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

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

Dapr 启动 ProductService

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

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

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\" }"

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

创建 Server

package mainimport ("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 listinerlis, err := net.Listen("tcp", ":4000")if err != nil {log.Fatalf("failed to listen: %v", err)}// create grpc servers := 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 stringfmt.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
}

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

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

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();});
}

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 Clientstring 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;}}
}

使用 Dapr cli 启用 StorageService 服务

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

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：https://github.com/SoMeDay-Zhang/DaprDemos