[CAMEL-19124] Tracer doesn't continue spans for AbstractInternalSpanDecorator

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 3.20.2, 3.x, 4.0.0
• Fix Version/s: 3.21.0, 4.0-M3, 4.0.0
• Component/s: camel-tracing
• Estimated Complexity: Unknown
• Assignee: Unassigned
• Reporter: Marcin Grzejszczak
• Created: 07/Mar/23 15:50
• Updated: 27/Mar/23 10:03
• Resolved: 27/Mar/23 10:03

Description

As discussed in the PR it seems that the `Tracer`component from `camel-tracing` is not continuing spans if a `AbstractInternalSpanDecorator` is being created. So for the following route

from("direct://foo")
				.log("hello")
				.to("direct://bar")
				.to("http://example.org");
		from("direct://bar")
				.log("hello")
				.to("direct://micrometer")
				.to("http://example.org");
		from("direct://micrometer")
				.setHeader(MicrometerConstants.HEADER_METRIC_NAME, constant("new.name"))
				.setHeader(MicrometerConstants.HEADER_METRIC_TAGS, constant(Tags.of("dynamic-key", "dynamic-value")))
				.to("micrometer:counter:name.not.used?tags=key=value")
				.to("direct://baz");
		from("direct://baz")
				.log("hello")
				.to("bean:com.example.cameldemo.MyBean")
				.to("exec:wc?args=--words /usr/share/dict/words")
				.process(exchange -> {
					// Use the Camel Exec String type converter to convert the ExecResult to String
					// In this case, the stdout is considered as output
					String wordCountOutput = exchange.getIn().getBody(String.class);
					// do something with the word count
					System.out.println(wordCountOutput);
				})
				.to("file:///tmp/camel-outputdir?flatten=true")
				.to("http://example.org");

you will get multiple traces since the `direct` components are not linked together (they are treated as a start of a new trace).

I think we agreed that for this route example, multiple routes are linked together but all in all they form a single trace. So if `org.apache.camel.tracing.Tracer.TracingEventNotifier#shouldExclude` would be changed from

private boolean shouldExclude(SpanDecorator sd, Exchange exchange, Endpoint endpoint) {
            return sd instanceof AbstractInternalSpanDecorator || !sd.newSpan()
                    || isExcluded(exchange, endpoint);
        }

to

private boolean shouldExclude(SpanDecorator sd, Exchange exchange, Endpoint endpoint) {
            return !sd.newSpan()
                    || isExcluded(exchange, endpoint);
        }

then the span parent-child relationship gets maintained the way it should

Issue Links

• is related to: CAMEL-19023 Add support for Micrometer Observation