# 使用 Docker 運(yùn)行 Zipkin
docker run -d -p 9411:9411 --name zipkin openzipkin/zipkin
# 或者使用命令行啟動(dòng)（需要 Java 環(huán)境）
# curl -sSL https://zipkin.io/quickstart.sh | bash -s
# java -jar zipkin.jar

<!-- Spring Cloud 版本管理 -->
<properties>
    <spring-cloud.version>2022.0.4</spring-cloud.version>
</properties>
<!-- Sleuth + Zipkin 依賴 -->
<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-sleuth</artifactId>
</dependency>
<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-sleuth-zipkin</artifactId>
</dependency>

spring:
  application:
    name: user-service
  sleuth:
    sampler:
      probability: 1.0  # 采樣率，1.0表示100%采樣
  zipkin:
    base-url: http://localhost:9411  # Zipkin服務(wù)器地址
    sender:
      type: web

@RestController
@RequestMapping("/users")
public class UserController {
    private final RestTemplate restTemplate;
    private final UserService userService;
    public UserController(RestTemplate restTemplate, UserService userService) {
        this.restTemplate = restTemplate;
        this.userService = userService;
    }
    @GetMapping("/{userId}/orders")
    public UserOrderInfo getUserOrders(@PathVariable Long userId) {
        // Sleuth會(huì)自動(dòng)在header中添加Trace信息
        ResponseEntity<OrderList> orderResponse = restTemplate.exchange(
            "http://order-service/orders/user/" + userId,
            HttpMethod.GET,
            null,
            OrderList.class
        );
        User user = userService.getUserById(userId);
        return new UserOrderInfo(user, orderResponse.getBody());
    }
}

@Service
public class UserService {
    private final Tracer tracer;
    public UserService(Tracer tracer) {
        this.tracer = tracer;
    }
    public User getUserById(Long userId) {
        // 創(chuàng)建自定義Span
        Span userSpan = tracer.nextSpan().name("db.user.query").start();
        try (Tracer.SpanInScope ws = tracer.withSpanInScope(userSpan)) {
            // 業(yè)務(wù)邏輯
            userSpan.tag("user.id", userId.toString());
            userSpan.event("query.user.from.database");
            // 模擬數(shù)據(jù)庫(kù)查詢
            return userRepository.findById(userId);
        } catch (Exception e) {
            userSpan.error(e);
            throw e;
        } finally {
            userSpan.end();
        }
    }
}

@Async
@Sleuth
public CompletableFuture<User> getUserAsync(Long userId) {
    // Sleuth會(huì)自動(dòng)傳遞Trace上下文
    return CompletableFuture.supplyAsync(() -> userRepository.findById(userId));
}

@Configuration
public class TraceConfig {
    @Bean
    public Sampler defaultSampler() {
        // 自定義采樣策略：只追蹤重要接口
        return new Sampler() {
            @Override
            public boolean isSampled(TraceContext traceContext) {
                // 根據(jù)請(qǐng)求路徑?jīng)Q定是否采樣
                String path = getCurrentRequestPath();
                return path.startsWith("/api/") || path.startsWith("/internal/");
            }
        };
    }
}

@Configuration
public class DataSourceConfig {
    @Bean
    public DataSource dataSource() {
        // 使用P6Spy攔截SQL語(yǔ)句
        P6SpyDataSource dataSource = new P6SpyDataSource(actualDataSource());
        return dataSource;
    }
}

@Component
public class MessageService {
    private final Tracer tracer;
    private final StreamBridge streamBridge;
    public void sendUserCreatedEvent(User user) {
        // 手動(dòng)注入Trace信息到消息頭
        Message<User> message = MessageBuilder.withPayload(user)
            .setHeader("traceId", tracer.currentSpan().context().traceId())
            .setHeader("spanId", tracer.currentSpan().context().spanId())
            .build();
        streamBridge.send("user-created-out-0", message);
    }
}