Dapr + .NET Core實戰（二） 服務調用

原創 伊辛伊憶 2021-09-24 13:10

服務調用是什麼

 

在分佈式應用程序中的服務之間進行調用會涉及到許多挑戰。 例如：

  • 維護其他服務的地址。
  • 如何安全地調用服務。
  • 在發生短暫的 暫時性錯誤 時如何處理重試。
  • 分佈式應用程序調用鏈路追蹤。

服務調用構建塊通過使用 Dapr 挎鬥作爲服務的 反向代理 來解決這些難題。

 

工作原理

 

 

由於調用經過Sidecar，Dapr 可以注入一些有其他行爲：

  • 失敗時自動重試調用。
  • 通過相互 (mTLS) 身份驗證（包括自動證書滾動更新），在服務之間進行調用。
  • 使用訪問控制策略控制客戶端可以執行的操作。
  • 捕獲服務間所有調用的跟蹤和指標，以提供分佈式調用鏈路追蹤與診斷。

 

任何應用程序都可以通過使用 Dapr 中內置的本機 Invoke API 來調用 Dapr Sidecar。 可以通過 HTTP 或 gRPC 調用 API。 使用以下 URL 調用 HTTP API：

http://localhost:<dapr-port>/v1.0/invoke/<application-id>/method/<method-name>
  • <dapr-port> Dapr 正在偵聽的 HTTP 端口。
  • <application-id> 要調用的服務的應用程序 ID。
  • <method-name> 要在遠程服務上調用的方法的名稱。

項目演示

我們使用.NET5創建兩個WebAPI項目：BackEnd和FrontEnd，通過FrontEnd調用BackEnd

 

 

指定BackEnd默認啓動端口5000

        public static IHostBuilder CreateHostBuilder(string[] args) =>
            Host.CreateDefaultBuilder(args)
                .ConfigureWebHostDefaults(webBuilder =>
                {
                    webBuilder.UseStartup<Startup>().UseUrls("http://*:5000");
                });

 

通過Dapr CLI啓動BackEnd，指定sidecar端口爲3511，默認爲3500，指定app-port是5000，與BackEnd默認端口保持一致

dapr run --dapr-http-port 3511 --app-port 5000 --app-id backend dotnet  .\BackEnd\bin\Debug\net5.0\BackEnd.dll
C:\demo\test\DaprBackEnd>dapr run --dapr-http-port 3511 --app-port 5000 --app-id backend dotnet  .\BackEnd\bin\Debug\net5.0\BackEnd.dll
Starting Dapr with id backend. HTTP Port: 3511. gRPC Port: 30204
time="2021-09-23T14:14:08.3785429+08:00" level=info msg="starting Dapr Runtime -- version 1.4.0 -- commit ed969edc72b3934fffb481f079b736f3588e373a" app_id=backend instance=chesterchen-lap scope=dapr.runtime type=log ver=1.4.0
time="2021-09-23T14:14:08.3831089+08:00" level=info msg="log level set to: info" app_id=backend instance=chesterchen-lap scope=dapr.runtime type=log ver=1.4.0
time="2021-09-23T14:14:08.3831089+08:00" level=info msg="metrics server started on :30205/" app_id=backend instance=chesterchen-lap scope=dapr.metrics type=log ver=1.4.0
time="2021-09-23T14:14:08.3861203+08:00" level=info msg="standalone mode configured" app_id=backend instance=chesterchen-lap scope=dapr.runtime type=log ver=1.4.0
time="2021-09-23T14:14:08.3861203+08:00" level=info msg="app id: backend" app_id=backend instance=chesterchen-lap scope=dapr.runtime type=log ver=1.4.0
time="2021-09-23T14:14:08.3871107+08:00" level=info msg="mTLS is disabled. Skipping certificate request and tls validation" app_id=backend instance=chesterchen-lap scope=dapr.runtime type=log ver=1.4.0
time="2021-09-23T14:14:08.4115681+08:00" level=info msg="local service entry announced: backend -> 10.32.193.9:30209" app_id=backend instance=chesterchen-lap scope=dapr.contrib type=log ver=1.4.0
time="2021-09-23T14:14:08.4115681+08:00" level=info msg="Initialized name resolution to mdns" app_id=backend instance=chesterchen-lap scope=dapr.runtime type=log ver=1.4.0
time="2021-09-23T14:14:08.4127024+08:00" level=info msg="loading components" app_id=backend instance=chesterchen-lap scope=dapr.runtime type=log ver=1.4.0
time="2021-09-23T14:14:08.4160224+08:00" level=info msg="component loaded. name: pubsub, type: pubsub.redis/v1" app_id=backend instance=chesterchen-lap scope=dapr.runtime type=log ver=1.4.0
time="2021-09-23T14:14:08.4160224+08:00" level=info msg="waiting for all outstanding components to be processed" app_id=backend instance=chesterchen-lap scope=dapr.runtime type=log ver=1.4.0
time="2021-09-23T14:14:08.4187042+08:00" level=info msg="component loaded. name: statestore, type: state.redis/v1" app_id=backend instance=chesterchen-lap scope=dapr.runtime type=log ver=1.4.0
time="2021-09-23T14:14:08.4187042+08:00" level=info msg="all outstanding components processed" app_id=backend instance=chesterchen-lap scope=dapr.runtime type=log ver=1.4.0
time="2021-09-23T14:14:08.4192486+08:00" level=info msg="enabled gRPC tracing middleware" app_id=backend instance=chesterchen-lap scope=dapr.runtime.grpc.api type=log ver=1.4.0
time="2021-09-23T14:14:08.4192486+08:00" level=info msg="enabled gRPC metrics middleware" app_id=backend instance=chesterchen-lap scope=dapr.runtime.grpc.api type=log ver=1.4.0
time="2021-09-23T14:14:08.4192486+08:00" level=info msg="API gRPC server is running on port 30204" app_id=backend instance=chesterchen-lap scope=dapr.runtime type=log ver=1.4.0
time="2021-09-23T14:14:08.4197888+08:00" level=info msg="enabled metrics http middleware" app_id=backend instance=chesterchen-lap scope=dapr.runtime.http type=log ver=1.4.0
time="2021-09-23T14:14:08.4197888+08:00" level=info msg="enabled tracing http middleware" app_id=backend instance=chesterchen-lap scope=dapr.runtime.http type=log ver=1.4.0
time="2021-09-23T14:14:08.4202954+08:00" level=info msg="http server is running on port 3511" app_id=backend instance=chesterchen-lap scope=dapr.runtime type=log ver=1.4.0
time="2021-09-23T14:14:08.420335+08:00" level=info msg="The request body size parameter is: 4" app_id=backend instance=chesterchen-lap scope=dapr.runtime type=log ver=1.4.0
time="2021-09-23T14:14:08.420335+08:00" level=info msg="enabled gRPC tracing middleware" app_id=backend instance=chesterchen-lap scope=dapr.runtime.grpc.internal type=log ver=1.4.0
time="2021-09-23T14:14:08.4225403+08:00" level=info msg="enabled gRPC metrics middleware" app_id=backend instance=chesterchen-lap scope=dapr.runtime.grpc.internal type=log ver=1.4.0
time="2021-09-23T14:14:08.4230868+08:00" level=info msg="internal gRPC server is running on port 30209" app_id=backend instance=chesterchen-lap scope=dapr.runtime type=log ver=1.4.0
time="2021-09-23T14:14:08.4230868+08:00" level=info msg="application protocol: http. waiting on port 5000.  This will block until the app is listening on that port." app_id=backend instance=chesterchen-lap scope=dapr.runtime type=log ver=1.4.0
== APP == info: Microsoft.Hosting.Lifetime[0]
== APP ==       Now listening on: http://[::]:5000
== APP == info: Microsoft.Hosting.Lifetime[0]
== APP ==       Application started. Press Ctrl+C to shut down.
== APP == info: Microsoft.Hosting.Lifetime[0]
== APP ==       Hosting environment: Production
== APP == info: Microsoft.Hosting.Lifetime[0]
== APP ==       Content root path: C:\demo\test\DaprBackEnd
time="2021-09-23T14:14:08.7252681+08:00" level=info msg="application discovered on port 5000" app_id=backend instance=chesterchen-lap scope=dapr.runtime type=log ver=1.4.0
== APP == info: Microsoft.AspNetCore.Hosting.Diagnostics[1]
== APP ==       Request starting HTTP/1.1 GET http://127.0.0.1:5000/dapr/config application/json -
== APP == info: Microsoft.AspNetCore.Hosting.Diagnostics[2]
== APP ==       Request finished HTTP/1.1 GET http://127.0.0.1:5000/dapr/config application/json - - 404 0 - 17.3850ms
time="2021-09-23T14:14:08.7693649+08:00" level=info msg="application configuration loaded" app_id=backend instance=chesterchen-lap scope=dapr.runtime type=log ver=1.4.0
time="2021-09-23T14:14:08.7699003+08:00" level=info msg="actor runtime started. actor idle timeout: 1h0m0s. actor scan interval: 30s" app_id=backend instance=chesterchen-lap scope=dapr.runtime.actor type=log ver=1.4.0
== APP == info: Microsoft.AspNetCore.Hosting.Diagnostics[1]
== APP ==       Request starting HTTP/1.1 GET http://127.0.0.1:5000/dapr/subscribe application/json -
== APP == info: Microsoft.AspNetCore.Hosting.Diagnostics[2]
time="2021-09-23T14:14:08.7736383+08:00" level=info msg="dapr initialized. Status: Running. Init Elapsed 387.518ms" app_id=backend instance=chesterchen-lap scope=dapr.runtime type=log ver=1.4.0
== APP ==       Request finished HTTP/1.1 GET http://127.0.0.1:5000/dapr/subscribe application/json - - 404 0 - 0.1789ms
time="2021-09-23T14:14:08.7888444+08:00" level=info msg="placement tables updated, version: 0" app_id=backend instance=chesterchen-lap scope=dapr.runtime.actor.internal.placement type=log ver=1.4.0
Updating metadata for app command: dotnet .\BackEnd\bin\Debug\net5.0\BackEnd.dll
You're up and running! Both Dapr and your app logs will appear here.

 

現在修改FrontEnd裏Demo，指定啓動端口5001

        public static IHostBuilder CreateHostBuilder(string[] args) =>
            Host.CreateDefaultBuilder(args)
                .ConfigureWebHostDefaults(webBuilder =>
                {
                    webBuilder.UseStartup<Startup>().UseUrls("http://*:5001");
                });

 

引入Nuget包 Dapr.Client，新建DaprController

 

 

 

1.使用 HttpClient調用HTTP服務

using Dapr.Client;

using Microsoft.AspNetCore.Mvc;
using Microsoft.Extensions.Logging;

using System.Collections.Generic;
using System.Net.Http;
using System.Threading.Tasks;

namespace FrontEnd.Controllers
{
    [ApiController]
    [Route("[controller]")]
    public class DaprController : ControllerBase
    {

        private readonly ILogger<DaprController> _logger;

        public DaprController(ILogger<DaprController> logger)
        {
            _logger = logger;
        }

        // 通過HttpClient調用BackEnd
        [HttpGet]
        public async Task<ActionResult> GetAsync()
        {
            using var httpClient = DaprClient.CreateInvokeHttpClient();
            var result = await httpClient.GetAsync("http://backend/WeatherForecast");
            var resultContent = string.Format("result is {0} {1}", result.StatusCode, await result.Content.ReadAsStringAsync());
            return Ok(resultContent);
        }
    }
}

GetAsync API中通過DaprClient.CreateInvokeHttpClient()新建了HttpClient,通過GetAsync方法調用了backend服務中的WeatherForecastAPI。

Sidecar使用可插接式名稱解析組件來解析服務BackEnd的地址。在自承載模式下，Dapr 使用 mdn 來查找它。 在 Kubernetes 模式下運行時，Kubernetes DNS 服務將確定地址。

2.使用 DaprClient調用HTTP服務

        // 通過DaprClient調用BackEnd
        [HttpGet("get2")]
        public async Task<ActionResult> Get2Async()
        {
            using var daprClient = new DaprClientBuilder().Build();
            var result = await daprClient.InvokeMethodAsync<IEnumerable<WeatherForecast>>(HttpMethod.Get, "backend", "WeatherForecast");
            return Ok(result);
        }

DaprController中新增API Get2Async 

3.使用注入方式調用 DaprClient

首先引入Nuget包Dapr.AspNetCore，然後在Startup.cs注入Dapr

        public void ConfigureServices(IServiceCollection services)
        {
            services.AddControllers().AddDapr();
        }

新建DaprDIController

using Dapr.Client;

using Microsoft.AspNetCore.Mvc;
using Microsoft.Extensions.Logging;

using System.Collections.Generic;
using System.Net.Http;
using System.Threading.Tasks;

namespace FrontEnd.Controllers
{
    [Route("[controller]")]
    [ApiController]
    public class DaprDIController : ControllerBase
    {
        private readonly ILogger<DaprDIController> _logger;
        private readonly DaprClient _daprClient;
        public DaprDIController(ILogger<DaprDIController> logger, DaprClient daprClient)
        {
            _logger = logger;
            _daprClient = daprClient;
        }

        [HttpGet()]
        public async Task<ActionResult> GetAsync()
        {
            var result = await _daprClient.InvokeMethodAsync<IEnumerable<WeatherForecast>>(HttpMethod.Get, "backend", "WeatherForecast");
            return Ok(result);
        }
    }
}

以上代碼通過注入方式注入DaprClient

4.使用DaprClient同樣可以調用GRPC

await daprClient.InvokeMethodGrpcAsync<Order, OrderConfirmation>("orderservice", "submitOrder", order);

與HTTP調用方式一致，不再爲GRPC新建server

 

通過Dapr CLI啓動FrontEnd，指定sidecar端口爲3501，默認爲3500，指定app-port是5001，與FrontEnd默認端口保持一致

dapr run --dapr-http-port 3501 --app-port 5001  --app-id frontend dotnet  .\FrontEnd\bin\Debug\net5.0\FrontEnd.dll
C:\demo\test\DaprBackEnd>dapr run --dapr-http-port 3501 --app-port 5001  --app-id frontend dotnet  .\FrontEnd\bin\Debug\net5.0\FrontEnd.dll
Starting Dapr with id frontend. HTTP Port: 3501. gRPC Port: 1045
time="2021-09-23T14:15:24.5222236+08:00" level=info msg="starting Dapr Runtime -- version 1.4.0 -- commit ed969edc72b3934fffb481f079b736f3588e373a" app_id=frontend instance=chesterchen-lap scope=dapr.runtime type=log ver=1.4.0
time="2021-09-23T14:15:24.5269659+08:00" level=info msg="log level set to: info" app_id=frontend instance=chesterchen-lap scope=dapr.runtime type=log ver=1.4.0
time="2021-09-23T14:15:24.5269659+08:00" level=info msg="metrics server started on :1046/" app_id=frontend instance=chesterchen-lap scope=dapr.metrics type=log ver=1.4.0
time="2021-09-23T14:15:24.5302603+08:00" level=info msg="standalone mode configured" app_id=frontend instance=chesterchen-lap scope=dapr.runtime type=log ver=1.4.0
time="2021-09-23T14:15:24.5302904+08:00" level=info msg="app id: frontend" app_id=frontend instance=chesterchen-lap scope=dapr.runtime type=log ver=1.4.0
time="2021-09-23T14:15:24.5302904+08:00" level=info msg="mTLS is disabled. Skipping certificate request and tls validation" app_id=frontend instance=chesterchen-lap scope=dapr.runtime type=log ver=1.4.0
time="2021-09-23T14:15:24.559128+08:00" level=info msg="local service entry announced: frontend -> 10.32.193.9:1051" app_id=frontend instance=chesterchen-lap scope=dapr.contrib type=log ver=1.4.0
time="2021-09-23T14:15:24.559128+08:00" level=info msg="Initialized name resolution to mdns" app_id=frontend instance=chesterchen-lap scope=dapr.runtime type=log ver=1.4.0
time="2021-09-23T14:15:24.560108+08:00" level=info msg="loading components" app_id=frontend instance=chesterchen-lap scope=dapr.runtime type=log ver=1.4.0
time="2021-09-23T14:15:24.5641089+08:00" level=info msg="component loaded. name: pubsub, type: pubsub.redis/v1" app_id=frontend instance=chesterchen-lap scope=dapr.runtime type=log ver=1.4.0
time="2021-09-23T14:15:24.5641089+08:00" level=info msg="waiting for all outstanding components to be processed" app_id=frontend instance=chesterchen-lap scope=dapr.runtime type=log ver=1.4.0
time="2021-09-23T14:15:24.5671082+08:00" level=info msg="component loaded. name: statestore, type: state.redis/v1" app_id=frontend instance=chesterchen-lap scope=dapr.runtime type=log ver=1.4.0
time="2021-09-23T14:15:24.5671082+08:00" level=info msg="all outstanding components processed" app_id=frontend instance=chesterchen-lap scope=dapr.runtime type=log ver=1.4.0
time="2021-09-23T14:15:24.5671082+08:00" level=info msg="enabled gRPC tracing middleware" app_id=frontend instance=chesterchen-lap scope=dapr.runtime.grpc.api type=log ver=1.4.0
time="2021-09-23T14:15:24.5671082+08:00" level=info msg="enabled gRPC metrics middleware" app_id=frontend instance=chesterchen-lap scope=dapr.runtime.grpc.api type=log ver=1.4.0
time="2021-09-23T14:15:24.5671082+08:00" level=info msg="API gRPC server is running on port 1045" app_id=frontend instance=chesterchen-lap scope=dapr.runtime type=log ver=1.4.0
time="2021-09-23T14:15:24.5684039+08:00" level=info msg="enabled metrics http middleware" app_id=frontend instance=chesterchen-lap scope=dapr.runtime.http type=log ver=1.4.0
time="2021-09-23T14:15:24.5700491+08:00" level=info msg="enabled tracing http middleware" app_id=frontend instance=chesterchen-lap scope=dapr.runtime.http type=log ver=1.4.0
time="2021-09-23T14:15:24.5700491+08:00" level=info msg="http server is running on port 3501" app_id=frontend instance=chesterchen-lap scope=dapr.runtime type=log ver=1.4.0
time="2021-09-23T14:15:24.5705931+08:00" level=info msg="The request body size parameter is: 4" app_id=frontend instance=chesterchen-lap scope=dapr.runtime type=log ver=1.4.0
time="2021-09-23T14:15:24.5705931+08:00" level=info msg="enabled gRPC tracing middleware" app_id=frontend instance=chesterchen-lap scope=dapr.runtime.grpc.internal type=log ver=1.4.0
time="2021-09-23T14:15:24.5705931+08:00" level=info msg="enabled gRPC metrics middleware" app_id=frontend instance=chesterchen-lap scope=dapr.runtime.grpc.internal type=log ver=1.4.0
time="2021-09-23T14:15:24.5711294+08:00" level=info msg="internal gRPC server is running on port 1051" app_id=frontend instance=chesterchen-lap scope=dapr.runtime type=log ver=1.4.0
time="2021-09-23T14:15:24.5711294+08:00" level=info msg="application protocol: http. waiting on port 5001.  This will block until the app is listening on that port." app_id=frontend instance=chesterchen-lap scope=dapr.runtime type=log ver=1.4.0
== APP == info: Microsoft.Hosting.Lifetime[0]
== APP ==       Now listening on: http://[::]:5001
== APP == info: Microsoft.Hosting.Lifetime[0]
== APP ==       Application started. Press Ctrl+C to shut down.
== APP == info: Microsoft.Hosting.Lifetime[0]
== APP ==       Hosting environment: Production
== APP == info: Microsoft.Hosting.Lifetime[0]
== APP ==       Content root path: C:\demo\test\DaprBackEnd
time="2021-09-23T14:15:24.8729143+08:00" level=info msg="application discovered on port 5001" app_id=frontend instance=chesterchen-lap scope=dapr.runtime type=log ver=1.4.0
== APP == info: Microsoft.AspNetCore.Hosting.Diagnostics[1]
== APP ==       Request starting HTTP/1.1 GET http://127.0.0.1:5001/dapr/config application/json -
== APP == info: Microsoft.AspNetCore.Hosting.Diagnostics[2]
== APP ==       Request finished HTTP/1.1 GET http://127.0.0.1:5001/dapr/config application/json - - 404 0 - 19.0408ms
time="2021-09-23T14:15:24.9188354+08:00" level=info msg="application configuration loaded" app_id=frontend instance=chesterchen-lap scope=dapr.runtime type=log ver=1.4.0
time="2021-09-23T14:15:24.9193692+08:00" level=info msg="actor runtime started. actor idle timeout: 1h0m0s. actor scan interval: 30s" app_id=frontend instance=chesterchen-lap scope=dapr.runtime.actor type=log ver=1.4.0
== APP == info: Microsoft.AspNetCore.Hosting.Diagnostics[1]
== APP ==       Request starting HTTP/1.1 GET http://127.0.0.1:5001/dapr/subscribe application/json -
== APP == info: Microsoft.AspNetCore.Hosting.Diagnostics[2]
== APP ==       Request finished HTTP/1.1 GET http://127.0.0.1:5001/dapr/subscribe application/json - - 404 0 - 0.2000ms
time="2021-09-23T14:15:24.9236093+08:00" level=info msg="dapr initialized. Status: Running. Init Elapsed 393.349ms" app_id=frontend instance=chesterchen-lap scope=dapr.runtime type=log ver=1.4.0
time="2021-09-23T14:15:24.9393948+08:00" level=info msg="placement tables updated, version: 0" app_id=frontend instance=chesterchen-lap scope=dapr.runtime.actor.internal.placement type=log ver=1.4.0
Updating metadata for app command: dotnet .\FrontEnd\bin\Debug\net5.0\FrontEnd.dll
You're up and running! Both Dapr and your app logs will appear here.

  Dapr CLI查看運行中的app

dapr list
  APP ID    HTTP PORT  GRPC PORT  APP PORT  COMMAND               AGE  CREATED              PID
  backend   3511       1033       5000      dotnet .\BackEnd\...  9s   2021-09-24 09:25.17  860
  frontend  3501       1056       5001      dotnet .\FrontEnd...  7s   2021-09-24 09:25.19  5236

 

測試調用

1.瀏覽器地址欄輸入

http://localhost:3501/v1.0/invoke/frontend/method/dapr
http://localhost:3501/v1.0/invoke/frontend/method/dapr/get2
http://localhost:3501/v1.0/invoke/frontend/method/DaprDI

可以看到正常響應

 

 2.DaprCLI測試調用

打開cmd輸入

dapr invoke --app-id frontend --verb "GET" --method dapr

也可以看到調用成功

C:\Users\chesterychen>dapr invoke --app-id frontend --verb "GET" --method dapr
result is OK [{"date":"2021-09-24T14:20:51.2386681+08:00","temperatureC":47,"temperatureF":116,"summary":"Mild"},{"date":"2021-09-25T14:20:51.2386705+08:00","temperatureC":50,"temperatureF":121,"summary":"Mild"},{"date":"2021-09-26T14:20:51.2386707+08:00","temperatureC":34,"temperatureF":93,"summary":"Hot"},{"date":"2021-09-27T14:20:51.2386708+08:00","temperatureC":42,"temperatureF":107,"summary":"Bracing"},{"date":"2021-09-28T14:20:51.2386709+08:00","temperatureC":-19,"temperatureF":-2,"summary":"Warm"}]
App invoked successfully

 

PS:單機運行的情況下，每個服務的sidecar是一個進程，名爲daprd，下圖兩個分別是backend和frontend連個服務的

 鏈路追蹤

自承載的方式下，Dapr默認啓動了zipkin容器，可以通過以下鏈接查看

http://localhost:9411/zipkin/

 

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