程序员练级攻略：微服务-[2026重制版]

// user.proto
syntax = "proto3";
package user.v1;

option go_package = "github.com/example/api/gen/go/user/v1;userv1";

service UserService {
  // RPC 定义
  rpc GetUser(GetUserRequest) returns (GetUserResponse);
  rpc CreateUser(CreateUserRequest) returns (CreateUserResponse);
  rpc ListUsers(ListUsersRequest) returns (stream User);  // 服务端流
}

message GetUserRequest {
  string user_id = 1;
}

message GetUserResponse {
  User user = 1;
}

message User {
  string id = 1;
  string name = 2;
  string email = 3;
  repeated string roles = 4;  // 数组
  google.protobuf.Timestamp created_at = 5;  // 时间戳
}

# 伪代码示例：Outbox Pattern 实现
import sqlalchemy as db

def create_order(order_data):
    with db.session.begin():  # 本地事务
        # 1. 写入业务表
        order = Order(**order_data)
        session.add(order)
        
        # 2. 写入Outbox表（同一事务）
        outbox = Outbox(
            aggregate_type="Order",
            aggregate_id=order.id,
            event_type="OrderCreated",
            payload=json.dumps({
                "order_id": str(order.id),
                "user_id": order.user_id,
                "amount": order.amount
            })
        )
        session.add(outbox)
    # 事务提交后，两者原子性保证

# 后台轮询或CDC将outbox消息发布到消息队列
def poll_outbox():
    unpolled = session.query(Outbox).filter(Outbox.processed == False).limit(100)
    for msg in unpolled:
        kafka_producer.send("order-events", msg.payload)
        msg.processed = True
        session.commit()

// 1. 引入依赖 (build.gradle)
dependencies {
    implementation 'org.springframework.cloud:spring-cloud-starter-bootstrap'
    implementation 'com.alibaba.cloud:spring-cloud-starter-alibaba-nacos-discovery'
    implementation 'com.alibaba.cloud:spring-cloud-starter-alibaba-nacos-config'
}

// 2. bootstrap.yml
spring:
  application:
    name: user-service
  cloud:
    nacos:
      discovery:
        server-addr: ${NACOS_HOST:nacos}:8848
      config:
        server-addr: ${NACOS_HOST:nacos}:8848
        file-extension: yaml
        shared-configs:
          - data-id: common.yaml
            group: DEFAULT_GROUP
            refresh: true

// 3. 主启动类
@SpringBootApplication
@EnableDiscoveryClient
public class UserServiceApplication {
    public static void main(String[] args) {
        SpringApplication.run(UserServiceApplication.class, args);
    }
}