queue,是很好的削峰填谷工具,在业内也是主流;发布订阅,可以有效的解耦两个应用,所以dapr把他们进行了有效的封装,我们使用起来更简单高效。

  本篇的案例是下完订单后,会把消息发布到redis(当然也可以是其他)中,通知系统和支付系统会订单这个消息,同时,通知系统和支付系统的两个实例中,只会有一个实例接收到这个消息,进行处理,调用示意图如下:

Dapr牵手.NET学习笔记:发布-订阅_json

 项目结构如下:

Dapr牵手.NET学习笔记:发布-订阅_json_02


一、配置

用docker-compose部署,docker-compose.yml内容

version: '3.4'

services:
#┌────────────────────────────────┐
#│ ordersystem app + Dapr sidecar │
#└────────────────────────────────┘
ordersystem:
image: ${DOCKER_REGISTRY-}ordersystem
depends_on:
- redis
- placement
build:
context: ../
dockerfile: OrderSystem/Dockerfile
ports:
- "3500:3500"
volumes:
- ../OrderSystem:/OrderSystem
networks:
- b2c-dapr
ordersystem-dapr:
image: "daprio/daprd:latest"
command: [ "./daprd", "-app-id", "order", "-app-port", "80","-placement-host-address", "placement:50006","-components-path","/components"]
depends_on:
- ordersystem
network_mode: "service:ordersystem"
volumes:
- ../components:/components

#┌───────────────────────────────────┐
#│ paymentsystem1 app + Dapr sidecar │
#└───────────────────────────────────┘
paymentsystem1:
image: ${DOCKER_REGISTRY-}paymentsystem
build:
context: ../
dockerfile: PaymentSystem/Dockerfile
ports:
- "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:
- paymentsystem1
network_mode: "service:paymentsystem1"
volumes:
- ../components:/components

#┌───────────────────────────────────┐
#│ paymentsystem2 app + Dapr sidecar │
#└───────────────────────────────────┘
paymentsystem2:
image: ${DOCKER_REGISTRY-}paymentsystem
build:
context: ../
dockerfile: PaymentSystem/Dockerfile
volumes:
- ../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:
- paymentsystem2
network_mode: "service:paymentsystem2"
volumes:
- ../components:/components

#┌───────────────────────────────────┐
#│ noticesystem1 app + Dapr sidecar │
#└───────────────────────────────────┘
noticesystem1:
image: ${DOCKER_REGISTRY-}noticesystem
build:
context: ../
dockerfile: NoticeSystem/Dockerfile
ports:
- "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:
- noticesystem1
network_mode: "service:noticesystem1"
volumes:
- ../components:/components

#┌───────────────────────────────────┐
#│ noticesystem2 app + Dapr sidecar │
#└───────────────────────────────────┘
noticesystem2:
image: ${DOCKER_REGISTRY-}noticesystem
build:
context: ../
dockerfile: NoticeSystem/Dockerfile
ports:
- "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:
- noticesystem2
network_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
networks:
b2c-dapr:

pubsub.yaml(在components文件夹下 )内容是默认,如下

apiVersion: dapr.io/v1alpha1
kind: Component
metadata:
name: pubsub
spec:
type: pubsub.redis
version: v1
metadata:
- name: redisHost
value: redis:6379
- name: redisPassword
value: ""

订阅配置文件如下subscription.yaml(在components文件夹下 )

apiVersion: dapr.io/v1alpha1
kind: Subscription
metadata:
name: myevent-subscription
spec:
topic: orderComplete
route: /ordercomplete
pubsubname: pubsub
scopes:
- pay
- notice

二、代码

OrderSystem项目的appsettings.json

"PublishUrl": "http://localhost:3500/v1.0/publish/pubsub/orderComplete"

OrderSystem项目的发布方法

[HttpGet("/orderpub/{orderno}")]
public async Task<IActionResult> OrderPub(string orderno)
{
try
{
_logger.LogInformation($"Order,publish");
await Task.Delay(400);
var client = _clientFactory.CreateClient();

var stringContent = new StringContent(Newtonsoft.Json.JsonConvert.SerializeObject(new { OrderNo = orderno, Amount = 30000, OrderTime = DateTime.UtcNow}), System.Text.Encoding.UTF8, "application/json");
_logger.LogInformation(stringContent.ToString());
var content = await client.PostAsync(_publishUrl, stringContent);
return new JsonResult(new { order_result = "Order success,and publish", pay_result = content });
}
catch (Exception exc)
{
_logger.LogCritical(exc, exc.Message);
return new JsonResult(new { order_result = "Order success,and publish,pay exception", message = exc.Message });
}
}

PaymentSystem和NoticeSystem项目中的订阅实现

两个实体类

public class PubBody
{
public string id { get; set; }
public string source { get; set; }
public string pubsubname { get; set; }
public string traceid { get; set; }
public PubOrder data { get; set; }
public string specversion { get; set; }
public string datacontenttype { get; set; }
public string type { get; set; }
public string topic { get; set; }
}

public class PubOrder
{
public string OrderNo { get; set; }
public decimal Amount { get; set; }
public DateTime OrderTime { get; set; }
}

NoticeSystem和PaymentSystem两个项目中的订阅方法如下

[HttpPost("/ordercomplete")]
public async Task<IActionResult> OrderComplete()
{
try
{
_logger.LogInformation("PaymentSystem OrderComplete runing……");
using var reader = new StreamReader(Request.Body, System.Text.Encoding.UTF8);
var content = await reader.ReadToEndAsync();
var pubBody = Newtonsoft.Json.JsonConvert.DeserializeObject<PubBody>(content);
_logger.LogInformation($"--------- HostName:{Dns.GetHostName()},OrderNo:{pubBody?.data.OrderNo},OrderAmount:{pubBody?.data.Amount},OrderTime:{pubBody?.data.OrderTime} -----------");
await Task.Delay(200);
_logger.LogInformation($"subscription pay complete");
_logger.LogInformation($"return SUCCESS");
return new JsonResult(new
{
Status = "SUCCESS"
});
}
catch (Exception exc)
{
_logger.LogCritical(exc, exc.Message);
_logger.LogInformation($"return RETRY");
return new JsonResult(new
{
Status = "RETRY"
});
}
}

三、发布测试

进入在B2C目发,用命令行启动docker compose

docker-compose up -d

可以测试了,调用OrderSystem的对外地址,下订单NO0001,和NO0002

localhost:3500/v1.0/invoke/order/method/orderpub/NO0001和

localhost:3500/v1.0/invoke/order/method/orderpub/NO0001

查看容器noticesystem1

Dapr牵手.NET学习笔记:发布-订阅_docker_03

 查看容器noticesystem2

Dapr牵手.NET学习笔记:发布-订阅_json_04

 查看容器paymentsystem1

Dapr牵手.NET学习笔记:发布-订阅_docker_05

 查看容器paymentsystem2

Dapr牵手.NET学习笔记:发布-订阅_redis_06

   NoticeSystem和PaymentSystem同时订阅OrderSystem项目的发布orderComplete,两个实例会轮询处理订阅结果。Dapr就这样,把复杂的发布订阅,封装成一个api一样的简单调用和接收,项目中没有一点的痕迹。

  想要更快更方便的了解相关知识,可以关注微信公众号

Dapr牵手.NET学习笔记:发布-订阅_json_07