排课计算、课表发布、补考自动编排三类任务统一接入消息系统。

业务任务与 Outbox 消息同一事务落库，避免“数据库成功但消息没发出去”。
RabbitMQ 使用持久化消息、发布确认、手动 ACK、Quorum Queue、死信队列。
增加处理租约、心跳、异常重试、最大重试次数和幂等状态控制。
保留 InMemory 模式，开发环境无需安装 RabbitMQ。
支持多实例竞争消费，后续可以横向扩容。
新增 /health/messaging 消息系统健康检查。

src/Jiaowu.Api/Program.cs

@@ -1,6 +1,7 @@
 using System.Text;
 using System.Text.Json.Serialization;
 using Jiaowu.Api.Domain.Identity;
+using Jiaowu.Api.Infrastructure.BackgroundJobs;
 using Jiaowu.Api.Infrastructure.Configuration;
 using Jiaowu.Api.Infrastructure.Auth;
 using Jiaowu.Api.Infrastructure.Caching;
@@ -70,6 +71,12 @@ var cacheOptions = builder.Configuration
 var officialDocumentOptions = builder.Configuration
     .GetSection(OfficialDocumentOptions.SectionName)
     .Get<OfficialDocumentOptions>() ?? new OfficialDocumentOptions();
+var backgroundJobOptions = builder.Configuration
+    .GetSection(BackgroundJobOptions.SectionName)
+    .Get<BackgroundJobOptions>() ?? new BackgroundJobOptions();
+var rabbitMqOptions = builder.Configuration
+    .GetSection(RabbitMqOptions.SectionName)
+    .Get<RabbitMqOptions>() ?? new RabbitMqOptions();
 
 if (string.IsNullOrWhiteSpace(officialDocumentOptions.InstitutionName) ||
     string.IsNullOrWhiteSpace(officialDocumentOptions.IssuingOffice) ||
@@ -119,9 +126,46 @@ if (cacheOptions.ReferenceExpirationMinutes is < 1 or > 1440 ||
         "Cache 缓存时间或 MaximumPayloadKilobytes 超出允许范围。");
 }
 
+if (!backgroundJobOptions.Transport.Equals(
+        "InMemory",
+        StringComparison.OrdinalIgnoreCase) &&
+    !backgroundJobOptions.UsesRabbitMq)
+{
+    throw new InvalidOperationException(
+        "BackgroundJobs:Transport 仅支持 InMemory 或 RabbitMq。");
+}
+if (backgroundJobOptions.PollIntervalMilliseconds is < 100 or > 30000 ||
+    backgroundJobOptions.LeaseSeconds is < 30 or > 3600 ||
+    backgroundJobOptions.PrefetchCount is < 1 or > 100 ||
+    backgroundJobOptions.ProcessingAttemptLimit is < 1 or > 100 ||
+    string.IsNullOrWhiteSpace(backgroundJobOptions.Exchange) ||
+    string.IsNullOrWhiteSpace(backgroundJobOptions.QueuePrefix))
+{
+    throw new InvalidOperationException("BackgroundJobs 配置超出允许范围。");
+}
+if (backgroundJobOptions.UsesRabbitMq &&
+    (string.IsNullOrWhiteSpace(rabbitMqOptions.HostName) ||
+     rabbitMqOptions.Port is < 1 or > 65535 ||
+     string.IsNullOrWhiteSpace(rabbitMqOptions.UserName) ||
+     string.IsNullOrWhiteSpace(rabbitMqOptions.Password) ||
+     string.IsNullOrWhiteSpace(rabbitMqOptions.VirtualHost)))
+{
+    throw new InvalidOperationException("RabbitMq 连接配置不完整。");
+}
+if (backgroundJobOptions.UsesRabbitMq &&
+    !builder.Environment.IsDevelopment() &&
+    (rabbitMqOptions.UserName.Equals("guest", StringComparison.OrdinalIgnoreCase) ||
+     rabbitMqOptions.Password == "guest"))
+{
+    throw new InvalidOperationException(
+        "生产环境启用 RabbitMQ 时不能使用默认 guest 凭据。");
+}
+
 builder.Services.AddSingleton(databaseOptions);
 builder.Services.AddSingleton(cacheOptions);
 builder.Services.AddSingleton(officialDocumentOptions);
+builder.Services.AddSingleton(backgroundJobOptions);
+builder.Services.AddSingleton(rabbitMqOptions);
 builder.Services.Configure<OfficialDocumentOptions>(
     builder.Configuration.GetSection(OfficialDocumentOptions.SectionName));
 builder.Services.AddDbContextPool<AppDbContext>(options =>
@@ -218,19 +262,29 @@ builder.Services.AddScoped<AutomaticScheduleGenerator>();
 builder.Services.AddScoped<PersonalCalendarService>();
 builder.Services.AddScoped<ClassroomReservationAvailabilityService>();
 builder.Services.AddScoped<AutomaticScheduleJobProcessor>();
-builder.Services.AddSingleton<AutomaticScheduleJobQueue>();
-builder.Services.AddHostedService<AutomaticScheduleJobWorker>();
 builder.Services.AddScoped<SchedulePlanPublisher>();
 builder.Services.AddScoped<SchedulePublishJobProcessor>();
-builder.Services.AddSingleton<SchedulePublishJobQueue>();
-builder.Services.AddHostedService<SchedulePublishJobWorker>();
 builder.Services.AddHostedService<WarningCheckWorker>();
 builder.Services.AddScoped<ExamArrangementService>();
 builder.Services.AddScoped<MakeupExamEligibilityService>();
 builder.Services.AddScoped<MakeupExamArrangementService>();
-builder.Services.AddSingleton<MakeupExamAutoJobQueue>();
-builder.Services.AddHostedService<MakeupExamAutoJobWorker>();
 builder.Services.AddScoped<MakeupExamAutoJobProcessor>();
+builder.Services.AddSingleton<BackgroundJobRunner>();
+if (backgroundJobOptions.UsesRabbitMq)
+{
+    builder.Services.AddSingleton<
+        IBackgroundJobTransport,
+        RabbitMqBackgroundJobTransport>();
+    builder.Services.AddHostedService<RabbitMqBackgroundJobWorker>();
+}
+else
+{
+    builder.Services.AddSingleton<InMemoryBackgroundJobTransport>();
+    builder.Services.AddSingleton<IBackgroundJobTransport>(services =>
+        services.GetRequiredService<InMemoryBackgroundJobTransport>());
+    builder.Services.AddHostedService<InMemoryBackgroundJobWorker>();
+}
+builder.Services.AddHostedService<BackgroundJobOutboxPublisher>();
 builder.Services.AddSingleton<IOfficialDocumentPdfGenerator, OfficialDocumentPdfGenerator>();
 builder.Services.AddScoped<OfficialDocumentService>();
 
@@ -391,6 +445,7 @@ app.MapGet("/health/live", () => Results.Ok(new { Status = "healthy" }))
 app.MapGet("/health", CheckDatabaseHealthAsync).AllowAnonymous();
 app.MapGet("/health/ready", CheckDatabaseHealthAsync).AllowAnonymous();
 app.MapGet("/health/cache", CheckCacheHealthAsync).AllowAnonymous();
+app.MapGet("/health/messaging", CheckMessagingHealthAsync).AllowAnonymous();
 app.MapFallback(async context =>
 {
     if (context.Request.Path.StartsWithSegments("/api") ||
@@ -477,4 +532,17 @@ static async Task<IResult> CheckCacheHealthAsync(
     }
 }
 
+static async Task<IResult> CheckMessagingHealthAsync(
+    IBackgroundJobTransport transport,
+    CancellationToken cancellationToken)
+{
+    var healthy = await transport.CheckHealthAsync(cancellationToken);
+    var backend = transport.IsDurable ? "rabbitmq" : "memory";
+    return healthy
+        ? Results.Ok(new { Status = "healthy", Backend = backend })
+        : Results.Json(
+            new { Status = "unhealthy", Backend = backend },
+            statusCode: StatusCodes.Status503ServiceUnavailable);
+}
+
 public partial class Program;