap-2 px-4 py-2 rounded-lg text-sm font-medium text-white bg-red-500 hover:bg-red-600 disabled:opacity-50 disabled:cursor-not-allowed transition-colors"
+                >
+                  {{ t('version.retry') }}
+                </button>
+              </div>
+
+              <!-- Priority 2: Update success - need restart -->
+              <div v-else-if="updateSuccess && needRestart" class="space-y-2">
+                <div class="flex items-center gap-3 p-3 rounded-lg bg-green-50 dark:bg-green-900/20 border border-green-200 dark:border-green-800/50">
+                  <div class="flex-shrink-0 w-8 h-8 rounded-full bg-green-100 dark:bg-green-900/50 flex items-center justify-center">
+                    <svg class="w-4 h-4 text-green-600 dark:text-green-400" fill="none" viewBox="0 0 24 24" stroke="currentColor" stroke-width="2">
+                      <path stroke-linecap="round" stroke-linejoin="round" d="M5 13l4 4L19 7" />
+                    </svg>
+                  </div>
+                  <div class="flex-1 min-w-0">
+                    <p class="text-sm font-medium text-green-700 dark:text-green-300">{{ t('version.updateComplete') }}</p>
+                    <p class="text-xs text-green-600/70 dark:text-green-400/70">{{ t('version.restartRequired') }}</p>
+                  </div>
+                </div>
+
+                <!-- Restart button -->
+                <button
+                  @click="handleRestart"
+                  :disabled="restarting"
+                  class="w-full flex items-center justify-center gap-2 px-4 py-2 rounded-lg text-sm font-medium text-white bg-green-500 hover:bg-green-600 disabled:opacity-50 disabled:cursor-not-allowed transition-colors"
+                >
+                  <svg v-if="restarting" class="animate-spin h-4 w-4" fill="none" viewBox="0 0 24 24">
+                    <circle class="opacity-25" cx="12" cy="12" r="10" stroke="currentColor" stroke-width="4"></circle>
+                    <path class="opacity-75" fill="currentColor" d="M4 12a8 8 0 018-8V0C5.373 0 0 5.373 0 12h4zm2 5.291A7.962 7.962 0 014 12H0c0 3.042 1.135 5.824 3 7.938l3-2.647z"></path>
+                  </svg>
+                  <svg v-else class="w-4 h-4" fill="none" viewBox="0 0 24 24" stroke="currentColor" stroke-width="2">
+                    <path stroke-linecap="round" stroke-linejoin="round" d="M4 4v5h.582m15.356 2A8.001 8.001 0 004.582 9m0 0H9m11 11v-5h-.581m0 0a8.003 8.003 0 01-15.357-2m15.357 2H15" />
+                  </svg>
+                  {{ restarting ? t('version.restarting') : t('version.restartNow') }}
+                </button>
+              </div>
+
+              <!-- Priority 3: Update available for source build - show git pull hint -->
+              <div v-else-if="hasUpdate && !isReleaseBuild" class="space-y-2">
                 <a
                   v-if="releaseInfo?.html_url && releaseInfo.html_url !== '#'"
                   :href="releaseInfo.html_url"
@@ -100,29 +155,53 @@
                 </div>
               </div>
 
-              <!-- Update available for release build - show download link -->
-              <a
-                v-else-if="hasUpdate && isReleaseBuild && releaseInfo?.html_url && releaseInfo.html_url !== '#'"
-                :href="releaseInfo.html_url"
-                target="_blank"
-                rel="noopener noreferrer"
-                class="flex items-center gap-3 p-3 rounded-lg bg-amber-50 dark:bg-amber-900/20 border border-amber-200 dark:border-amber-800/50 hover:bg-amber-100 dark:hover:bg-amber-900/30 transition-colors group"
-              >
-                <div class="flex-shrink-0 w-8 h-8 rounded-full bg-amber-100 dark:bg-amber-900/50 flex items-center justify-center">
-                  <svg class="w-4 h-4 text-amber-600 dark:text-amber-400" fill="none" viewBox="0 0 24 24" stroke="currentColor" stroke-width="2">
+              <!-- Priority 4: Update available for release build - show update button -->
+              <div v-else-if="hasUpdate && isReleaseBuild" class="space-y-2">
+                <!-- Update info card -->
+                <div class="flex items-center gap-3 p-3 rounded-lg bg-amber-50 dark:bg-amber-900/20 border border-amber-200 dark:border-amber-800/50">
+                  <div class="flex-shrink-0 w-8 h-8 rounded-full bg-amber-100 dark:bg-amber-900/50 flex items-center justify-center">
+                    <svg class="w-4 h-4 text-amber-600 dark:text-amber-400" fill="none" viewBox="0 0 24 24" stroke="currentColor" stroke-width="2">
+                      <path stroke-linecap="round" stroke-linejoin="round" d="M4 16v1a3 3 0 003 3h10a3 3 0 003-3v-1m-4-4l-4 4m0 0l-4-4m4 4V4" />
+                    </svg>
+                  </div>
+                  <div class="flex-1 min-w-0">
+                    <p class="text-sm font-medium text-amber-700 dark:text-amber-300">{{ t('version.updateAvailable') }}</p>
+                    <p class="text-xs text-amber-600/70 dark:text-amber-400/70">v{{ latestVersion }}</p>
+                  </div>
+                </div>
+
+                <!-- Update button -->
+                <button
+                  @click="handleUpdate"
+                  :disabled="updating"
+                  class="w-full flex items-center justify-center gap-2 px-4 py-2 rounded-lg text-sm font-medium text-white bg-primary-500 hover:bg-primary-600 disabled:opacity-50 disabled:cursor-not-allowed transition-colors"
+                >
+                  <svg v-if="updating" class="animate-spin h-4 w-4" fill="none" viewBox="0 0 24 24">
+                    <circle class="opacity-25" cx="12" cy="12" r="10" stroke="currentColor" stroke-width="4"></circle>
+                    <path class="opacity-75" fill="currentColor" d="M4 12a8 8 0 018-8V0C5.373 0 0 5.373 0 12h4zm2 5.291A7.962 7.962 0 014 12H0c0 3.042 1.135 5.824 3 7.938l3-2.647z"></path>
+                  </svg>
+                  <svg v-else class="w-4 h-4" fill="none" viewBox="0 0 24 24" stroke="currentColor" stroke-width="2">
                     <path stroke-linecap="round" stroke-linejoin="round" d="M4 16v1a3 3 0 003 3h10a3 3 0 003-3v-1m-4-4l-4 4m0 0l-4-4m4 4V4" />
                   </svg>
-                </div>
-                <div class="flex-1 min-w-0">
-                  <p class="text-sm font-medium text-amber-700 dark:text-amber-300">{{ t('version.updateAvailable') }}</p>
-                  <p class="text-xs text-amber-600/70 dark:text-amber-400/70">v{{ latestVersion }}</p>
-                </div>
-                <svg class="w-4 h-4 text-amber-500 dark:text-amber-400 group-hover:translate-x-0.5 transition-transform" fill="none" viewBox="0 0 24 24" stroke="currentColor" stroke-width="2">
-                  <path stroke-linecap="round" stroke-linejoin="round" d="M9 5l7 7-7 7" />
-                </svg>
-              </a>
+                  {{ updating ? t('version.updating') : t('version.updateNow') }}
+                </button>
 
-              <!-- GitHub link when up to date -->
+                <!-- View release link -->
+                <a
+                  v-if="releaseInfo?.html_url && releaseInfo.html_url !== '#'"
+                  :href="releaseInfo.html_url"
+                  target="_blank"
+                  rel="noopener noreferrer"
+                  class="flex items-center justify-center gap-1 text-xs text-gray-500 dark:text-dark-400 hover:text-gray-700 dark:hover:text-dark-200 transition-colors"
+                >
+                  {{ t('version.viewChangelog') }}
+                  <svg class="w-3 h-3" fill="none" viewBox="0 0 24 24" stroke="currentColor" stroke-width="2">
+                    <path stroke-linecap="round" stroke-linejoin="round" d="M10 6H6a2 2 0 00-2 2v10a2 2 0 002 2h10a2 2 0 002-2v-4M14 4h6m0 0v6m0-6L10 14" />
+                  </svg>
+                </a>
+              </div>
+
+              <!-- Priority 5: Up to date - show GitHub link -->
               <a
                 v-else-if="releaseInfo?.html_url && releaseInfo.html_url !== '#'"
                 :href="releaseInfo.html_url"
@@ -155,7 +234,7 @@
 import { ref, computed, onMounted, onBeforeUnmount } from 'vue';
 import { useI18n } from 'vue-i18n';
 import { useAuthStore } from '@/stores';
-import { checkUpdates, type VersionInfo, type ReleaseInfo } from '@/api/admin/system';
+import { checkUpdates, performUpdate, restartService, type VersionInfo, type ReleaseInfo } from '@/api/admin/system';
 
 const { t } = useI18n();
 
@@ -177,6 +256,13 @@ const hasUpdate = ref(false);
 const releaseInfo = ref<ReleaseInfo | null>(null);
 const buildType = ref('source'); // "source" or "release"
 
+// Update process states
+const updating = ref(false);
+const restarting = ref(false);
+const needRestart = ref(false);
+const updateError = ref('');
+const updateSuccess = ref(false);
+
 // Only show update check for release builds (binary/docker deployment)
 const isReleaseBuild = computed(() => buildType.value === 'release');
 
@@ -200,6 +286,10 @@ async function refreshVersion(force = true) {
     // Show update indicator for all build types
     hasUpdate.value = data.has_update;
     releaseInfo.value = data.release_info || null;
+    // Reset update states when refreshing
+    updateError.value = '';
+    updateSuccess.value = false;
+    needRestart.value = false;
   } catch (error) {
     console.error('Failed to check updates:', error);
   } finally {
@@ -207,6 +297,45 @@ async function refreshVersion(force = true) {
   }
 }
 
+async function handleUpdate() {
+  if (updating.value) return;
+
+  updating.value = true;
+  updateError.value = '';
+  updateSuccess.value = false;
+
+  try {
+    const result = await performUpdate();
+    updateSuccess.value = true;
+    needRestart.value = result.need_restart;
+    hasUpdate.value = false;
+  } catch (error: unknown) {
+    const err = error as { response?: { data?: { message?: string } }; message?: string };
+    updateError.value = err.response?.data?.message || err.message || t('version.updateFailed');
+  } finally {
+    updating.value = false;
+  }
+}
+
+async function handleRestart() {
+  if (restarting.value) return;
+
+  restarting.value = true;
+
+  try {
+    await restartService();
+    // Service will restart, page will reload automatically or show disconnected
+  } catch (error) {
+    // Expected - connection will be lost during restart
+    console.log('Service restarting...');
+  }
+
+  // Show restarting state for a while, then reload
+  setTimeout(() => {
+    window.location.reload();
+  }, 3000);
+}
+
 function handleClickOutside(event: MouseEvent) {
   const target = event.target as Node;
   const button = (event.target as Element).closest('button');

frontend/src/i18n/locales/en.ts

@@ -1023,9 +1023,18 @@ export default {
     noReleaseNotes: 'No release notes',
     viewUpdate: 'View Update',
     viewRelease: 'View Release',
+    viewChangelog: 'View Changelog',
     refresh: 'Refresh',
     sourceMode: 'Source Build',
-    sourceModeHint: 'Update detection is disabled for source builds. Use git pull to update.',
+    sourceModeHint: 'Source build, use git pull to update',
+    updateNow: 'Update Now',
+    updating: 'Updating...',
+    updateComplete: 'Update Complete',
+    updateFailed: 'Update Failed',
+    restartRequired: 'Please restart the service to apply the update',
+    restartNow: 'Restart Now',
+    restarting: 'Restarting...',
+    retry: 'Retry',
   },
 
   // User Subscriptions Page

frontend/src/i18n/locales/zh.ts

@@ -1202,9 +1202,18 @@ export default {
     noReleaseNotes: '暂无更新日志',
     viewUpdate: '查看更新',
     viewRelease: '查看发布',
+    viewChangelog: '查看更新日志',
     refresh: '刷新',
     sourceMode: '源码构建',
-    sourceModeHint: '源码构建模式不支持更新检测，请使用 git pull 更新代码。',
+    sourceModeHint: '源码构建请使用 git pull 更新',
+    updateNow: '立即更新',
+    updating: '正在更新...',
+    updateComplete: '更新完成',
+    updateFailed: '更新失败',
+    restartRequired: '请重启服务以应用更新',
+    restartNow: '立即重启',
+    restarting: '正在重启...',
+    retry: '重试',
   },
 
   // User Subscriptions Page