queue，是很好的削峰填谷工具，在業(yè)內(nèi)也是主流；發(fā)布訂閱，可以有效的解耦兩個(gè)應(yīng)用，所以dapr把他們進(jìn)行了有效的封裝，我們使用起來更簡(jiǎn)單高效。

本篇的案例是下完訂單后，會(huì)把消息發(fā)布到redis（當(dāng)然也可以是其他）中，通知系統(tǒng)和支付系統(tǒng)會(huì)訂單這個(gè)消息，同時(shí)，通知系統(tǒng)和支付系統(tǒng)的兩個(gè)實(shí)例中，只會(huì)有一個(gè)實(shí)例接收到這個(gè)消息，進(jìn)行處理，調(diào)用示意圖如下：

項(xiàng)目結(jié)構(gòu)如下：

一、配置

用docker-compose部署，docker-compose.yml內(nèi)容

version:?'3.4'services:#┌────────────────────────────────┐#│ ordersystem app + Dapr sidecar │#└────────────────────────────────┘o(jì)rdersystem:image: ${DOCKER_REGISTRY-}ordersystemdepends_on:- redis- placementbuild: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-}paymentsystembuild: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-}paymentsystembuild: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-}noticesystembuild: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-}noticesystembuild: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 networks:b2c-dapr:

pubsub.yaml（在components文件夾下?）內(nèi)容是默認(rèn)，如下

apiVersion: dapr.io/v1alpha1 kind: Component metadata:name: pubsub spec:type: pubsub.redisversion: v1metadata:- name: redisHostvalue: redis:6379- name: redisPasswordvalue: ""

訂閱配置文件如下subscription.yaml（在components文件夾下?）

apiVersion: dapr.io/v1alpha1 kind: Subscription metadata:name: myevent-subscription spec:topic: orderCompleteroute: /ordercompletepubsubname: pubsub scopes: - pay - notice

二、代碼

OrderSystem項(xiàng)目的appsettings.json

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

OrderSystem項(xiàng)目的發(fā)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項(xiàng)目中的訂閱實(shí)現(xiàn)

兩個(gè)實(shí)體類

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兩個(gè)項(xiàng)目中的訂閱方法如下

[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、發(fā)布測(cè)試

進(jìn)入在B2C目發(fā)，用命令行啟動(dòng)docker compose

docker-compose?up?-d

可以測(cè)試了，調(diào)用OrderSystem的對(duì)外地址，下訂單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

查看容器noticesystem2

查看容器paymentsystem1

查看容器paymentsystem2

NoticeSystem和PaymentSystem同時(shí)訂閱OrderSystem項(xiàng)目的發(fā)布o(jì)rderComplete，兩個(gè)實(shí)例會(huì)輪詢處理訂閱結(jié)果。Dapr就這樣，把復(fù)雜的發(fā)布訂閱，封裝成一個(gè)api一樣的簡(jiǎn)單調(diào)用和接收，項(xiàng)目中沒有一點(diǎn)的痕跡。

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