Dapr-服務調用

前言

　上一篇對Dapr進行了了解，并搭建了Dapr環境。接下來就對Dapr的各個建構塊類型的了解、應用實際案例。

一、服務調用：

　在許多具有多個需要互相通信的服務的環境中，都會面臨着很多問題。如：

維護其他服務的位址。
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。
分布式應用程式調用鍊路追蹤。

　服務調用建構塊通過使用 Dapr 挎鬥作為服務的反向代理來解決這些難題。

　調用邏輯：

　服務調用就是應用程式可以使用 gRPC 或 HTTP 這樣的标準協定來發現并可靠地與其他應用程式通信。

　Dapr的服務調用如何工作的總覽圖，如下：

服務 A 對服務 B 發起HTTP/gRPC的調用。
Dapr使用在給定主機平台上運作的名稱解析元件發現服務B的位置。
Dapr 将消息轉發至服務B的Dapr Sidecar

注: Dapr Sidecar 之間的所有調用考慮到性能都優先使用 gRPC。僅服務與 Dapr Sidecar之間的調用可以是 HTTP 或 gRPC
服務 B的 Dapr Sidecar 将請求轉發至服務 B 上的特定端點 (或方法) 。服務 B 随後運作其業務邏輯代碼。
服務 B 發送響應給服務 A。響應将轉至服務 B 的Sidecar。
Dapr 将消息轉發至服務 A 的 Dapr Sidecar。
服務 A 接收響應。

　服務調用特性：

　　由于調用經過Sidecar，Dapr 可以注入一些有其他行為：

失敗時自動重試調用。
通過互相 (mTLS) 身份驗證（包括自動證書滾動更新），在服務之間進行調用。
使用通路控制政策控制用戶端可以執行的操作。
捕獲服務間所有調用的跟蹤和名額，以提供分布式調用鍊路追蹤與診斷。

二、調用示例：

　1、建立兩個項目：DaprFrontEnd（前端示例）、DaprBackEnd（後端示例）

　　DaprFrontEnd項目：Razor項目用于展示從後端示例中調用結果内容

　　DaprBackEnd項目：Api項目用于擷取資料

　2、DaprFrontEnd項目調整運作：

　　a) 修改綁定端口：

public static IHostBuilder CreateHostBuilder(string[] args) =>
    Host.CreateDefaultBuilder(args)
        .ConfigureWebHostDefaults(webBuilder =>
        {
            webBuilder.UseStartup<Startup>();
            webBuilder.UseUrls("http://0.0.0.0:8220");
        });

　　b)使用Dapr cli 指令啟動項目：

//dapr指令
dapr run --dapr-http-port 3511 --app-port 5000 --app-id backend dotnet  .\DaprBackEnd.dl

//輸出結果
Starting Dapr with id backend. HTTP Port: 3511. gRPC Port: 1030
time="2021-10-24T19:00:48.5801709+08:00" level=info msg="starting Dapr Runtime -- version 1.4.3 -- commit a8ee30180e1183e2a2e4d00c283448af6d73d0d0" app_id=backend instance=Coder scope=dapr.runtime type=log ver=1.4.3
time="2021-10-24T19:00:48.5831673+08:00" level=info msg="log level set to: info" app_id=backend instance=Coder scope=dapr.runtime type=log ver=1.4.3
time="2021-10-24T19:00:48.5890733+08:00" level=info msg="metrics server started on :1033/" app_id=backend instance=Coder scope=dapr.metrics type=log ver=1.4.3
time="2021-10-24T19:00:48.6178099+08:00" level=info msg="standalone mode configured" app_id=backend instance=Coder scope=dapr.runtime type=log ver=1.4.3
time="2021-10-24T19:00:48.6178272+08:00" level=info msg="app id: backend" app_id=backend instance=Coder scope=dapr.runtime type=log ver=1.4.3
time="2021-10-24T19:00:48.6205808+08:00" level=info msg="mTLS is disabled. Skipping certificate request and tls validation" app_id=backend instance=Coder scope=dapr.runtime type=log ver=1.4.3
time="2021-10-24T19:00:48.6835042+08:00" level=info msg="local service entry announced: backend -> 192.168.0.109:1038" app_id=backend instance=Coder scope=dapr.contrib type=log ver=1.4.3
time="2021-10-24T19:00:48.6835042+08:00" level=info msg="Initialized name resolution to mdns" app_id=backend instance=Coder scope=dapr.runtime type=log ver=1.4.3
time="2021-10-24T19:00:48.6855038+08:00" level=info msg="loading components" app_id=backend instance=Coder scope=dapr.runtime type=log ver=1.4.3
time="2021-10-24T19:00:48.7225025+08:00" level=info msg="component loaded. name: pubsub, type: pubsub.redis/v1" app_id=backend instance=Coder scope=dapr.runtime type=log ver=1.4.3
time="2021-10-24T19:00:48.7228271+08:00" level=info msg="waiting for all outstanding components to be processed" app_id=backend instance=Coder scope=dapr.runtime type=log ver=1.4.3
time="2021-10-24T19:00:48.7310234+08:00" level=info msg="component loaded. name: statestore, type: state.redis/v1" app_id=backend instance=Coder scope=dapr.runtime type=log ver=1.4.3
time="2021-10-24T19:00:48.732082+08:00" level=info msg="all outstanding components processed" app_id=backend instance=Coder scope=dapr.runtime type=log ver=1.4.3
time="2021-10-24T19:00:48.7374914+08:00" level=info msg="enabled gRPC tracing middleware" app_id=backend instance=Coder scope=dapr.runtime.grpc.api type=log ver=1.4.3
time="2021-10-24T19:00:48.7384898+08:00" level=info msg="enabled gRPC metrics middleware" app_id=backend instance=Coder scope=dapr.runtime.grpc.api type=log ver=1.4.3
time="2021-10-24T19:00:48.7434866+08:00" level=info msg="API gRPC server is running on port 1030" app_id=backend instance=Coder scope=dapr.runtime type=log ver=1.4.3
time="2021-10-24T19:00:48.7444869+08:00" level=info msg="enabled metrics http middleware" app_id=backend instance=Coder scope=dapr.runtime.http type=log ver=1.4.3
time="2021-10-24T19:00:48.7444869+08:00" level=info msg="enabled tracing http middleware" app_id=backend instance=Coder scope=dapr.runtime.http type=log ver=1.4.3
time="2021-10-24T19:00:48.7464879+08:00" level=info msg="http server is running on port 3511" app_id=backend instance=Coder scope=dapr.runtime type=log ver=1.4.3
time="2021-10-24T19:00:48.7464879+08:00" level=info msg="The request body size parameter is: 4" app_id=backend instance=Coder scope=dapr.runtime type=log ver=1.4.3
time="2021-10-24T19:00:48.7474861+08:00" level=info msg="enabled gRPC tracing middleware" app_id=backend instance=Coder scope=dapr.runtime.grpc.internal type=log ver=1.4.3
time="2021-10-24T19:00:48.7474861+08:00" level=info msg="enabled gRPC metrics middleware" app_id=backend instance=Coder scope=dapr.runtime.grpc.internal type=log ver=1.4.3
time="2021-10-24T19:00:48.7484875+08:00" level=info msg="internal gRPC server is running on port 1038" app_id=backend instance=Coder scope=dapr.runtime type=log ver=1.4.3
time="2021-10-24T19:00:48.7494884+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=Coder scope=dapr.runtime type=log ver=1.4.3
Updating metadata for app command: dotnet .\DaprBackEnd.dll
You're up and running! Both Dapr and your app logs will appear here.

== APP == info: Microsoft.Hosting.Lifetime[0]
== APP ==       Now listening on: http://0.0.0.0:8220
== 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: F:\coding\DaprMultiContainer\DaprBackEnd\bin\Debug\netcoreapp3.1

　3、DaprBackEnd項目調整：

　　a) 修改端口

public static IHostBuilder CreateHostBuilder(string[] args) =>
    Host.CreateDefaultBuilder(args)
        .ConfigureWebHostDefaults(webBuilder =>
        {
            webBuilder.UseStartup<Startup>();
            webBuilder.UseUrls("http://0.0.0.0:8230");
        });

　　b) 添加Dapr.AspNetCore包

Install-Package Dapr.AspNetCore

　　c) 注入Dapr

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

　　d) 調用DaprBackEnd 服務接口：

public class IndexModel : PageModel
{
    private readonly DaprClient _daprClient;

    public IndexModel(DaprClient daprClient)
    {
        _daprClient = daprClient ?? throw new ArgumentNullException(nameof(daprClient));
    }

    public async Task OnGet()
    {
        //方式一：使用HttpClient
        //using var httpClient = DaprClient.CreateInvokeHttpClient();
        //var result = await httpClient.GetAsync("http://backend/WeatherForecast");
        //var resultContent = await result.Content.ReadAsStringAsync();

        //方式二：使用DaprClient
        var forecasts = await _daprClient.InvokeMethodAsync<IEnumerable<WeatherForecast>>(HttpMethod.Get, "backend", "weatherforecast");
        ViewData["WeatherForecastData"] = forecasts;

        //方式三：Grpc方式調用
        //var forecastsGrpc = await _daprClient.InvokeMethodGrpcAsync<IEnumerable<WeatherForecast>>("backend", "weatherforecast");
        //ViewData["WeatherForecastData"] = forecasts;
    }
}

　　e) 通過Dapr CLI啟動DaprFrontEnd，指定sidecar端口為3501，預設為3500，指定app-port是8230，與DaprFrontEnd預設端口保持一緻

//指令
dapr run --dapr-http-port 3501 --app-port 8230  --app-id frontend dotnet  .\DaprFrontEnd.dll

//輸出：
Starting Dapr with id frontend. HTTP Port: 3501. gRPC Port: 29840
time="2021-10-24T19:31:25.1254888+08:00" level=info msg="starting Dapr Runtime -- version 1.4.3 -- commit a8ee30180e1183e2a2e4d00c283448af6d73d0d0" app_id=frontend instance=Coder scope=dapr.runtime type=log ver=1.4.3
time="2021-10-24T19:31:25.1284879+08:00" level=info msg="log level set to: info" app_id=frontend instance=Coder scope=dapr.runtime type=log ver=1.4.3
time="2021-10-24T19:31:25.1294861+08:00" level=info msg="metrics server started on :29841/" app_id=frontend instance=Coder scope=dapr.metrics type=log ver=1.4.3
time="2021-10-24T19:31:25.1458074+08:00" level=info msg="standalone mode configured" app_id=frontend instance=Coder scope=dapr.runtime type=log ver=1.4.3
time="2021-10-24T19:31:25.1458074+08:00" level=info msg="app id: frontend" app_id=frontend instance=Coder scope=dapr.runtime type=log ver=1.4.3
time="2021-10-24T19:31:25.1463505+08:00" level=info msg="mTLS is disabled. Skipping certificate request and tls validation" app_id=frontend instance=Coder scope=dapr.runtime type=log ver=1.4.3
time="2021-10-24T19:31:25.1837081+08:00" level=info msg="local service entry announced: frontend -> 192.168.0.109:29845" app_id=frontend instance=Coder scope=dapr.contrib type=log ver=1.4.3
time="2021-10-24T19:31:25.1837081+08:00" level=info msg="Initialized name resolution to mdns" app_id=frontend instance=Coder scope=dapr.runtime type=log ver=1.4.3
time="2021-10-24T19:31:25.184711+08:00" level=info msg="loading components" app_id=frontend instance=Coder scope=dapr.runtime type=log ver=1.4.3
time="2021-10-24T19:31:25.2316059+08:00" level=info msg="component loaded. name: pubsub, type: pubsub.redis/v1" app_id=frontend instance=Coder scope=dapr.runtime type=log ver=1.4.3
time="2021-10-24T19:31:25.2316059+08:00" level=info msg="waiting for all outstanding components to be processed" app_id=frontend instance=Coder scope=dapr.runtime type=log ver=1.4.3
time="2021-10-24T19:31:25.2419333+08:00" level=info msg="component loaded. name: statestore, type: state.redis/v1" app_id=frontend instance=Coder scope=dapr.runtime type=log ver=1.4.3
time="2021-10-24T19:31:25.2423401+08:00" level=info msg="all outstanding components processed" app_id=frontend instance=Coder scope=dapr.runtime type=log ver=1.4.3
time="2021-10-24T19:31:25.2434172+08:00" level=info msg="enabled gRPC tracing middleware" app_id=frontend instance=Coder scope=dapr.runtime.grpc.api type=log ver=1.4.3
time="2021-10-24T19:31:25.2434172+08:00" level=info msg="enabled gRPC metrics middleware" app_id=frontend instance=Coder scope=dapr.runtime.grpc.api type=log ver=1.4.3
time="2021-10-24T19:31:25.2439954+08:00" level=info msg="API gRPC server is running on port 29840" app_id=frontend instance=Coder scope=dapr.runtime type=log ver=1.4.3
time="2021-10-24T19:31:25.2439954+08:00" level=info msg="enabled metrics http middleware" app_id=frontend instance=Coder scope=dapr.runtime.http type=log ver=1.4.3
time="2021-10-24T19:31:25.2445399+08:00" level=info msg="enabled tracing http middleware" app_id=frontend instance=Coder scope=dapr.runtime.http type=log ver=1.4.3
time="2021-10-24T19:31:25.2450858+08:00" level=info msg="http server is running on port 3501" app_id=frontend instance=Coder scope=dapr.runtime type=log ver=1.4.3
time="2021-10-24T19:31:25.2450858+08:00" level=info msg="The request body size parameter is: 4" app_id=frontend instance=Coder scope=dapr.runtime type=log ver=1.4.3
time="2021-10-24T19:31:25.2456242+08:00" level=info msg="enabled gRPC tracing middleware" app_id=frontend instance=Coder scope=dapr.runtime.grpc.internal type=log ver=1.4.3
time="2021-10-24T19:31:25.2461714+08:00" level=info msg="enabled gRPC metrics middleware" app_id=frontend instance=Coder scope=dapr.runtime.grpc.internal type=log ver=1.4.3
time="2021-10-24T19:31:25.2467123+08:00" level=info msg="internal gRPC server is running on port 29845" app_id=frontend instance=Coder scope=dapr.runtime type=log ver=1.4.3
time="2021-10-24T19:31:25.2478066+08:00" level=info msg="application protocol: http. waiting on port 8230.  This will block until the app is listening on that port." app_id=frontend instance=Coder scope=dapr.runtime type=log ver=1.4.3
Updating metadata for app command: dotnet .\DaprFrontEnd.dll
You're up and running! Both Dapr and your app logs will appear here.

== APP == info: Microsoft.Hosting.Lifetime[0]
== APP ==       Now listening on: http://0.0.0.0:8230
== 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: F:\coding\DaprMultiContainer\DaprFrontEnd\bin\Debug\netcoreapp3.1
time="2021-10-24T19:31:26.10297+08:00" level=info msg="application discovered on port 8230" app_id=frontend instance=Coder scope=dapr.runtime type=log ver=1.4.3
time="2021-10-24T19:31:26.2373056+08:00" level=info msg="application configuration loaded" app_id=frontend instance=Coder scope=dapr.runtime type=log ver=1.4.3
time="2021-10-24T19:31:26.2422307+08:00" level=info msg="actor runtime started. actor idle timeout: 1h0m0s. actor scan interval: 30s" app_id=frontend instance=Coder scope=dapr.runtime.actor type=log ver=1.4.3
time="2021-10-24T19:31:26.2677804+08:00" level=info msg="dapr initialized. Status: Running. Init Elapsed 1121.4194ms" app_id=frontend instance=Coder scope=dapr.runtime type=log ver=1.4.3
time="2021-10-24T19:31:26.5035983+08:00" level=info msg="placement tables updated, version: 0" app_id=frontend instance=Coder scope=dapr.runtime.actor.internal.placement type=log ver=1.4.3

　　檢視dapr運作應用情況：

dapr list
  APP ID    HTTP PORT  GRPC PORT  APP PORT  COMMAND               AGE  CREATED              PID
  backend   3511       1030       5000      dotnet .\DaprBack...  32m  2021-10-24 19:00.47  4900
  frontend  3501       29840      8230      dotnet .\DaprFron...  1m   2021-10-24 19:31.24  20856

　4、dapr cli 調用方式：

dapr invoke --app-id backend --verb "GET" --method weatherforecast

三、Dapr擴充功能：

　1、鍊路跟蹤檢視：自承載的方式下，Dapr預設啟動了zipkin容器，可以通過以下連結檢視： http://localhost:9411/zipkin/

　2、Dapr Dashboard：

　　a) 啟動 Dapr Dashboard：

dapr dashboard

　　b) 檢視頁面：http://localhost:8080/

總結：

　本篇對建構塊中服務調用進行了解，并在.NET Core 程式中進行了驗證。　　　

Dapr-服務調用

前言

一、服務調用：

調用邏輯：

服務調用特性：

二、調用示例：

三、Dapr擴充功能：

總結：

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