Spring Boot 3+Micrometer下如何为CommandLineRunner开启Trace-ID上下文传播？

方法1：使用 @Observed 注解自动管理追踪上下文 #

Micrometer Tracing 在 Spring Boot 3 中基于 Observation API 实现追踪，CommandLineRunner 不像 Web 请求那样有自动的上下文初始化，需要通过 @Observed 注解显式触发追踪上下文的创建：

修改你的 JobRunner 类：

import io.micrometer.observation.annotation.Observed;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.boot.CommandLineRunner;
import org.springframework.stereotype.Component;

@Component
public class JobRunner implements CommandLineRunner {
    private static final Logger log = LoggerFactory.getLogger(JobRunner.class);
    private final PetsJobExecutor petsJobExecutor;

    public JobRunner(PetsJobExecutor petsJobExecutor) {
        this.petsJobExecutor = petsJobExecutor;
    }

    @Observed(name = "job.run", contextualName = "pets-update-job")
    @TrackExecutionTime
    @Override
    public void run(String... args) {
        log.info("Started the job");
        petsJobExecutor.updatePets();
        log.info("Finished the job");
    }
}

• @Observed 会自动为方法创建一个追踪 Span，初始化 Trace-ID 上下文，日志中的 %X{traceId} 就能正常输出。
• name 和 contextualName 用于标识这个追踪任务，方便在监控系统中区分。

方法2：手动初始化追踪上下文（适合更灵活的场景） #

如果需要更精细的控制，可以通过 ObservationRegistry 手动启动一个 Observation 来包裹业务逻辑：

import io.micrometer.observation.Observation;
import io.micrometer.observation.ObservationRegistry;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.boot.CommandLineRunner;
import org.springframework.stereotype.Component;

@Component
public class JobRunner implements CommandLineRunner {
    private static final Logger log = LoggerFactory.getLogger(JobRunner.class);
    private final PetsJobExecutor petsJobExecutor;
    private final ObservationRegistry observationRegistry;

    public JobRunner(PetsJobExecutor petsJobExecutor, ObservationRegistry observationRegistry) {
        this.petsJobExecutor = petsJobExecutor;
        this.observationRegistry = observationRegistry;
    }

    @TrackExecutionTime
    @Override
    public void run(String... args) {
        Observation.createNotStarted("job.run", observationRegistry)
                .contextualName("pets-update-job")
                .observe(() -> {
                    log.info("Started the job");
                    petsJobExecutor.updatePets();
                    log.info("Finished the job");
                });
    }
}

这种方式手动控制追踪上下文的生命周期，适合需要在代码中自定义 Span 内容的场景。

必要的依赖检查 #

确保你的项目中已经引入了 Micrometer Tracing 的相关依赖（以 Brave 为例）：

<!-- pom.xml -->
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-actuator</artifactId>
</dependency>
<dependency>
    <groupId>io.micrometer</groupId>
    <artifactId>micrometer-tracing-bridge-brave</artifactId>
</dependency>

如果使用 Gradle，对应依赖如下：

// build.gradle
implementation 'org.springframework.boot:spring-boot-starter-actuator'
implementation 'io.micrometer:micrometer-tracing-bridge-brave'

日志配置确认 #

虽然你的 Rest 控制器已经能输出 Trace-ID，还是确认下日志格式配置（以 logback 为例），确保包含 Trace-ID 和 Span-ID：

<!-- logback-spring.xml -->
<pattern>%d{yyyy-MM-dd HH:mm:ss.SSS} [%thread] %-5level %logger{36} %X{traceId:-} %X{spanId:-} - %msg%n</pattern>

内容的提问来源于stack exchange，提问作者MariaLO