Dapr牽手.NET學習筆記：釋出-訂閱
阿新 • • 發佈：2022-04-19
queue，是很好的削峰填谷工具，在業內也是主流；釋出訂閱，可以有效的解耦兩個應用，所以dapr把他們進行了有效的封裝，我們使用起來更簡單高效。
本篇的案例是下完訂單後，會把訊息釋出到redis（當然也可以是其他）中，通知系統和支付系統會訂單這個訊息，同時，通知系統和支付系統的兩個例項中，只會有一個例項接收到這個訊息，進行處理，呼叫示意圖如下：
專案結構如下：
一、配置
用docker-compose部署，docker-compose.yml內容
version: '3.4'
services:
#┌────────────────────────────────┐
#│ ordersystem app
pubsub.yaml（在components資料夾下 ）內容是預設，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: ""
訂閱配置檔案如下subscription.yaml（在components資料夾下 ）
apiVersion: dapr.io/v1alpha1
kind: Subscription
metadata:
name: myevent-subscription
spec:
topic: orderComplete
route: /ordercomplete
pubsubname: pubsub
scopes:
- pay
- notice
二、程式碼
OrderSystem專案的appsettings.json
"PublishUrl": "http://localhost:3500/v1.0/publish/pubsub/orderComplete"
OrderSystem專案的釋出方法
[HttpGet("/orderpub/{orderno}")]
public async Task<IActionResult> OrderPub(string orderno)
{
try
{
_logger.LogInformation($"Order,publish");
await Task.Delay(400);
var client = _clientFactory.CreateClient();
var stringContent = new StringContent(Newtonsoft.Json.JsonConvert.SerializeObject(new { OrderNo = orderno, Amount = 30000, OrderTime = DateTime.UtcNow}), System.Text.Encoding.UTF8, "application/json");
_logger.LogInformation(stringContent.ToString());
var content = await client.PostAsync(_publishUrl, stringContent);
return new JsonResult(new { order_result = "Order success,and publish", pay_result = content });
}
catch (Exception exc)
{
_logger.LogCritical(exc, exc.Message);
return new JsonResult(new { order_result = "Order success,and publish,pay exception", message = exc.Message });
}
}
PaymentSystem和NoticeSystem專案中的訂閱實現
兩個實體類
public class PubBody
{
public string id { get; set; }
public string source { get; set; }
public string pubsubname { get; set; }
public string traceid { get; set; }
public PubOrder data { get; set; }
public string specversion { get; set; }
public string datacontenttype { get; set; }
public string type { get; set; }
public string topic { get; set; }
}
public class PubOrder
{
public string OrderNo { get; set; }
public decimal Amount { get; set; }
public DateTime OrderTime { get; set; }
}
NoticeSystem和PaymentSystem兩個專案中的訂閱方法如下
[HttpPost("/ordercomplete")]
public async Task<IActionResult> OrderComplete()
{
try
{
_logger.LogInformation("PaymentSystem OrderComplete runing……");
using var reader = new StreamReader(Request.Body, System.Text.Encoding.UTF8);
var content = await reader.ReadToEndAsync();
var pubBody = Newtonsoft.Json.JsonConvert.DeserializeObject<PubBody>(content);
_logger.LogInformation($"--------- 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、釋出測試
進入在B2C目發，用命令列啟動docker compose
docker-compose up -d
可以測試了，呼叫OrderSystem的對外地址，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
檢視容器noticesystem1
檢視容器noticesystem2
檢視容器paymentsystem1
檢視容器paymentsystem2
NoticeSystem和PaymentSystem同時訂閱OrderSystem專案的釋出orderComplete，兩個例項會輪詢處理訂閱結果。Dapr就這樣，把複雜的釋出訂閱，封裝成一個api一樣的簡單呼叫和接收，專案中沒有一點的痕跡。