Dapr 运用

Dapr 运用

• 前置条件
  • Docker
  • Win10

Dapr 部署

本文将采用本地部署的方式。

安装 Dapr CLI

打开 Windows PowerShell 或 cmd ，运行以下命令以安装 Dapr CLI，并添加安装路径到系统环境变量中。

powershell -Command "iwr -useb https://raw.githubusercontent.com/dapr/cli/master/install/install.ps1 | iex"

这里安装可能会失败。如果失败可以手动安装。

• 打开 Dapr 发布页面下载 dapr_windows_amd64.zip
• 解压文件 zip 文件
• 把解压后的文件拷贝到 C:\dapr 中

安装 MySql

Docker 启动 Mysql

docker run --name mysqltest -e MYSQL_ROOT_PASSWORD=123456 -d mysql

使用 Dapr CLI 安装 Darp runtime

在 Windows PowerShell 或 cmd 中使用命令 dapr init 以安装 Dapr。

同时可以在 Docker 中查看 Dapr 容器。

至此，一个本地 Dapr 服务搭建完成。

使用 Asp.Net Core 搭建 ProductService 服务

ProductService 提供两个服务

• 获取所有产品集合
• 添加产品

1. 使用 ASP.Net Core 创建 ProductService ，具体参考源码

2. Dapr 启动 ProductService

   dapr run --app-id productService --app-port 5000 dotnet run
   

3. 获取所有产品集合，使用 curl 命令

   curl -X GET http://localhost:5000/getlist
   

   或者

   curl -X GET http://localhost:54680/v1.0/invoke/productService/method/getlist
   

4. 添加一个产品

   curl -X POST https://localhost:5001/product -H "Content-Type: application/json" -d "{ \"id\": \"14a3611d-1561-455f-9c72-381eed2f6ee3\" }"
   

5. 重点，通过 Dapr 添加一个产品，先看添加产品的代码

    /// <summary>
    /// 创建产品
    /// </summary>
    /// <param name="productCreate">产品创建模型</param>
    /// <returns></returns>
    [Topic("product")]
    [HttpPost("product")]
    public async Task<bool> CreateProduct(ProductCreate productCreate)
    {
        _productContext.Products.Add(new Product
        {
            ProductID = productCreate.ID
        });
        return await _productContext.SaveChangesAsync() == 1;
    }
   

   • 使用 Dapr cli 发布事件

      dapr invoke -a productService -m product -p "{\"id\":\"b1ccf14a-408a-428e-b0f0-06b97cbe4135\"}"
     

     输出为：

     true
     App invoked successfully
     

   • 使用 curl 命令直接请求 ProductService 地址

     curl -X POST http://localhost:5000/product -H "Content-Type: application/json" -d "{ \"id\": \"14a3611d-1561-455f-9c72-381eed2f64e3\" }"
     

     输出为：

     true
     

   • 使用 curl 命令通过 Dapr runtime

     curl -X POST http://localhost:54680/v1.0/invoke/productService/method/product -H "Content-Type: application/json" -d "{ \"id\": \"14a3611d-1561-455f-9c72-381eed2f54e3\" }"
     

     输出为：

     true
     

注意：

• Dapr 使用 App 端口号应与服务端口号相同，例如：ASP.Net Core 服务端口号为5000，则在使用 Dapr 托管应用程序时的端口号也应使用 5000

至此， ProductService 创建完成。

使用 Golang 创建 gRPC Server

1. 创建 Server

   package main
   
   import (
       "context"
       "fmt"
       "log"
       "net"
   
       "github.com/golang/protobuf/ptypes/any"
       "github.com/golang/protobuf/ptypes/empty"
   
       pb "github.com/dapr/go-sdk/daprclient"
       "google.golang.org/grpc"
   )
   
   // server is our user app
   type server struct {
   }
   
   func main() {
       // create listiner
       lis, err := net.Listen("tcp", ":4000")
       if err != nil {
           log.Fatalf("failed to listen: %v", err)
       }
   
       // create grpc server
       s := grpc.NewServer()
       pb.RegisterDaprClientServer(s, &server{})
   
       fmt.Println("Client starting...")
   
       // and start...
       if err := s.Serve(lis); err != nil {
           log.Fatalf("failed to serve: %v", err)
       }
   }
   
   // Sample method to invoke
   func (s *server) MyMethod() string {
       return "Hi there!"
   }
   
   // This method gets invoked when a remote service has called the app through Dapr
   // The payload carries a Method to identify the method, a set of metadata properties and an optional payload
   func (s *server) OnInvoke(ctx context.Context, in *pb.InvokeEnvelope) (*any.Any, error) {
       var response string
   
       fmt.Println(fmt.Sprintf("Got invoked with: %s", string(in.Data.Value)))
   
       switch in.Method {
       case "MyMethod":
           response = s.MyMethod()
       }
       return &any.Any{
           Value: []byte(response),
       }, nil
   }
   
   // Dapr will call this method to get the list of topics the app wants to subscribe to. In this example, we are telling Dapr
   // To subscribe to a topic named TopicA
   func (s *server) GetTopicSubscriptions(ctx context.Context, in *empty.Empty) (*pb.GetTopicSubscriptionsEnvelope, error) {
       return &pb.GetTopicSubscriptionsEnvelope{
           Topics: []string{"TopicA"},
       }, nil
   }
   
   // Dapper will call this method to get the list of bindings the app will get invoked by. In this example, we are telling Dapr
   // To invoke our app with a binding named storage
   func (s *server) GetBindingsSubscriptions(ctx context.Context, in *empty.Empty) (*pb.GetBindingsSubscriptionsEnvelope, error) {
       return &pb.GetBindingsSubscriptionsEnvelope{
           Bindings: []string{"storage"},
       }, nil
   }
   
   // This method gets invoked every time a new event is fired from a registerd binding. The message carries the binding name, a payload and optional metadata
   func (s *server) OnBindingEvent(ctx context.Context, in *pb.BindingEventEnvelope) (*pb.BindingResponseEnvelope, error) {
       fmt.Println("Invoked from binding")
       return &pb.BindingResponseEnvelope{}, nil
   }
   
   // This method is fired whenever a message has been published to a topic that has been subscribed. Dapr sends published messages in a CloudEvents 0.3 envelope.
   func (s *server) OnTopicEvent(ctx context.Context, in *pb.CloudEventEnvelope) (*empty.Empty, error) {
       fmt.Println("Topic message arrived")
       return &empty.Empty{}, nil
   }
   
   

2. 使用 Dapr 命令启动 StorageService

    dapr run --app-id client --protocol grpc --app-port 4000 go run main.go
   

注意：

• Dapr 使用 App 端口号应与服务端口号相同，使用 --protocal grpc 指定通讯协议为 grpc 。此外，OnInvoke 中的 switch 方法用于调用者路由。

使用 ASP.NET Core 创建 StorageService

1. 使用 NuGet 获取程序管理包控制台安装以下包

   • Dapr.AspNetCore
   • Dapr.Client.Grpc
   • Grpc.AspNetCore
   • Grpc.Net.Client
   • Grpc.Tools

2. Startup.cs 文件中修改代码如下：

   /// <summary>
   /// This method gets called by the runtime. Use this method to add services to the container.
   /// </summary>
   /// <param name="services">Services.</param>
   public void ConfigureServices(IServiceCollection services)
   {
       services.AddControllers().AddDapr();
       services.AddDbContextPool<StorageContext>(options => { options.UseMySql(Configuration.GetConnectionString("MysqlConnection")); });
   }
   

    /// <summary>
   /// This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
   /// </summary>
   /// <param name="app">app.</param>
   /// <param name="env">env.</param>
   public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
   {
       if (env.IsDevelopment())
       {
           app.UseDeveloperExceptionPage();
       }
   
       app.UseRouting();
       app.UseCloudEvents();
   
       app.UseAuthorization();
   
       app.UseEndpoints(endpoints =>
       {
           endpoints.MapSubscribeHandler();
           endpoints.MapControllers();
       });
   }
   

3. 添加 StorageController.cs 文件，内容如下

   using System;
   using System.Linq;
   using System.Threading.Tasks;
   using Dapr.Client.Grpc;
   using Google.Protobuf;
   using Grpc.Net.Client;
   using Microsoft.AspNetCore.Mvc;
   using StorageService.Api.Entities;
   
   namespace StorageService.Api.Controllers
   {
       [ApiController]
       public class StorageController : ControllerBase
       {
           private readonly StorageContext _storageContext;
   
           public StorageController(StorageContext storageContext)
           {
               _storageContext = storageContext;
           }
   
           /// <summary>
           /// 初始化仓库.
           /// </summary>
           /// <returns>是否成功.</returns>
           [HttpGet("InitialStorage")]
           public async Task<bool> InitialStorage()
           {
               string defaultPort = Environment.GetEnvironmentVariable("DAPR_GRPC_PORT") ?? "54681";
   
               // Set correct switch to make insecure gRPC service calls. This switch must be set before creating the GrpcChannel.
               AppContext.SetSwitch("System.Net.Http.SocketsHttpHandler.Http2UnencryptedSupport", true);
   
               // Create Client
               string daprUri = $"http://127.0.0.1:{defaultPort}";
               GrpcChannel channel = GrpcChannel.ForAddress(daprUri);
               var client = new Dapr.Client.Grpc.Dapr.DaprClient(channel);
               Console.WriteLine(daprUri);
   
               InvokeServiceResponseEnvelope result = await client.InvokeServiceAsync(new InvokeServiceEnvelope
               {
                   Method = "MyMethod",
                   Id = "client",
                   Data = new Google.Protobuf.WellKnownTypes.Any
                   {
                       Value = ByteString.CopyFromUtf8("Hello ProductService")
                   }
               });
               Console.WriteLine("this is call result:" + result.Data.Value.ToStringUtf8());
               //var productResult = result.Data.Unpack<ProductList.V1.ProductList>();
               //Console.WriteLine("this is call result:" + productResult.Results.FirstOrDefault());
               return true;
           }
   
           /// <summary>
           /// 修改库存
           /// </summary>
           /// <param name="storage"></param>
           /// <returns></returns>
           [HttpPut("Reduce")]
           public bool Reduce(Storage storage)
           {
               Storage storageFromDb = _storageContext.Storage.FirstOrDefault(q => q.ProductID.Equals(storage.ProductID));
               if (storageFromDb == null)
               {
                   return false;
               }
   
               if (storageFromDb.Amount <= storage.Amount)
               {
                   return false;
               }
   
               storageFromDb.Amount -= storage.Amount;
               return true;
           }
       }
   }
   

4. 使用 Dapr cli 启用 StorageService 服务

   dapr run --app-id storageService --app-port 5003 dotnet run
   

5. 使用 curl 命令访问 StorageService InitialStorage 方法

   curl -X GET http://localhost:56349/v1.0/invoke/storageService/method/InitialStorage
   

   输入

   true
   

   其中打印信息为：

   this is call result:Hi there!
   

注意：

• Dapr 使用 App 端口号应与服务端口号相同，例如：ASP.Net Core 服务端口号为5003，则在使用 Dapr 托管应用程序时的端口号也应使用 5003，在 Client.InvokeServiceAsync 中的 Id 指被调用方的 App-Id ,Method 指被调用方方法名称。参考 Go Server 中 OnInvoke 方法的 Switch 。

源码地址