我们是怎么实现Grpc CodeFirst

我们是怎么实现Grpc CodeFirst
前言:

Grpc默认是ProtoFirst的，即先写 proto文件，再生成代码，需要人工维护proto，生成的代码也不友好，所以出现了Grpc CodeFirst，下面来说说我们是怎么实现Grpc CodeFirst

目录：

实现和WCF一样的CodeFirst

(1). 实现Grpc CodeFirst,  简化WCF一定要抽取接口的问题

(2). 通过代码生成proto和注释，给第三方语言使用

(3). 实现Grpc DashBoard，用于Http远程调用和管理

(4). 实现服务注册与发现

(5). 实现分布式日志跟踪

(6). 日志监控等等

我们是怎么实现Grpc CodeFirst

1.要实现CodeFirst先要了解ProtoFirst生成的代码，下面我截了部分生成代码

(1).关键是这个BindService，用于把实现的Grpc方法绑定到GrpcServiceDefinition

public static partial class Greeter
{

static readonly string __ServiceName = "helloworld.Greeter";

static readonly grpc::Marshaller<global::Helloworld.HelloRequest> __Marshaller_helloworld_HelloRequest = grpc::Marshallers.Create((arg) => global::Google.Protobuf.MessageExtensions.ToByteArray(arg), global::Helloworld.HelloRequest.Parser.ParseFrom);
static readonly grpc::Marshaller<global::Helloworld.HelloReply> __Marshaller_helloworld_HelloReply = grpc::Marshallers.Create((arg) => global::Google.Protobuf.MessageExtensions.ToByteArray(arg), global::Helloworld.HelloReply.Parser.ParseFrom);

static readonly grpc::Method<global::Helloworld.HelloRequest, global::Helloworld.HelloReply> __Method_SayHello = new grpc::Method<global::Helloworld.HelloRequest, global::Helloworld.HelloReply>(
    grpc::MethodType.Unary,
    __ServiceName,
    "SayHello",
    __Marshaller_helloworld_HelloRequest,
    __Marshaller_helloworld_HelloReply);

static readonly grpc::Method<global::Helloworld.HelloRequest, global::Helloworld.HelloReply> __Method_SayHelloStream = new grpc::Method<global::Helloworld.HelloRequest, global::Helloworld.HelloReply>(
    grpc::MethodType.ClientStreaming,
    __ServiceName,
    "SayHelloStream",
    __Marshaller_helloworld_HelloRequest,
    __Marshaller_helloworld_HelloReply);

/// <summary>Creates service definition that can be registered with a server</summary>
/// <param name="serviceImpl">An object implementing the server-side handling logic.</param>
public static grpc::ServerServiceDefinition BindService(GreeterBase serviceImpl)
{
  return grpc::ServerServiceDefinition.CreateBuilder()
      .AddMethod(__Method_SayHello, serviceImpl.SayHello)
      .AddMethod(__Method_SayHelloStream, serviceImpl.SayHelloStream).Build();
}

/// <summary>Register service method with a service binder with or without implementation. Useful when customizing the  service binding logic.
/// Note: this method is part of an experimental API that can change or be removed without any prior notice.</summary>
/// <param name="serviceBinder">Service methods will be bound by calling <c>AddMethod</c> on this object.</param>
/// <param name="serviceImpl">An object implementing the server-side handling logic.</param>
public static void BindService(grpc::ServiceBinderBase serviceBinder, GreeterBase serviceImpl)
{
  serviceBinder.AddMethod(__Method_SayHello, serviceImpl == null ? null : new grpc::UnaryServerMethod<global::Helloworld.HelloRequest, global::Helloworld.HelloReply>(serviceImpl.SayHello));
  serviceBinder.AddMethod(__Method_SayHelloStream, serviceImpl == null ? null : new grpc::ClientStreamingServerMethod<global::Helloworld.HelloRequest, global::Helloworld.HelloReply>(serviceImpl.SayHelloStream));
}

}

(2).__Marshaller_helloworld_HelloRequest这个是实现protobuffer的序列化和反序列化的一个委托

服务的请求参数和返回参数，我们使用Protobuf-net来实现序列化和反序列化，和 WCF一样需要给类打上标签

/// <summary>
/// 加法请求参数
/// </summary>
[ProtoContract]
public class AddRequest
{
    /// <summary>
    /// 第一个数字
    /// </summary>
    [ProtoMember(1)]
    public int Num1 { get; set; }

    /// <summary>
    /// 第二个数字
    /// </summary>
    [ProtoMember(2)]
    public int Num2 { get; set; }
}

2.要实现CodeFirst需要实现这个BindService，把我们的Grpc方法添加到ServerServiceDefinition

(1).我们让Grpc服务实现IGrpcService空接口，用于标识是GrpcService

/// <summary>
/// MathGrpc
/// </summary>
public class MathGrpc : IGrpcService
{
    /// <summary>
    /// 加法
    /// </summary>
    /// <param name="request"></param>
    /// <param name="context"></param>
    /// <returns></returns>
    public Task<IntMessage> Add(AddRequest request, ServerCallContext context)
    {
        var result = new IntMessage();
        result.Value = request.Num1 + request.Num2;
        return Task.FromResult(result);
    }

}

(2).获取实现了IGrpcService接口的类，然后反射获取方法，再添加到ServerServiceDefinition即可

    /// <summary>
/// 注入IGrpcService
/// </summary>
/// <param name="grpcServices"></param>
/// <returns></returns>
private ServerBuilder UseGrpcService(IEnumerable<IGrpcService> grpcServices)
{
    var builder = ServerServiceDefinition.CreateBuilder();
    grpcServices.ToList().ForEach(grpc => GrpcMethodHelper.AutoRegisterMethod(grpc, builder));
    _serviceDefinitions.Add(builder.Build());
    return this;
}

未完，待续，欢迎评论拍砖

这些功能早在2018年就已经实现并运行在生产，感兴趣的同学可以去 github上查看，你要的都有，欢迎提issue

作　　者： 易   磊(Rabbit_Yi)
出　　处： http://www.cnblogs.com/rabbityi/