How to create Context using traceId in Open Telemetry

I try to get all spans created in the following chain associated to the same trace context/traceId by context propagation:

service1 -> aws sqs queue -> service2

Auto. context propagation is not working with aws sqs and aws sdk v2 atm (https://github.com/open-telemetry/opentelemetry-java-instrumentation/issues/3684), even though the AwsTraceHeader is actually set in the sqs message, I have to take care for it explicitly by

service1: Writing traceId in sqs message user attribute traceId=Span.current().getSpanContext().getTraceId()
service2: Reading traceId from sqs message user attribute traceId and overwriting current span.traceId / essentially creating Context of service1

However, it is now unclear how to actually overwrite span.traceId in the span that service2 created which is confusing because for example with Golang it seems to be straightforward: How to create opentelemetry span from a string traceid

I see only getters e.g. Span.current().getSpanContext().getTraceId() but no setters or builder methods.

Update:

Even by creating a new span and making it current (not sure if this goes in the right direction) the tracer.spanBuilder does no offer setters for traceId AFAIU)

@Inject
io.opentelemetry.api.trace.Tracer tracer;

Span consumeMessageSpan = tracer.spanBuilder("consumeMessage").startSpan();

consumeMessage.makeCurrent();

Update 2

This snippet from otel official docs looks promising

To link spans from remote processes, it is sufficient to set the Remote Context as parent.

Span childRemoteParent = tracer.spanBuilder("Child").setParent(remoteContext).startSpan();

However, also no examples or ideas how to create remoteContext and setting traceId to the one extracted from the sqs message

Any hints how to do that?

Solution

I've done the following for a child JVM (that is running using the OTel auto-instrumentation agent):

    public static void main(String[] args) {
        Span span = createSpanLinkedToParent();
        try (Scope scope = span.makeCurrent()) {
            // do stuff
        } finally {
            span.end();
        }
    }

    private static Span createSpanLinkedToParent() {
        // Fetch the trace and span IDs from wherever you've stored them
        String traceIdHex = System.getProperty("otel.traceid");
        String spanIdHex = System.getProperty("otel.spanid");

        SpanContext remoteContext = SpanContext.createFromRemoteParent(
                traceIdHex,
                spanIdHex,
                TraceFlags.getSampled(),
                TraceState.getDefault());

        return GlobalOpenTelemetry.getTracer("")
                .spanBuilder("root span name")
                .setParent(Context.current().with(Span.wrap(remoteContext)))
                .startSpan();
    }

The next improvement I plan to make it to serialise the flags and state, perhaps using code here in Context Propagation https://opentelemetry.io/docs/instrumentation/java/manual/#context-propagation but the above works for now.