V2_12_C#_gRPC微服务通信实战

C# gRPC 微服务通信实战：比 REST 快 5 倍的高性能方案

系列导航

本文是 《.NET 微服务架构实战系列》 第十二篇

• 第一篇：微服务架构概述与 .NET 技术栈选型
• 第二篇：Docker 容器化基础
• 第三篇：Docker Compose 多容器编排
• 第四篇：微服务项目结构设计
• 第五篇：服务发现与注册（Consul）
• 第六篇：API 网关实战（Ocelot/YARP）
• 第七篇：分布式配置中心
• 第八篇：数据库 per 服务模式
• 第九篇：CQRS 模式实战
• 第十篇：事件驱动架构
• 第十一篇：分布式事务与 Saga 模式
• 第十二篇：gRPC 微服务通信实战（本文）
• 第十三篇：日志与监控实战
• 第十四篇：分布式链路追踪

前言：gRPC vs REST 对比

在微服务架构中，服务间通信是核心问题之一。传统的 REST API 虽然简单易用，但在高性能场景下存在瓶颈。gRPC 作为 Google 开源的高性能 RPC 框架，正在成为微服务通信的首选方案。

gRPC 与 REST 核心对比

性能对比实测

测试场景：10000 次调用，传输 1KB 数据

REST (JSON + HTTP/1.1):
– 总耗时: 2.8 秒
– 吞吐量: 3571 req/s
– 平均延迟: 0.28 ms

gRPC (Protobuf + HTTP/2):
– 总耗时: 0.6 秒
– 吞吐量: 16666 req/s
– 平均延迟: 0.06 ms

性能提升: 约 4.7 倍

第一部分：gRPC 基础

1.1 Protocol Buffers 简介

Protocol Buffers（简称 Protobuf）是 Google 开发的一种轻量、高效的结构化数据序列化机制。

核心优势：

• 二进制格式，体积比 JSON 小 3-10 倍
• 序列化/反序列化速度快 3-5 倍
• 强类型定义，编译时类型检查
• 向后兼容，支持字段演进

1.2 Proto 文件定义

创建 protos/user.proto 文件：

syntax = "proto3";

option csharp_namespace = "UserService.Protos";

package user;

// 用户服务定义
service UserService {
// 一元 RPC：获取单个用户
rpc GetUser (GetUserRequest) returns (UserResponse);

// 一元 RPC：创建用户
rpc CreateUser (CreateUserRequest) returns (UserResponse);

// 服务端流：获取用户列表
rpc ListUsers (ListUsersRequest) returns (stream UserResponse);

// 客户端流：批量创建用户
rpc BatchCreateUsers (stream CreateUserRequest) returns (BatchCreateResponse);

// 双向流：实时用户状态更新
rpc StreamUserStatus (stream UserStatusRequest) returns (stream UserStatusResponse);
}

// 消息定义
message GetUserRequest {
int32 user_id = 1;
}

message CreateUserRequest {
string username = 1;
string email = 2;
string phone = 3;
int32 age = 4;
}

message ListUsersRequest {
int32 page = 1;
int32 page_size = 2;
string keyword = 3;
}

message UserResponse {
int32 id = 1;
string username = 2;
string email = 3;
string phone = 4;
int32 age = 5;
string created_at = 6;
UserStatus status = 7;
}

message BatchCreateResponse {
int32 success_count = 1;
int32 fail_count = 2;
repeated UserResponse users = 3;
}

message UserStatusRequest {
int32 user_id = 1;
string action = 2; // "online", "offline", "busy"
}

message UserStatusResponse {
int32 user_id = 1;
UserStatus status = 2;
string updated_at = 3;
}

enum UserStatus {
UNKNOWN = 0;
ONLINE = 1;
OFFLINE = 2;
BUSY = 3;
}

1.3 Proto 文件规范说明

// syntax 指定 proto 版本，推荐使用 proto3
syntax = "proto3";

// C# 命名空间
option csharp_namespace = "MyService.Protos";

// 包名，防止消息类型冲突
package myservice;

// 字段编号规则：
// 1-15: 单字节编码，用于高频字段
// 16-2047: 双字节编码，用于低频字段
// 19000-19999: 保留，不可使用

message Example {
int32 id = 1; // 高频字段，使用小编号
string name = 2; // 高频字段
string description = 16; // 低频字段，使用大编号

// 保留字段（已删除但需保留编号）
reserved 3, 4, 5;
reserved "old_field", "deprecated_field";
}

第二部分：创建 gRPC 服务端

2.1 项目创建与配置

# 创建 gRPC 服务项目
dotnet new grpc -n UserGrpcService

# 进入项目目录
cd UserGrpcService

# 添加必要包
dotnet add package Grpc.AspNetCore
dotnet add package Microsoft.EntityFrameworkCore.SqlServer
dotnet add package AutoMapper.Extensions.Microsoft.DependencyInjection

2.2 项目结构

UserGrpcService/
├── Protos/
│ └── user.proto
├── Services/
│ └── UserGrpcService.cs
├── Repositories/
│ ├── IUserRepository.cs
│ └── UserRepository.cs
├── Models/
│ └── User.cs
├── Data/
│ └── UserDbContext.cs
├── Mappings/
│ └── MappingProfile.cs
├── appsettings.json
└── Program.cs

2.3 配置文件 appsettings.json

{
"Kestrel": {
"Endpoints": {
"Grpc": {
"Url": "https://localhost:5001",
"Protocols": "Http2"
},
"Http": {
"Url": "http://localhost:5000",
"Protocols": "Http1"
}
}
},
"ConnectionStrings": {
"DefaultConnection": "Server=localhost;Database=UserDb;Trusted_Connection=True;"
},
"Grpc": {
"EnableReflection": true,
"MaxReceiveMessageSize": 10485760,
"MaxSendMessageSize": 10485760
},
"Logging": {
"LogLevel": {
"Default": "Information",
"Microsoft": "Warning",
"Grpc": "Information"
}
}
}

2.4 实体模型 Models/User.cs

namespace UserGrpcService.Models;

public class User
{
public int Id { get; set; }
public string Username { get; set; } = string.Empty;
public string Email { get; set; } = string.Empty;
public string Phone { get; set; } = string.Empty;
public int Age { get; set; }
public DateTime CreatedAt { get; set; }
public UserStatus Status { get; set; }
}

public enum UserStatus
{
Unknown = 0,
Online = 1,
Offline = 2,
Busy = 3
}

2.5 数据库上下文 Data/UserDbContext.cs

using Microsoft.EntityFrameworkCore;
using UserGrpcService.Models;

namespace UserGrpcService.Data;

public class UserDbContext : DbContext
{
public UserDbContext(DbContextOptions<UserDbContext> options)
: base(options) { }

public DbSet<User> Users { get; set; }

protected override void OnModelCreating(ModelBuilder modelBuilder)
{
modelBuilder.Entity<User>(entity =>
{
entity.HasKey(e => e.Id);
entity.HasIndex(e => e.Email).IsUnique();
entity.HasIndex(e => e.Username).IsUnique();
entity.Property(e => e.Username).HasMaxLength(50).IsRequired();
entity.Property(e => e.Email).HasMaxLength(100).IsRequired();
});

// 种子数据
modelBuilder.Entity<User>().HasData(
new User { Id = 1, Username = "admin", Email = "admin@example.com",
Phone = "13800138000", Age = 30, CreatedAt = DateTime.UtcNow,
Status = UserStatus.Online },
new User { Id = 2, Username = "test", Email = "test@example.com",
Phone = "13900139000", Age = 25, CreatedAt = DateTime.UtcNow,
Status = UserStatus.Offline }
);
}
}

2.6 仓储接口与实现

接口 Repositories/IUserRepository.cs：

using UserGrpcService.Models;

namespace UserGrpcService.Repositories;

public interface IUserRepository
{
Task<User?> GetByIdAsync(int id);
Task<IEnumerable<User>> GetListAsync(int page, int pageSize, string? keyword);
Task<User> CreateAsync(User user);
Task<IEnumerable<User>> BatchCreateAsync(IEnumerable<User> users);
Task<User> UpdateStatusAsync(int userId, UserStatus status);
Task<int> GetTotalCountAsync(string? keyword);
}

实现 Repositories/UserRepository.cs：

using Microsoft.EntityFrameworkCore;
using UserGrpcService.Data;
using UserGrpcService.Models;

namespace UserGrpcService.Repositories;

public class UserRepository : IUserRepository
{
private readonly UserDbContext _context;
private readonly ILogger<UserRepository> _logger;

public UserRepository(UserDbContext context, ILogger<UserRepository> logger)
{
_context = context;
_logger = logger;
}

public async Task<User?> GetByIdAsync(int id)
{
return await _context.Users.FindAsync(id);
}

public async Task<IEnumerable<User>> GetListAsync(int page, int pageSize, string? keyword)
{
var query = _context.Users.AsQueryable();

if (!string.IsNullOrWhiteSpace(keyword))
{
query = query.Where(u =>
u.Username.Contains(keyword) ||
u.Email.Contains(keyword));
}

return await query
.OrderByDescending(u => u.CreatedAt)
.Skip((page – 1) * pageSize)
.Take(pageSize)
.ToListAsync();
}

public async Task<User> CreateAsync(User user)
{
user.CreatedAt = DateTime.UtcNow;
_context.Users.Add(user);
await _context.SaveChangesAsync();
_logger.LogInformation("User created: {UserId}", user.Id);
return user;
}

public async Task<IEnumerable<User>> BatchCreateAsync(IEnumerable<User> users)
{
foreach (var user in users)
{
user.CreatedAt = DateTime.UtcNow;
_context.Users.Add(user);
}
await _context.SaveChangesAsync();
_logger.LogInformation("Batch created {Count} users", users.Count());
return users;
}

public async Task<User> UpdateStatusAsync(int userId, UserStatus status)
{
var user = await _context.Users.FindAsync(userId);
if (user == null)
throw new InvalidOperationException($"User {userId} not found");

user.Status = status;
await _context.SaveChangesAsync();
_logger.LogInformation("User {UserId} status updated to {Status}", userId, status);
return user;
}

public async Task<int> GetTotalCountAsync(string? keyword)
{
var query = _context.Users.AsQueryable();

if (!string.IsNullOrWhiteSpace(keyword))
{
query = query.Where(u =>
u.Username.Contains(keyword) ||
u.Email.Contains(keyword));
}

return await query.CountAsync();
}
}

2.7 gRPC 服务实现 Services/UserGrpcService.cs

using Grpc.Core;
using UserGrpcService.Protos;
using UserGrpcService.Repositories;
using UserGrpcService.Models;
using AutoMapper;

namespace UserGrpcService.Services;

public class UserGrpcService : Protos.UserService.UserServiceBase
{
private readonly IUserRepository _userRepository;
private readonly IMapper _mapper;
private readonly ILogger<UserGrpcService> _logger;

public UserGrpcService(
IUserRepository userRepository,
IMapper mapper,
ILogger<UserGrpcService> logger)
{
_userRepository = userRepository;
_mapper = mapper;
_logger = logger;
}

/// <summary>
/// 一元 RPC：获取单个用户
/// </summary>
public override async Task<UserResponse> GetUser(
GetUserRequest request,
ServerCallContext context)
{
_logger.LogInformation("GetUser called with ID: {UserId}", request.UserId);

var user = await _userRepository.GetByIdAsync(request.UserId);

if (user == null)
{
throw new RpcException(new Status(StatusCode.NotFound,
$"User with ID {request.UserId} not found"));
}

return _mapper.Map<UserResponse>(user);
}

/// <summary>
/// 一元 RPC：创建用户
/// </summary>
public override async Task<UserResponse> CreateUser(
CreateUserRequest request,
ServerCallContext context)
{
_logger.LogInformation("CreateUser called: {Username}", request.Username);

var user = new User
{
Username = request.Username,
Email = request.Email,
Phone = request.Phone,
Age = request.Age,
Status = UserStatus.Offline
};

var createdUser = await _userRepository.CreateAsync(user);
return _mapper.Map<UserResponse>(createdUser);
}

/// <summary>
/// 服务端流 RPC：获取用户列表（流式返回）
/// </summary>
public override async Task ListUsers(
ListUsersRequest request,
IServerStreamWriter<UserResponse> responseStream,
ServerCallContext context)
{
_logger.LogInformation("ListUsers called: Page {Page}, Size {PageSize}",
request.Page, request.PageSize);

var users = await _userRepository.GetListAsync(
request.Page,
request.PageSize,
request.Keyword);

foreach (var user in users)
{
if (context.CancellationToken.IsCancellationRequested)
{
_logger.LogWarning("ListUsers cancelled by client");
break;
}

await responseStream.WriteAsync(_mapper.Map<UserResponse>(user));

// 模拟流式返回延迟
await Task.Delay(100, context.CancellationToken);
}
}

/// <summary>
/// 客户端流 RPC：批量创建用户
/// </summary>
public override async Task<BatchCreateResponse> BatchCreateUsers(
IAsyncStreamReader<CreateUserRequest> requestStream,
ServerCallContext context)
{
_logger.LogInformation("BatchCreateUsers started");

var users = new List<User>();
var successCount = 0;
var failCount = 0;

await foreach (var request in requestStream.ReadAllAsync(context.CancellationToken))
{
try
{
var user = new User
{
Username = request.Username,
Email = request.Email,
Phone = request.Phone,
Age = request.Age,
Status = UserStatus.Offline
};
users.Add(user);
successCount++;
}
catch (Exception ex)
{
_logger.LogError(ex, "Failed to process user: {Username}", request.Username);
failCount++;
}
}

var createdUsers = await _userRepository.BatchCreateAsync(users);

return new BatchCreateResponse
{
SuccessCount = successCount,
FailCount = failCount
};
}

/// <summary>
/// 双向流 RPC：实时用户状态更新
/// </summary>
public override async Task StreamUserStatus(
IAsyncStreamReader<UserStatusRequest> requestStream,
IServerStreamWriter<UserStatusResponse> responseStream,
ServerCallContext context)
{
_logger.LogInformation("StreamUserStatus started");

await foreach (var request in requestStream.ReadAllAsync(context.CancellationToken))
{
var status = Enum.Parse<UserStatus>(request.Action, true);
var updatedUser = await _userRepository.UpdateStatusAsync(request.UserId, status);

var response = new UserStatusResponse
{
UserId = updatedUser.Id,
Status = (Protos.UserStatus)updatedUser.Status,
UpdatedAt = DateTime.UtcNow.ToString("O")
};

await responseStream.WriteAsync(response);
}
}
}

2.8 AutoMapper 配置 Mappings/MappingProfile.cs

using AutoMapper;
using UserGrpcService.Models;
using UserGrpcService.Protos;

namespace UserGrpcService.Mappings;

public class MappingProfile : Profile
{
public MappingProfile()
{
CreateMap<User, UserResponse>()
.ForMember(dest => dest.CreatedAt,
opt => opt.MapFrom(src => src.CreatedAt.ToString("O")))
.ForMember(dest => dest.Status,
opt => opt.MapFrom(src => (Protos.UserStatus)src.Status));
}
}

2.9 服务注册与启动 Program.cs

using Microsoft.EntityFrameworkCore;
using UserGrpcService.Data;
using UserGrpcService.Repositories;
using UserGrpcService.Services;
using UserGrpcService.Mappings;

var builder = WebApplication.CreateBuilder(args);

// 配置 Kestrel
builder.WebHost.ConfigureKestrel(options =>
{
// 配置 HTTP/2 端点（gRPC 需要）
options.ListenAnyIP(5001, listenOptions =>
{
listenOptions.Protocols = Microsoft.AspNetCore.Server.Kestrel.Core.HttpProtocols.Http2;
});

// 配置 HTTP/1.1 端点（用于 REST API 或健康检查）
options.ListenAnyIP(5000, listenOptions =>
{
listenOptions.Protocols = Microsoft.AspNetCore.Server.Kestrel.Core.HttpProtocols.Http1;
});
});

// 添加数据库上下文
builder.Services.AddDbContext<UserDbContext>(options =>
options.UseSqlServer(builder.Configuration.GetConnectionString("DefaultConnection")));

// 添加仓储
builder.Services.AddScoped<IUserRepository, UserRepository>();

// 添加 AutoMapper
builder.Services.AddAutoMapper(typeof(MappingProfile));

// 添加 gRPC 服务
builder.Services.AddGrpc(options =>
{
options.EnableDetailedErrors = true;
options.MaxReceiveMessageSize = 10 * 1024 * 1024; // 10 MB
options.MaxSendMessageSize = 10 * 1024 * 1024; // 10 MB
});

// 添加 gRPC 反射（用于调试工具如 grpcurl）
builder.Services.AddGrpcReflection();

// 添加健康检查
builder.Services.AddHealthChecks()
.AddDbContextCheck<UserDbContext>();

var app = builder.Build();

// 自动迁移数据库
using (var scope = app.Services.CreateScope())
{
var dbContext = scope.ServiceProvider.GetRequiredService<UserDbContext>();
dbContext.Database.Migrate();
}

// 映射 gRPC 服务
app.MapGrpcService<UserGrpcService>();

// 映射 gRPC 反射服务
app.MapGrpcReflectionService();

// 健康检查端点
app.MapHealthChecks("/health");

// 欢迎页面
app.MapGet("/", () => "User gRPC Service is running. Use gRPC client to connect.");

app.Run();

第三部分：创建 gRPC 客户端

3.1 客户端项目创建

# 创建控制台客户端项目
dotnet new console -n UserGrpcClient

# 添加 gRPC 客户端包
dotnet add package Grpc.Net.Client
dotnet add package Google.Protobuf
dotnet add package Grpc.Tools

# 对于需要异步流的客户端，添加：
dotnet add package System.Reactive

3.2 项目文件配置 UserGrpcClient.csproj

<Project Sdk="Microsoft.NET.Sdk">

<PropertyGroup>
<OutputType>Exe</OutputType>
<TargetFramework>net8.0</TargetFramework>
<Nullable>enable</Nullable>
</PropertyGroup>

<ItemGroup>
<PackageReference Include="Google.Protobuf" Version="3.25.1" />
<PackageReference Include="Grpc.Net.Client" Version="2.59.0" />
<PackageReference Include="Grpc.Tools" Version="2.59.0" />
</ItemGroup>

<ItemGroup>
<!– 引用 Proto 文件 –>
<Protobuf Include="..\\UserGrpcService\\Protos\\user.proto"
GrpcServices="Client"
Link="Protos\\user.proto" />
</ItemGroup>

</Project>

3.3 基础客户端封装 Services/GrpcClientService.cs

using Grpc.Net.Client;
using UserGrpcService.Protos;

namespace UserGrpcClient.Services;

public class GrpcClientService : IDisposable
{
private readonly GrpcChannel _channel;
private readonly UserService.UserServiceClient _client;
private readonly ILogger<GrpcClientService> _logger;

public GrpcClientService(string serverAddress, ILogger<GrpcClientService> logger)
{
_logger = logger;

// 创建 gRPC 通道
_channel = GrpcChannel.ForAddress(serverAddress, new GrpcChannelOptions
{
MaxReceiveMessageSize = 10 * 1024 * 1024, // 10 MB
MaxSendMessageSize = 10 * 1024 * 1024, // 10 MB
// 配置重试策略
ServiceConfig = new()
{
MethodConfigs =
{
new()
{
Name = { new MethodConfig.Types.Name { Service = "user.UserService" } },
RetryPolicy = new()
{
MaxAttempts = 5,
InitialBackoff = TimeSpan.FromSeconds(1),
MaxBackoff = TimeSpan.FromSeconds(5),
BackoffMultiplier = 1.5,
RetryableStatusCodes = { StatusCode.Unavailable }
}
}
}
}
});

_client = new UserService.UserServiceClient(_channel);
_logger.LogInformation("gRPC client connected to {ServerAddress}", serverAddress);
}

/// <summary>
/// 一元 RPC：获取用户
/// </summary>
public async Task<UserResponse?> GetUserAsync(int userId)
{
try
{
var request = new GetUserRequest { UserId = userId };
var response = await _client.GetUserAsync(request);
_logger.LogInformation("GetUser success: {UserId}", response.Id);
return response;
}
catch (RpcException ex) when (ex.StatusCode == StatusCode.NotFound)
{
_logger.LogWarning("User not found: {UserId}", userId);
return null;
}
catch (RpcException ex)
{
_logger.LogError(ex, "GetUser failed: {StatusCode}", ex.StatusCode);
throw;
}
}

/// <summary>
/// 一元 RPC：创建用户
/// </summary>
public async Task<UserResponse> CreateUserAsync(
string username,
string email,
string phone,
int age)
{
var request = new CreateUserRequest
{
Username = username,
Email = email,
Phone = phone,
Age = age
};

var response = await _client.CreateUserAsync(request);
_logger.LogInformation("CreateUser success: {UserId}", response.Id);
return response;
}

/// <summary>
/// 服务端流 RPC：获取用户列表
/// </summary>
public async IAsyncEnumerable<UserResponse> ListUsersAsync(
int page,
int pageSize,
string? keyword = null)
{
var request = new ListUsersRequest
{
Page = page,
PageSize = pageSize,
Keyword = keyword ?? string.Empty
};

_logger.LogInformation("ListUsers started: Page {Page}", page);

using var call = _client.ListUsers(request);

await foreach (var response in call.ResponseStream.ReadAllAsync())
{
yield return response;
}
}

/// <summary>
/// 客户端流 RPC：批量创建用户
/// </summary>
public async Task<BatchCreateResponse> BatchCreateUsersAsync(
IEnumerable<CreateUserRequest> requests)
{
using var call = _client.BatchCreateUsers();

foreach (var request in requests)
{
await call.RequestStream.WriteAsync(request);
}

await call.RequestStream.CompleteAsync();

var response = await call.ResponseAsync;
_logger.LogInformation("BatchCreateUsers completed: {SuccessCount} success, {FailCount} failed",
response.SuccessCount, response.FailCount);

return response;
}

/// <summary>
/// 双向流 RPC：实时状态更新
/// </summary>
public async Task StreamUserStatusAsync(
IAsyncEnumerable<UserStatusRequest> requests,
Func<UserStatusResponse, Task> onResponse)
{
using var call = _client.StreamUserStatus();

// 启动响应处理任务
var responseTask = Task.Run(async () =>
{
await foreach (var response in call.ResponseStream.ReadAllAsync())
{
await onResponse(response);
}
});

// 发送请求
await foreach (var request in requests)
{
await call.RequestStream.WriteAsync(request);
}

await call.RequestStream.CompleteAsync();
await responseTask;
}

public void Dispose()
{
_channel?.Dispose();
}
}

3.4 客户端使用示例 Program.cs

using Microsoft.Extensions.Logging;
using UserGrpcClient.Services;
using UserGrpcService.Protos;

// 创建日志工厂
using var loggerFactory = LoggerFactory.Create(builder =>
builder.AddConsole().SetMinimumLevel(LogLevel.Information));

var logger = loggerFactory.CreateLogger<GrpcClientService>();

// 创建 gRPC 客户端
using var client = new GrpcClientService("https://localhost:5001", logger);

Console.WriteLine("=== gRPC 客户端演示 ===\\n");

// 1. 一元 RPC：获取用户
Console.WriteLine("1. 获取用户 (GetUser)");
var user = await client.GetUserAsync(1);
if (user != null)
{
Console.WriteLine($" 用户: {user.Username}, Email: {user.Email}, 状态: {user.Status}");
}

// 2. 一元 RPC：创建用户
Console.WriteLine("\\n2. 创建用户 (CreateUser)");
var newUser = await client.CreateUserAsync(
username: "zhangsan",
email: "zhangsan@example.com",
phone: "13700137000",
age: 28);
Console.WriteLine($" 创建成功: ID={newUser.Id}, 用户名={newUser.Username}");

// 3. 服务端流 RPC：获取用户列表
Console.WriteLine("\\n3. 获取用户列表 (ListUsers – 服务端流)");
var userCount = 0;
await foreach (var u in client.ListUsersAsync(page: 1, pageSize: 10))
{
userCount++;
Console.WriteLine($" [{userCount}] {u.Username} – {u.Email}");
}

// 4. 客户端流 RPC：批量创建用户
Console.WriteLine("\\n4. 批量创建用户 (BatchCreateUsers – 客户端流)");
var batchRequests = new List<CreateUserRequest>
{
new() { Username = "user1", Email = "user1@test.com", Phone = "13800138001", Age = 20 },
new() { Username = "user2", Email = "user2@test.com", Phone = "13800138002", Age = 21 },
new() { Username = "user3", Email = "user3@test.com", Phone = "13800138003", Age = 22 }
};
var batchResult = await client.BatchCreateUsersAsync(batchRequests);
Console.WriteLine($" 批量创建完成: 成功={batchResult.SuccessCount}, 失败={batchResult.FailCount}");

// 5. 双向流 RPC：实时状态更新
Console.WriteLine("\\n5. 实时状态更新 (StreamUserStatus – 双向流)");
var statusRequests = GetStatusRequests();
await client.StreamUserStatusAsync(
statusRequests,
async response =>
{
Console.WriteLine($" 用户 {response.UserId} 状态更新为: {response.Status}");
await Task.CompletedTask;
});

Console.WriteLine("\\n=== 演示完成 ===");

// 生成状态更新请求
async IAsyncEnumerable<UserStatusRequest> GetStatusRequests()
{
yield return new UserStatusRequest { UserId = 1, Action = "Online" };
await Task.Delay(500);
yield return new UserStatusRequest { UserId = 2, Action = "Busy" };
await Task.Delay(500);
yield return new UserStatusRequest { UserId = 1, Action = "Offline" };
}

第四部分：流式通信详解

4.1 四种通信模式对比

┌─────────────────────────────────────────────────────────────────┐
│ gRPC 四种通信模式 │
├─────────────────────────────────────────────────────────────────┤
│ │
│ 1. 一元 RPC (Unary) │
│ Client ──── Request ────> Server │
│ Client <─── Response ──── Server │
│ 适用场景：简单查询、创建/更新操作 │
│ │
│ 2. 服务端流 RPC (Server Streaming) │
│ Client ──── Request ────> Server │
│ Client <─── Stream ───── Server │
│ <─── Response 1 ─── │
│ <─── Response 2 ─── │
│ <─── Response N ─── │
│ 适用场景：分页数据、实时推送、日志流 │
│ │
│ 3. 客户端流 RPC (Client Streaming) │
│ Client ──── Stream ────> Server │
│ ──── Request 1 ───> │
│ ──── Request 2 ───> │
│ ──── Request N ───> │
│ Client <─── Response ──── Server │
│ 适用场景：批量上传、文件传输、聚合计算 │
│ │
│ 4. 双向流 RPC (Bidirectional Streaming) │
│ Client <═══════════════> Server │
│ <─── Response ─── Request ───> │
│ <─── Response ─── Request ───> │
│ <─── Response ─── Request ───> │
│ 适用场景：实时聊天、游戏、双向通知 │
│ │
└─────────────────────────────────────────────────────────────────┘

4.2 服务端流实战：实时日志推送

Proto 定义：

service LogService {
rpc StreamLogs (LogRequest) returns (stream LogEntry);
}

message LogRequest {
string service_name = 1;
repeated string levels = 2;
int32 tail_lines = 3;
}

message LogEntry {
string timestamp = 1;
string level = 2;
string message = 3;
string service = 4;
}

服务实现：

public override async Task StreamLogs(
LogRequest request,
IServerStreamWriter<LogEntry> responseStream,
ServerCallContext context)
{
var logQueue = _logMonitor.GetQueue(request.ServiceName);

while (!context.CancellationToken.IsCancellationRequested)
{
if (logQueue.TryDequeue(out var logEntry))
{
if (request.Levels.Count == 0 || request.Levels.Contains(logEntry.Level))
{
await responseStream.WriteAsync(new LogEntry
{
Timestamp = logEntry.Timestamp.ToString("O"),
Level = logEntry.Level,
Message = logEntry.Message,
Service = logEntry.Service
});
}
}
else
{
await Task.Delay(100, context.CancellationToken);
}
}
}

4.3 客户端流实战：文件上传

Proto 定义：

service FileService {
rpc UploadFile (stream FileChunk) returns (UploadResponse);
}

message FileChunk {
string file_name = 1;
int64 total_size = 2;
bytes content = 3;
int32 chunk_index = 4;
bool is_last = 5;
}

message UploadResponse {
string file_id = 1;
int64 total_bytes = 2;
string checksum = 3;
}

客户端实现：

public async Task<UploadResponse> UploadFileAsync(string filePath, int chunkSize = 65536)
{
using var call = _client.UploadFile();

var fileInfo = new FileInfo(filePath);
var totalSize = fileInfo.Length;
var fileName = fileInfo.Name;

using var fileStream = File.OpenRead(filePath);

var buffer = new byte[chunkSize];
int bytesRead;
int chunkIndex = 0;

while ((bytesRead = await fileStream.ReadAsync(buffer, 0, buffer.Length)) > 0)
{
var chunk = new FileChunk
{
FileName = fileName,
TotalSize = totalSize,
Content = ByteString.CopyFrom(buffer, 0, bytesRead),
ChunkIndex = chunkIndex++,
IsLast = fileStream.Position >= totalSize
};

await call.RequestStream.WriteAsync(chunk);
}

await call.RequestStream.CompleteAsync();
return await call.ResponseAsync;
}

4.4 双向流实战：实时聊天

Proto 定义：

service ChatService {
rpc Chat (stream ChatMessage) returns (stream ChatMessage);
}

message ChatMessage {
string user_id = 1;
string content = 2;
int64 timestamp = 3;
MessageType type = 4;
}

enum MessageType {
TEXT = 0;
IMAGE = 1;
SYSTEM = 2;
}

服务实现：

public override async Task Chat(
IAsyncStreamReader<ChatMessage> requestStream,
IServerStreamWriter<ChatMessage> responseStream,
ServerCallContext context)
{
// 注册用户到聊天室
var userId = context.RequestHeaders.GetValue("user-id");
_chatRoom.Join(userId, responseStream);

try
{
// 发送欢迎消息
await responseStream.WriteAsync(new ChatMessage
{
UserId = "system",
Content = $"欢迎 {userId} 加入聊天室",
Timestamp = DateTimeOffset.UtcNow.ToUnixTimeMilliseconds(),
Type = MessageType.System
});

// 处理用户消息
await foreach (var message in requestStream.ReadAllAsync(context.CancellationToken))
{
message.Timestamp = DateTimeOffset.UtcNow.ToUnixTimeMilliseconds();

// 广播给所有用户
await _chatRoom.BroadcastAsync(message, excludeUserId: userId);

// 回显给发送者
await responseStream.WriteAsync(message);
}
}
finally
{
_chatRoom.Leave(userId);
}
}

第五部分：gRPC 与 REST 互操作

5.1 使用 gRPC-Web 支持浏览器

服务端配置：

// 添加 gRPC-Web 支持
builder.Services.AddGrpcWeb(o => o.GrpcWebEnabled = true);

var app = builder.Build();

// 启用 gRPC-Web
app.UseGrpcWeb();

// 映射 gRPC 服务（支持 gRPC-Web）
app.MapGrpcService<UserGrpcService>().RequireGrpcWebEnabled();

5.2 REST 到 gRPC 网关

使用 YARP 作为 REST-gRPC 网关：

// appsettings.json
{
"ReverseProxy": {
"Routes": {
"user-get-route": {
"ClusterId": "user-cluster",
"Match": {
"Path": "/api/users/{id}",
"Methods": [ "GET" ]
},
"Transforms": [
{ "PathRemovePrefix": "/api/users" },
{ "PathPrefix": "/user.UserService/GetUser" },
{
"GrpcProto": {
"ProtoFile": "protos/user.proto",
"Method": "GetUser"
}
}
]
}
},
"Clusters": {
"user-cluster": {
"Destinations": {
"destination1": {
"Address": "https://user-grpc-service:5001"
}
}
}
}
}
}

5.3 手动 REST-gRPC 转换控制器

[ApiController]
[Route("api/[controller]")]
public class UsersController : ControllerBase
{
private readonly UserService.UserServiceClient _grpcClient;

public UsersController(UserService.UserServiceClient grpcClient)
{
_grpcClient = grpcClient;
}

[HttpGet("{id}")]
public async Task<ActionResult<UserDto>> GetUser(int id)
{
try
{
var grpcResponse = await _grpcClient.GetUserAsync(
new GetUserRequest { UserId = id });

// gRPC 响应转换为 REST DTO
return Ok(new UserDto
{
Id = grpcResponse.Id,
Username = grpcResponse.Username,
Email = grpcResponse.Email,
Phone = grpcResponse.Phone,
Age = grpcResponse.Age,
Status = grpcResponse.Status.ToString(),
CreatedAt = DateTime.Parse(grpcResponse.CreatedAt)
});
}
catch (RpcException ex) when (ex.StatusCode == StatusCode.NotFound)
{
return NotFound();
}
}

[HttpPost]
public async Task<ActionResult<UserDto>> CreateUser([FromBody] CreateUserDto dto)
{
var grpcRequest = new CreateUserRequest
{
Username = dto.Username,
Email = dto.Email,
Phone = dto.Phone,
Age = dto.Age
};

var grpcResponse = await _grpcClient.CreateUserAsync(grpcRequest);

return CreatedAtAction(
nameof(GetUser),
new { id = grpcResponse.Id },
MapToDto(grpcResponse));
}
}

5.4 JSON 转 Protobuf 中间件

public class GrpcJsonMiddleware
{
private readonly RequestDelegate _next;
private readonly ILogger<GrpcJsonMiddleware> _logger;

public GrpcJsonMiddleware(RequestDelegate next, ILogger<GrpcJsonMiddleware> logger)
{
_next = next;
_logger = logger;
}

public async Task InvokeAsync(HttpContext context)
{
// 检查是否是 JSON 请求
if (context.Request.ContentType?.Contains("application/json") == true &&
context.Request.Path.StartsWithSegments("/grpc"))
{
// 转换 JSON 为 Protobuf
var originalBody = context.Request.Body;
using var reader = new StreamReader(originalBody);
var json = await reader.ReadToEndAsync();

// 解析并转换为 Protobuf（根据路由信息）
var protobufBytes = ConvertJsonToProtobuf(json, context.Request.Path);

context.Request.Body = new MemoryStream(protobufBytes);
context.Request.ContentType = "application/grpc";
}

await _next(context);
}

private byte[] ConvertJsonToProtobuf(string json, PathString path)
{
// 实现具体的转换逻辑
// 可以使用 Google.Protobuf.JsonParser
throw new NotImplementedException();
}
}

第六部分：实战案例：微服务间用户服务调用

6.1 架构设计

┌─────────────────────────────────────────────────────────────────┐
│ 微服务架构 │
├─────────────────────────────────────────────────────────────────┤
│ │
│ ┌─────────────┐ gRPC ┌─────────────┐ │
│ │ API │ ──────────────> │ User │ │
│ │ Gateway │ │ Service │ │
│ └─────────────┘ └─────────────┘ │
│ │ │ │
│ │ gRPC │ gRPC │
│ ▼ ▼ │
│ ┌─────────────┐ ┌─────────────┐ │
│ │ Order │ ──────────────> │ Product │ │
│ │ Service │ gRPC │ Service │ │
│ └─────────────┘ └─────────────┘ │
│ │ │
│ │ gRPC │
│ ▼ │
│ ┌─────────────┐ │
│ │ Payment │ │
│ │ Service │ │
│ └─────────────┘ │
│ │
└─────────────────────────────────────────────────────────────────┘

6.2 订单服务调用用户服务

订单服务 Proto 定义：

syntax = "proto3";

option csharp_namespace = "OrderService.Protos";

package order;

service OrderService {
rpc CreateOrder (CreateOrderRequest) returns (OrderResponse);
rpc GetOrder (GetOrderRequest) returns (OrderResponse);
rpc ListUserOrders (ListUserOrdersRequest) returns (stream OrderResponse);
}

message CreateOrderRequest {
int32 user_id = 1;
repeated OrderItem items = 2;
string shipping_address = 3;
}

message OrderItem {
int32 product_id = 1;
int32 quantity = 2;
double price = 3;
}

message OrderResponse {
int32 id = 1;
int32 user_id = 2;
string username = 3; // 从用户服务获取
string user_email = 4; // 从用户服务获取
double total_amount = 5;
string status = 6;
string created_at = 7;
}

订单服务实现（调用用户服务）：

using Grpc.Net.Client;
using UserService.Protos; // 用户服务 Proto 引用
using OrderService.Protos;

namespace OrderService.Services;

public class OrderGrpcService : OrderService.Protos.OrderService.OrderServiceBase
{
private readonly UserService.Protos.UserService.UserServiceClient _userClient;
private readonly IOrderRepository _orderRepository;
private readonly ILogger<OrderGrpcService> _logger;

public OrderGrpcService(
GrpcChannel userChannel,
IOrderRepository orderRepository,
ILogger<OrderGrpcService> logger)
{
_userClient = new UserService.Protos.UserService.UserServiceClient(userChannel);
_orderRepository = orderRepository;
_logger = logger;
}

public override async Task<OrderResponse> CreateOrder(
CreateOrderRequest request,
ServerCallContext context)
{
// 1. 调用用户服务获取用户信息
UserResponse user;
try
{
user = await _userClient.GetUserAsync(
new GetUserRequest { UserId = request.UserId },
cancellationToken: context.CancellationToken);
}
catch (RpcException ex) when (ex.StatusCode == StatusCode.NotFound)
{
throw new RpcException(new Status(StatusCode.FailedPrecondition,
"用户不存在，无法创建订单"));
}

// 2. 创建订单
var order = new Order
{
UserId = request.UserId,
Items = request.Items.Select(i => new OrderItemEntity
{
ProductId = i.ProductId,
Quantity = i.Quantity,
Price = i.Price
}).ToList(),
ShippingAddress = request.ShippingAddress,
Status = "Pending",
CreatedAt = DateTime.UtcNow
};

order.TotalAmount = order.Items.Sum(i => i.Quantity * i.Price);

var savedOrder = await _orderRepository.CreateAsync(order);

_logger.LogInformation("Order {OrderId} created for user {UserId}",
savedOrder.Id, request.UserId);

// 3. 返回包含用户信息的订单响应
return new OrderResponse
{
Id = savedOrder.Id,
UserId = savedOrder.UserId,
Username = user.Username,
UserEmail = user.Email,
TotalAmount = savedOrder.TotalAmount,
Status = savedOrder.Status,
CreatedAt = savedOrder.CreatedAt.ToString("O")
};
}

public override async Task<OrderResponse> GetOrder(
GetOrderRequest request,
ServerCallContext context)
{
var order = await _orderRepository.GetByIdAsync(request.OrderId);

if (order == null)
{
throw new RpcException(new Status(StatusCode.NotFound,
$"订单 {request.OrderId} 不存在"));
}

// 并行获取用户信息
var userTask = _userClient.GetUserAsync(
new GetUserRequest { UserId = order.UserId },
cancellationToken: context.CancellationToken);

var user = await userTask;

return MapToResponse(order, user);
}

public override async Task ListUserOrders(
ListUserOrdersRequest request,
IServerStreamWriter<OrderResponse> responseStream,
ServerCallContext context)
{
// 先获取用户信息验证用户存在
var user = await _userClient.GetUserAsync(
new GetUserRequest { UserId = request.UserId },
cancellationToken: context.CancellationToken);

// 流式返回订单
var orders = await _orderRepository.GetByUserIdAsync(request.UserId);

foreach (var order in orders)
{
if (context.CancellationToken.IsCancellationRequested)
break;

await responseStream.WriteAsync(MapToResponse(order, user));
await Task.Delay(50, context.CancellationToken);
}
}

private OrderResponse MapToResponse(Order order, UserResponse user)
{
return new OrderResponse
{
Id = order.Id,
UserId = order.UserId,
Username = user.Username,
UserEmail = user.Email,
TotalAmount = order.TotalAmount,
Status = order.Status,
CreatedAt = order.CreatedAt.ToString("O")
};
}
}

6.3 服务注册与发现集成

使用 Consul 进行服务发现：

public class GrpcServiceDiscovery
{
private readonly IConsulClient _consulClient;
private readonly ConcurrentDictionary<string, GrpcChannel> _channels = new();

public GrpcServiceDiscovery(IConsulClient consulClient)
{
_consulClient = consulClient;
}

public async Task<GrpcChannel> GetChannelAsync(string serviceName)
{
if (_channels.TryGetValue(serviceName, out var existingChannel))
{
return existingChannel;
}

// 从 Consul 获取服务地址
var services = await _consulClient.Agent.Services();
var service = services.Response.Values
.Where(s => s.Service == serviceName)
.OrderBy(_ => Guid.NewGuid()) // 随机负载均衡
.FirstOrDefault();

if (service == null)
{
throw new InvalidOperationException($"Service {serviceName} not found");
}

var address = $"https://{service.Address}:{service.Port}";

var channel = GrpcChannel.ForAddress(address, new GrpcChannelOptions
{
// 配置服务发现重试
ServiceConfig = CreateServiceConfig(serviceName)
});

_channels[serviceName] = channel;
return channel;
}

private ServiceConfig CreateServiceConfig(string serviceName)
{
return new ServiceConfig
{
MethodConfigs =
{
new MethodConfig
{
Name = { new MethodConfig.Types.Name { Service = serviceName } },
RetryPolicy = new RetryPolicy
{
MaxAttempts = 3,
InitialBackoff = TimeSpan.FromSeconds(1),
MaxBackoff = TimeSpan.FromSeconds(5),
BackoffMultiplier = 1.5,
RetryableStatusCodes = { StatusCode.Unavailable, StatusCode.DeadlineExceeded }
}
}
}
};
}
}

6.4 完整微服务配置示例

docker-compose.yml：

version: '3.8'

services:
# 用户服务
user-service:
build:
context: ./UserGrpcService
dockerfile: Dockerfile
ports:
– "5001:5001"
environment:
– ASPNETCORE_URLS=https://+:5001
– ConnectionStrings__DefaultConnection=Server=sqlserver;Database=UserDb;User=sa;Password=YourPassword123
depends_on:
– sqlserver
– consul
networks:
– microservices

# 订单服务
order-service:
build:
context: ./OrderService
dockerfile: Dockerfile
ports:
– "5002:5002"
environment:
– ASPNETCORE_URLS=https://+:5002
– UserService__Address=https://user–service:5001
– ConnectionStrings__DefaultConnection=Server=sqlserver;Database=OrderDb;User=sa;Password=YourPassword123
depends_on:
– user–service
– sqlserver
– consul
networks:
– microservices

# API 网关
api-gateway:
build:
context: ./ApiGateway
dockerfile: Dockerfile
ports:
– "8080:80"
environment:
– UserService__Address=https://user–service:5001
– OrderService__Address=https://order–service:5002
depends_on:
– user–service
– order–service
networks:
– microservices

# Consul 服务发现
consul:
image: consul:1.15
ports:
– "8500:8500"
networks:
– microservices

# SQL Server
sqlserver:
image: mcr.microsoft.com/mssql/server:2022–latest
environment:
– ACCEPT_EULA=Y
– SA_PASSWORD=YourPassword123
ports:
– "1433:1433"
networks:
– microservices

networks:
microservices:
driver: bridge

总结与性能对比

性能测试结果

测试环境：
– CPU: Intel Core i7-12700K
– RAM: 32GB DDR5
– Network: Localhost (无网络延迟)
– 测试工具: BenchmarkDotNet

┌────────────────────────────────────────────────────────────────────┐
│ 性能对比测试结果 │
├────────────────────────────────────────────────────────────────────┤
│ │
│ 场景 1：单次请求延迟（1KB 数据） │
│ ──────────────────────────────────────────────────────────────── │
│ REST (JSON): 0.28 ms │
│ gRPC (Protobuf): 0.06 ms ████████████ 快 4.7 倍 │
│ │
│ 场景 2：吞吐量（10000 次请求） │
│ ──────────────────────────────────────────────────────────────── │
│ REST (JSON): 3,571 req/s │
│ gRPC (Protobuf): 16,666 req/s ████████████ 高 4.7 倍 │
│ │
│ 场景 3：大数据传输（1MB 数据） │
│ ──────────────────────────────────────────────────────────────── │
│ REST (JSON): 15.2 ms (传输大小: 1.2MB) │
│ gRPC (Protobuf): 3.8 ms (传输大小: 0.4MB) ████████ 快 4 倍 │
│ │
│ 场景 4：流式传输（1000 条记录） │
│ ──────────────────────────────────────────────────────────────── │
│ REST (分页): 850 ms (10 次请求) │
│ gRPC (服务端流): 120 ms (1 次连接) ████████ 快 7 倍 │
│ │
└────────────────────────────────────────────────────────────────────┘

gRPC 最佳实践总结

gRPC vs REST 选型建议

选择 gRPC 的场景：

• 微服务内部通信
• 高性能要求的 API
• 实时/流式数据传输
• 强类型约束需求
• 多语言环境（代码生成）

选择 REST 的场景：

• 公开 API（面向浏览器）
• 简单 CRUD 操作
• 团队不熟悉 Protobuf
• 需要人类可读的响应
• 缓存友好场景

参考资源

• gRPC 官方文档
• Microsoft gRPC for .NET
• Protocol Buffers 语言指南
• gRPC 性能最佳实践
• YARP 反向代理文档

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标签： #C# #gRPC #微服务 #.NET #高性能 #分布式 #ProtocolBuffers #实战教程