Asp.net Core CAP Kafka 分布式消息队列
CAP 是一个基于 .NET Standard 的 C# 库，它是一种处理分布式事务的解决方案，同样具有 EventBus 的功能，它具有轻量级、易使用、高性能等特点。
参考中文官网
从这张图可以看到CAP主要是保证消息的一致性,没有事务回滚的操作,需要自己实现消息双向推送
我一开始以为实现分布式事务锁的机制,后来消息微服务用锁实现事务也不太合适
下面是我写的一个Demo
CAP 支持的多种消息队列,我这里用的是kafka
1.kafka 安装,localtime是时区文件,可以进入bash设置中国的时区然后把文件拷贝出来,如果有中国时区的linux的系统直接copy出来映射就行了
docker pull wurstmeister/zookeeper
docker pull wurstmeister/kafka
docker run -d --name zookeeper -p 2181:2181 `
-v $pwd/localtime:/etc/localtime wurstmeister/zookeeper
docker run -d --name kafka `
-p 9092:9092 -e KAFKA_BROKER_ID=0 `
-e KAFKA_ZOOKEEPER_CONNECT=56.1.136.150:2181/kafka `
-e KAFKA_ADVERTISED_LISTENERS=PLAINTEXT://127.0.0.1:9092 `
-e KAFKA_LISTENERS=PLAINTEXT://0.0.0.0:9092 `
-v $pwd/localtime:/etc/localtime wurstmeister/kafka
2.新建项目 Services_1和Services_2
导包
Install-Package DotNetCore.CAP
Install-Package DotNetCore.CAP.Kafka
Install-Package DotNetCore.CAP.SqlServer
3.注册服务 Services_1和Services_2
services.AddCapExtension(Configuration);
public static class ServiceCollectionExtensions
{
public static void AddCapExtension(this IServiceCollection services, IConfiguration configuration)
{
services.AddCap(t =>
{
t.UseSqlServer(configuration.GetConnectionString("Cap"));
t.UseKafka(configuration.GetConnectionString("Kafka"));
});
}
}
- 消息订阅 Services_2
public interface ISubscriberEvent
{
public void Hello(string msg);
}
public class SubscriberEventHandler : ISubscriberEvent, ICapSubscribe
{
[CapSubscribe("Service2.hello")]
public void Hello(string msg)
{
Console.WriteLine(msg);
}
}
services.AddTransient<EventSubs.ISubscriberEvent, EventSubs.SubscriberEventHandler>();
5.消息发布
public class Service1Controller : ControllerBase
{
[HttpGet]
public IActionResult Get([FromServices] ICapPublisher capPublish, [FromServices] IConfiguration configuration)
{
using SqlConnection connection = new SqlConnection(configuration.GetConnectionString("Cap"));
connection.Open();
using (IDbTransaction transaction = connection.BeginTransaction(capPublish)) {
try
{
capPublish.Publish("Service2.hello", "分布式事务");
transaction.Commit();
}
catch (Exception ex)
{
transaction.Rollback();
}
}
return Ok();
}
}
