绑定有点像订阅发布，但又不一样，绑定更简单，绑定输出（调用方）-绑定输入（被调用方）。
本例是用docker compose编排，并且用rabbitMQ来支持，因为rabbitMQ支持输入和输出绑定。
demo的目录结构：
binding.yaml，放在components目录下
apiVersion: dapr.io/v1alpha1
kind: Component
metadata:name: orderupdate
spec:type: bindings.rabbitmqversion: v1metadata:- name: queueNamevalue: bindQueue- name: hostvalue: amqp://admin:!2021que@rabbitmq:5672- name: durablevalue: true- name: deleteWhenUnusedvalue: false- name: ttlInSecondsvalue: 60- name: prefetchCountvalue: 0- name: exclusivevalue: false- name: maxPriorityvalue: 5B2C目录中的docker-compose.yml
version: '3.4'services:#┌────────────────────────────────┐#│ ordersystem app + Dapr sidecar │#└────────────────────────────────┘ordersystem:image: ${DOCKER_REGISTRY-}ordersystemdepends_on:- redis- placement build:context: ../dockerfile: OrderSystem/Dockerfileports:- "3500:3500"volumes: - ../OrderSystem:/OrderSystem networks:- b2c-daprordersystem-dapr:image: "daprio/daprd:latest"command: [ "./daprd", "-app-id", "order", "-app-port", "80","-placement-host-address", "placement:50006","-components-path","/components"]depends_on:- ordersystemnetwork_mode: "service:ordersystem"volumes: - ../components:/components #┌───────────────────────────────────┐#│ paymentsystem1 app + Dapr sidecar │#└───────────────────────────────────┘ paymentsystem1:image: ${DOCKER_REGISTRY-}paymentsystemdepends_on:- redis- placement - rabbitmq build:context: ../dockerfile: PaymentSystem/Dockerfileports:- "3601:3500"volumes: - ../PaymentSystem:/PaymentSystem networks:- b2c-dapr paymentsystem1-dapr:image: "daprio/daprd:latest"command: [ "./daprd", "-app-id", "pay", "-app-port", "80","-placement-host-address", "placement:50006","-components-path","/components" ]depends_on:- paymentsystem1network_mode: "service:paymentsystem1"volumes: - ../components:/components #┌───────────────────────────────────┐#│ paymentsystem2 app + Dapr sidecar │#└───────────────────────────────────┘ paymentsystem2:image: ${DOCKER_REGISTRY-}paymentsystemdepends_on:- redis- placement - rabbitmq build:context: ../dockerfile: PaymentSystem/Dockerfilevolumes: - ../PaymentSystem:/PaymentSystem ports:- "3602:3500"networks:- b2c-dapr paymentsystem2-dapr:image: "daprio/daprd:latest"command: [ "./daprd", "-app-id", "pay", "-app-port", "80" ,"-placement-host-address", "placement:50006","-components-path","/components"]depends_on:- paymentsystem2network_mode: "service:paymentsystem2"volumes: - ../components:/components #┌───────────────────────────────────┐#│ noticesystem1 app + Dapr sidecar │#└───────────────────────────────────┘ noticesystem1:image: ${DOCKER_REGISTRY-}noticesystemdepends_on:- redis- placement - rabbitmq build:context: ../dockerfile: NoticeSystem/Dockerfileports:- "3701:3500"volumes: - ../NoticeSystem:/NoticeSystem networks:- b2c-dapr noticesystem1-dapr:image: "daprio/daprd:latest"command: [ "./daprd", "-app-id", "notice", "-app-port", "80","-placement-host-address", "placement:50006","-components-path","/components" ]depends_on:- noticesystem1network_mode: "service:noticesystem1"volumes: - ../components:/components #┌───────────────────────────────────┐#│ noticesystem2 app + Dapr sidecar │#└───────────────────────────────────┘ noticesystem2:image: ${DOCKER_REGISTRY-}noticesystemdepends_on:- redis- placement - rabbitmq build:context: ../dockerfile: NoticeSystem/Dockerfileports:- "3702:3500"volumes: - ../NoticeSystem:/NoticeSystem networks:- b2c-dapr noticesystem2-dapr:image: "daprio/daprd:latest"command: [ "./daprd", "-app-id", "notice", "-app-port", "80","-placement-host-address", "placement:50006","-components-path","/components" ]depends_on:- noticesystem2network_mode: "service:noticesystem2"volumes: - ../components:/components #┌────────────────────────┐#│ Dapr placement service │#└────────────────────────┘ placement:image: "daprio/dapr"command: ["./placement", "-port", "50006"]ports:- "50006:50006"networks:- b2c-dapr#┌───────────────────┐#│ Redis state store │#└───────────────────┘ redis:image: "redis:latest"ports:- "6380:6379"networks:- b2c-dapr#┌──────────────────────┐#│ RabbitMQ state store │#└──────────────────────┘ rabbitmq:image: "rabbitmq:management"ports:- "15672:15672"- "5672:5672" environment:- RABBITMQ_DEFAULT_USER=admin- RABBITMQ_DEFAULT_PASS=!2021que networks:- b2c-dapr networks:b2c-dapr:在PaymentSystem和NoticeSystem添加监听传入的事件
[HttpPost("/orderupdate")]
public async Task<IActionResult> OrderUpdate()
{_logger.LogInformation("NoticeSystem OrderUpdate……");using var reader = new StreamReader(Request.Body, System.Text.Encoding.UTF8);var content = await reader.ReadToEndAsync();_logger.LogInformation(content);return Ok();
}启动 docker-compose up -d
会发现所有的挎斗都失败，如下图：
查看日志，发现是rabbitMQ的5672没有连接成功，
绑过一段分析，配置和代码都没有问题 ，问题 出现在时差上，虽然在docker-compose中，配置了所有服务依赖rabbitMQ，但rabbitMQ的容器虽然启动了，但rabbitMQ服务还没有完全启动起来，这个时间挎斗连接时，就发生连接错误，可以等上一会，手动再次启动挎斗容器就可以了。（这块在生产上需要解决，不能每次都手动）
服务都启动后，可以测试了，调用绑定
http://localhost:3601/v1.0/bindings/orderupdate
需要用post一个json，来调用绑定，分别post了包含10个1 ，10个2，10个3，10个4的四个请求，四个请求会分别触发四个服务的orderupdate事件（这里orderupdate业务不太适合用绑定，应该用发布订阅，因为一个订单变是多，PaymentSystem和NoticeSystem都应该被通知到，但绑定事件不可以，这也是两者的区别）
