ABP vNext系列文章10---分布式事务集成netcore.Cap

最近项目中要用到分布式事务功能，调研了DTM和Cap,最终确定用Cap来实现，Cap支持最终一致性，项目中采用MQ作为消息中间件，数据库用的mysql，集成步骤如下：

1、在需要发布消息的服务中引入如下的包，我是放在了api层

    <PackageReference Include="DotNetCore.CAP" Version="5.2.0" />
    <PackageReference Include="DotNetCore.CAP.Dashboard" Version="5.2.0" />
    <PackageReference Include="DotNetCore.CAP.MySql" Version="5.2.0" />
    <PackageReference Include="DotNetCore.CAP.RabbitMQ" Version="5.2.0" />

2、编写Cap扩展服务

public static class CapExtensions
    {
        public static void AddMyCap(this IServiceCollection services, IConfiguration configuration)
        {

            services.AddCap(
                a => {
                    a.UseEntityFramework<QualificationDbContext>();
                    a.UseMySql(configuration.GetConnectionString("Default"));
                    //仅用于测试，正式使用后要换成可配置项
                    a.UseRabbitMQ(rb =>
                    {
                        rb.HostName = "118.111.111.111";
                        rb.UserName = "root";
                        rb.Password = "123456";
                        rb.Port = 5672;
                        rb.VirtualHost = "/";
                       
                    });

                    // 添加cap后台监控页面(人工处理)；页面地址为“/cap”；如：http://www.site.com/cap
                    a.UseDashboard();
                    // 配置定时器重试策略
                    a.FailedRetryInterval = 10; //重试间隔时间（秒），使用默认的就可以，可不用配置
                    a.FailedRetryCount = 5; //重试次数

                }
                );
            services.AddDbContext<QualificationDbContext>();
        }
    }

3、在配置文件中增加服务

 context.Services.AddMyCap(configuration);

4、在控制器中注册ICapPublisher类就可以发布消息了

namespace Qualification.Controllers
{
    [Route("api/Test")]

    public class TestController : AbpController
    {
        private readonly ICapPublisher capPublisher;
        public TestController(ICapPublisher _capPublisher)
        {
            this.capPublisher = _capPublisher;
        }
        /// <summary>
        /// 测试cap功能：创建证照时发布消息，在服务平台进行订阅
        /// </summary>
        /// <returns></returns>
        [HttpPost("CreateQualification")]
        public async Task<IActionResult> CreateQualification()
        {
            try
            {
                this.capPublisher.Publish<CreateQualificationCapDto>("Qualification.Create.Success", new CreateQualificationCapDto { Name = "Qualification", Count = 10 });
                return Ok("创建产品证照成功");
            }
            catch (Exception ex)
            {

                throw;
            }

        }
    }

    public class CreateQualificationCapDto
        {
           public string Name { get; set; }
           public int Count { get; set; }
        }
}

3、在订阅的程序b中同样引用cap的依赖包

4、同样写Cap服务的扩展程序，和服务a是一样的，这里就不再重复了

5、在订阅服务类中继承ICapSubscribe，因为我是用的ABP框架，所以继承了ITransientDependency接口，为了是注入服务实体，如果你不是用这个框架，请在手动注入服务：services.AddSingleton<Controllers.CapSubscribeService>();否则，订阅不到数据。

public interface ICapSubscribeService
    {
        public void UpdateOrder(CreateQualificationCapDto createQualification);
    }

    public class CapSubscribeService : ICapSubscribeService, ICapSubscribe, ITransientDependency
    {
        [CapSubscribe("Qualification.Create.Success")]
        public void UpdateOrder(CreateQualificationCapDto createQualification)
        {
            var data = createQualification;
        }
    }

    public class CreateQualificationCapDto
    {
        public string Name { get; set; }
        public int Count { get; set; }
    }