How to append Strackdriver trace with custom spans using Opencencsus library?

Question

I'm setting up a Standard, Java, AppEngine Service and I need to trace custom location in the code. I have followed the tutorial provided by Google: https://cloud.google.com/trace/docs/setup/java to setup the tracing, however the issue, is that that approach creates a new trace rather than appending new spans to the trace started by Google.

To append new spans to an existing trace I have tried extracting the traceId and rootSpanId from X-Cloud-Trace-Context header, and using spanBuilderWithRemoteParent method to create child spans.

However, the problem is that, SpanId.fromLowerBase16 expects a 16 byte ID, where as the rootSpanId is 19 bytes long. Thus my code throws a java.lang.IllegalArgumentException: Invalid size: expected 16, got 19 exception.

Code example:

List<String> traceHeaders = headers.get("X-Cloud-Trace-Context");
String traceID = "";
String rootSpanId = "";
if (traceHeaders.size() > 0) {
    traceID = traceHeaders.get(0).split("/")[0];
    rootSpanId = traceHeaders.get(0).split("/")[1].split(";")[0];
}

Span sp1 =
    tracer
        .spanBuilderWithRemoteParent(
            "fetch-data",
            SpanContext.create(
                TraceId.fromLowerBase16(traceID),
                SpanId.fromLowerBase16(rootSpanId), <- exception thrown here
                tracer.getCurrentSpan().getContext().getTraceOptions()))
        .setSampler(Samplers.alwaysSample())
        .startSpan();

Thus, is there a way to append customs spans to an existing Stackdriver trace using Opencensus library, or are we limited to using Stackdriver Trace API?

How to append Strackdriver trace with custom spans using Opencencsus library?

0 Answers0