Picking a span name is not a trivial task. Span name should depict an operation name. The name should be low cardinality (e.g. not include identifiers).
Since there is a lot of instrumentation going on some of the span names will be artificial like:
controller-method-name when received by a Controller with a method name conrollerMethodNameasync for asynchronous operations done via wrapped Callable and Runnable.@Scheduled annotated methods will return the simple name of the class.Fortunately, for the asynchronous processing you can provide explicit naming.
You can name the span explicitly via the @SpanName annotation.
@SpanName("calculateTax") class TaxCountingRunnable implements Runnable { @Override public void run() { // perform logic } }
In this case, when processed in the following manner:
Runnable runnable = new TraceRunnable(tracer, spanNamer, new TaxCountingRunnable()); Future<?> future = executorService.submit(runnable); // ... some additional logic ... future.get();
The span will be named calculateTax.
It’s pretty rare to create separate classes for Runnable or Callable. Typically one creates an anonymous
instance of those classes. You can’t annotate such classes thus to override that, if there is no @SpanName annotation present,
we’re checking if the class has a custom implementation of the toString() method.
So executing such code:
Runnable runnable = new TraceRunnable(tracer, spanNamer, new Runnable() { @Override public void run() { // perform logic } @Override public String toString() { return "calculateTax"; } }); Future<?> future = executorService.submit(runnable); // ... some additional logic ... future.get();
will lead in creating a span named calculateTax.