Brave's SpanHandler can report natively in other formats which have different
constraints than Zipkin and often extensions to the data model.
This change ports all tests away from Zipkin's types so that it is more clear
what's actually recorded vs what's a side-effect of Zipkin conversion.
This removes `BlockingQueueSpanReporter` which was never released, also.
I had flakes on TraceAsyncIntegrationTests and it was hard to tell why
as there were so many problems with it. It used a normal list in async
setting, it unnecessarily created extra spans, it added a hook inside
the async method which if passed only told you it was in the middle of
an op, not the end of it. The method danced around making failure in
console almost impossible to decipher.
This took me a few hours to make just a normal test. Hopefully, the
others will keep passing as I can't afford time to redo all of them.
`SpanHandler` is the base type for the now deprecated `FinishedSpanHandler`.
Notable, it can not just handle things at the end of a recording, but also the
beginning.
For example, this permits set-once baggage without the HTTP abstraction:
```java
static final BaggageField EPOCH_SECONDS = BaggageField.create("epoch_seconds");
static final class RootOnlyBaggage extends SpanHandler {
@Override
public boolean begin(TraceContext context, MutableSpan span, @Nullable TraceContext parent) {
if (EPOCH_SECONDS.getValue(context) == null) { // only set at the first span
long epochSeconds = System.currentTimeMillis() / 1000;
EPOCH_SECONDS.updateValue(context, String.valueOf(epochSeconds));
}
return true;
}
@Override public boolean end(TraceContext context, MutableSpan span, Cause cause) {
Tags.BAGGAGE_FIELD.tag(EPOCH_SECONDS, context, span);
return true;
}
}
```
As the parent is available, it can also facilitate advanced tasks like counting
children, or summarizing entire local roots.
See https://github.com/openzipkin/brave/tree/master/brave/src/test/java/brave/features/handler
and https://github.com/openzipkin/brave/blob/master/brave/src/main/java/brave/handler/SpanHandler.java for more
`ExceptionLoggingFilter` logs "Uncaught exception thrown" to error level
when there is a synchronous exception not otherwise swallowed. This is a
cure worse than the disease. This disables it by default and the 3.x
should end the years of problems it caused.
Before, spring-cloud-sleuth-zipkin had to import `SamplerAutoConfiguration`
directly to unwind a sampler ordering problem caused by `TraceAutoConfiguration`
defining the default `Sampler` bean.
This fixes that by moving the default `Sampler` to where it belongs
(`SamplerAutoConfiguration`) and having `TraceAutoConfiguration` import
the sampling configuration directly as opposed to relying on auto-configuration
ordering. Finally it removes the mistake of setting `SamplerAutoConfiguration`
as auto-configuration in the first place.
The name `SamplerAutoConfiguration` was left alone because changing it would
interfere with 3rd party code that formerly imported it to correct this issue
in their non-zipkin setups.
Fixes#1618
