.Net Core之RabbitMQ

.Net Core之RabbitMQ

.Net Core下使用RabbitMQ很方便，不过这里还是采用了EasyNetQ这一二次封装的库

• EasyNetQ对Rabbit原生接口进行了二次封装，提供了IBus作为入口，入门使用的话更加方便，要想使用，只需要在Startup的时候助于一个Singleton的IBus即可：

  service.AddSingleton(RabbitHutch.CreateBus(rabbitMqConnection));
  

• EasyNetQ还提供了一个自动订阅的方法，可以方便一次性自动订阅-AutoSubscriber：

  public static class EasyNetQExtension
  {
      private static void InternalInitEasyNetQ(IServiceCollection service, string rabbitMqConnection)
      {
          service.AddSingleton(RabbitHutch.CreateBus(rabbitMqConnection));
          service.AddSingleton<IAutoSubscriberMessageDispatcher, ConsumerMessageDispatcher>(
              serviceProvider => new ConsumerMessageDispatcher(
                  serviceProvider, serviceProvider.GetRequiredService<ILogger<ConsumerMessageDispatcher>>()));
  
          var consumerTypes = Assembly.GetExecutingAssembly().GetTypes()
                                      .Where(x => x.IsClass && !x.IsAbstract && !x.IsInterface)
                                      .Where(x => x.GetInterfaces().Any(t => t.Name == typeof(IConsume<>).Name));
          foreach (var consumerType in consumerTypes)
          {
              service.AddTransient(consumerType);
          }
  
          var consumerAsyncTypes = Assembly.GetExecutingAssembly().GetTypes()
                                           .Where(x => x.IsClass && !x.IsAbstract && !x.IsInterface)
                                           .Where(x => x.GetInterfaces().Any(t => t.Name == typeof(IConsumeAsync<>).Name));
          foreach (var consumerAsyncType in consumerAsyncTypes)
          {
              service.AddTransient(consumerAsyncType);
          }
      }
  
      public static void AddEasyNetQ(this IServiceCollection service, string rabbitMqConnectionString)
      {
          InternalInitEasyNetQ(service, rabbitMqConnectionString);
      }
  
      public static void UseEasyNetQ(this IApplicationBuilder app)
      {
          var bus = app.ApplicationServices.GetRequiredService<IBus>();
          var autoSubscriber = new AutoSubscriber(bus, "Consumer")
          {
              //由于要配合EF Core使用，而EasyNetQ默认的IAutoSubscriberMessageDispatcher对依赖注入的DBContext支持的不太好，需要自定义Dispatcher
              AutoSubscriberMessageDispatcher = app.ApplicationServices.GetRequiredService<IAutoSubscriberMessageDispatcher>()
          };
          autoSubscriber.Subscribe(Assembly.GetExecutingAssembly());
          autoSubscriber.SubscribeAsync(Assembly.GetExecutingAssembly());
      }
  }
  

  public class ConsumerMessageDispatcher : IAutoSubscriberMessageDispatcher
  {
      private readonly IServiceProvider _serviceProvider;
      private readonly ILogger<ConsumerMessageDispatcher> _logger;
  
      public ConsumerMessageDispatcher(IServiceProvider serviceProvider, ILogger<ConsumerMessageDispatcher> logger)
      {
          _serviceProvider = serviceProvider;
          _logger = logger;
      }
  
      public void Dispatch<TMessage, TConsumer>(TMessage message) where TMessage : class where TConsumer : class, IConsume<TMessage>
      {
          try
          {
              TConsumer consumer = _serviceProvider.GetRequiredService<TConsumer>();
              consumer.Consume(message);
          }
          catch (Exception exception)
          {
              throw;
          }
      }
  
      public async Task DispatchAsync<TMessage, TConsumer>(TMessage message) where TMessage : class where TConsumer : class, IConsumeAsync<TMessage>
      {
          try
          {
              TConsumer consumer = _serviceProvider.GetRequiredService<TConsumer>();
              await consumer.ConsumeAsync(message);
          }
          catch (Exception exception)
          {
              throw;
          }
      }
  }
  

• 异常追踪：

  • EasyNetQ会自动把异常跑到一个默认的错误队列：EasyNetQ_Default_Error_Queue，算是消息队列的Log，可以分析报错。

  • 同时可以开启Rabbit的Trace功能，就可以自动生成log文件，可以到management-admin-trace追踪记录，调试Bug：

    • 开启：rabbitmq rabbitmq-plugins enable rabbitmq_tracing

      ​ rabbitmq rabbitmqctl trace_on

    • 关闭：rabbitmq rabbitmq-plugins disable rabbitmq_tracing

      ​ rabbitmq rabbitmqctl trace_off