配置Apache Camel 4.1.0实现Trace ID与Span ID打印及路由传递

问题现象 #

使用Apache Camel 4.1.0集成OpenTelemetry，已添加依赖、启用MDC日志并完成配置，但调用路由时日志中的Trace ID和Span ID均显示为全0值，无法实现跨路由的Trace/Span传递与打印。

日志示例：

INFO [service,00000000000000000000000000000000,0000000000000000] 476 --- [14 - Aggregator] eamRoute : Total time taken for batch insertion: 0 seconds
INFO [payment-service,00000000000000000000000000000000,0000000000000000] 476 --- [ormAndSendRoute] message-producer : Request body sending to API:

已完成的配置 #

添加依赖 #

<dependency>
    <groupId>org.apache.camel.springboot</groupId>
    <artifactId>camel-opentelemetry-starter</artifactId>
    <version>${camel.version}</version>
</dependency>

application.yml配置 #

springboot:
    main-run-controller: true
    use-mdc-logging: true
    mdc-logging-keys-pattern: "*"

logging:
  file:
    name: '${logging.file.path}/app.log'
    path: ./logs
  pattern:
    level: "%5p [${spring.application.name:},%X{trace_id:-},%X{span_id:-}]"

Spring Boot代码 #

@SpringBootApplication
@CamelOpenTelemetry
public class TraceIdApplication {

    public static void main(String[] args) {
        SpringApplication.run(TraceIdApplication.class, args);
    }
}

@Component
public class CamelTraceId extends RouteBuilder  {

    @Override
    public void configure() throws Exception {
        from("timer://foo?fixedRate=true&delay=0&period=2000")
                .log("in timer")
                .to("direct:traceLogging")
                .end();

        from("direct:traceLogging")
                .to("direct:restfulcall")
                .log("testing").end();
    }
}

解决方案 #

1. 修正MDC日志键名匹配 #

Camel的OpenTelemetry集成在MDC中注入的Trace/Span键名为traceId和spanId，而非配置中的trace_id和span_id。修改日志pattern：

logging:
  pattern:
    level: "%5p [${spring.application.name:},%X{traceId:-},%X{spanId:-}]"

2. 显式启用OpenTelemetry并配置采样策略 #

在application.yml中添加OpenTelemetry相关配置，确保采样策略为全采样，避免因采样率为0导致无Trace/Span生成：

camel:
  opentelemetry:
    enabled: true
    tracing-mode: active # 主动追踪所有路由节点
otel:
  traces:
    sampler: always_on # 全采样，确保所有请求生成Trace/Span

3. 确保路由操作被Span覆盖（可选） #

对于Timer这类定时触发的组件，可显式在路由中开启Span，确保追踪生效：

@Override
public void configure() throws Exception {
    from("timer://foo?fixedRate=true&delay=0&period=2000")
            .startSpan("timer-init-span") // 显式启动根Span
            .log("in timer")
            .to("direct:traceLogging")
            .end();

    from("direct:traceLogging")
            .startSpan("trace-logging-span") // 启动子Span
            .to("direct:restfulcall")
            .log("testing")
            .end();
}

验证结果 #

重启应用后，日志中应显示正常的非全0 Trace ID和Span ID，且跨路由调用时Trace ID保持一致，Span ID随路由节点切换。

内容的提问来源于stack exchange，提问作者Charan