使用CompletableFuture时Tracing Context未传播的问题排查求助

你的问题核心是手动构建的ContextSnapshotFactory没有包含Micrometer追踪上下文的传播器，导致捕获的上下文快照里没有TraceContext，异步线程无法获取到追踪信息。

解决方法 #

方案1：使用Spring自动配置的ContextSnapshotFactory

Spring Boot已经为我们配置好了包含TraceContext传播器的ContextSnapshotFactory，直接注入使用即可：

@Autowired
private ContextSnapshotFactory contextSnapshotFactory;

@Test
void testContextPropagation() throws ExecutionException, InterruptedException {
    // 使用try-with-resources确保Span自动结束
    try (ScopedSpan scopedSpan = tracer.startScopedSpan("trigger the creation of a new trace...")) {
        logger.info("CONTEXT: {}", tracer.currentTraceContext().context());
        Executor wrappedExecutor = contextSnapshotFactory.captureAll().wrapExecutor(Executors.newSingleThreadExecutor());
        CompletableFuture.supplyAsync(() -> {
            logger.info("CONTEXT: {}", tracer.currentTraceContext().context());
            return null;
        }, wrappedExecutor).get();
    }
}

方案2：手动为ContextSnapshotFactory添加TraceContext传播器

如果必须手动构建工厂，需要显式添加TraceContextPropagator：

@Test
void testContextPropagation() throws ExecutionException, InterruptedException {
    try (ScopedSpan scopedSpan = tracer.startScopedSpan("trigger the creation of a new trace...")) {
        logger.info("CONTEXT: {}", tracer.currentTraceContext().context());
        ContextSnapshotFactory factory = ContextSnapshotFactory.builder()
                .propagators(TraceContextPropagator.getInstance())
                .build();
        Executor wrappedExecutor = factory.captureAll().wrapExecutor(Executors.newSingleThreadExecutor());
        CompletableFuture.supplyAsync(() -> {
            logger.info("CONTEXT: {}", tracer.currentTraceContext().context());
            return null;
        }, wrappedExecutor).get();
    }
}

补充说明 #

• 建议用try-with-resources管理ScopedSpan，避免因异常导致Span无法正常结束，影响追踪数据准确性。
• 若需要传播Baggage，上述两种方案同样适用，因为TraceContextPropagator已经包含了Baggage的传播逻辑。

内容的提问来源于stack exchange，提问作者François Rosière