.net core使用EasyNetQ做EventBus

       随着SOA、微服务、CQRS的盛行,EventBus越来越流行,上GitHub搜了一下,还是有蛮多的这类实现,老牌的有NServiceBus(收费)、MassTransit,最近的有CAP(国人写的,1.4k个Star,非常不错)、ReBus(张队长在NanoFabric中推荐的)、RawRabbit等,今天我介绍的是另外一款产品:EasyNetQ,支持.net core,正如其名,用起来确实very easy。

       首先在asp.net core项目中添加EasyNetQ的nuget引用,注入:

public void ConfigureServices(IServiceCollection services)
{
       string rabbitMqConnection = Configuration["RabbitMqConnection"];
       services.AddSingleton(RabbitHutch.CreateBus(rabbitMqConnection));
}

       1、发布消息:

public class ValuesController : Controller
    {
        private IBus _bus;
        public ValuesController(IBus bus)
        {
            _bus = bus;
        }


        // POST api/values
        [HttpPost]
        public async Task Post([FromBody]Order message)
        {
            await _bus.PublishAsync(message);
        }
    }

          可自定义消息的Exchange和Queue,需要修改消息实体:

    [Queue("Qka.Order", ExchangeName = "Qka.Order")]
    public class Order
    {
        public int OrderId { get; set; }
    }

 

          2、订阅消息

   我们订阅的服务也是寄宿在asp.net core程序中,首先定义消费者:

    public class OrderConsumer : IConsume<Order>
    {
        [AutoSubscriberConsumer(SubscriptionId = "OrderService")]
        public void Consume(Order message)
        {
            //业务代码
        }
    }

          也可以使用异步方法:  

    public class OrderConsumer : IConsumeAsync<Order>
    {
        [AutoSubscriberConsumer(SubscriptionId = "OrderService")]
        public Task ConsumeAsync(Order message)
        {
            //业务代码
        }
    }

         利用EasyNetQ的自动订阅者进行订阅,这里扩展IApplicationBuilder:

public static class ApplicationExtenssion
{
        public static IApplicationBuilder UseSubscribe(this IApplicationBuilder appBuilder, string subscriptionIdPrefix, Assembly assembly)
        {
            var services = appBuilder.ApplicationServices.CreateScope().ServiceProvider;

            var lifeTime = services.GetService<IApplicationLifetime>();
            var bus = services.GetService<IBus>();
            lifeTime.ApplicationStarted.Register(() =>
            {
                var subscriber = new AutoSubscriber(bus, subscriptionIdPrefix);
                subscriber.Subscribe(assembly);         
subscriber.SubscribeAsync(assembly);
});

        lifeTime.ApplicationStopped.Register(()
=> { bus.Dispose(); });

        return appBuilder;
     }
}

          使用扩展方法:

        public void Configure(IApplicationBuilder app, IHostingEnvironment env)
        {
            app.UseSubscribe("OrderService", Assembly.GetExecutingAssembly());
        }

 

posted @ 2018-06-01 12:26 focus-lei 阅读(...) 评论(...) 编辑 收藏