This updates to latest zipkin, adding a flag to gzip spans before
posting them. Note this is set to false by default as it requires servers
to also be latest. We can flip the default once we can assume that.
Ex. `spring.zipkin.compression.enabled = true`
Changes following review
- Reusing CounterService to automatically profit from Dropwizard if present
- NoOp is the default impl for SpanReporterService
- SpanReporterService has configurable metric names (it's enough to change the
name to 'meter.a.b.c' to profit from Dropwizard's meters)
Fixes gh-99
- Changed Random instantiation to a shared Random
- Changed the name of the converter
- Changed generator into random
- Span id is now non-nullable.
- it gets generated in the http filter if it's not there
- it's generated in the spring-integration channels if it wasn't set
It's not really necessary to use rabbit, but the existing tests
weren't really using the stream components at all because
zipkin spans were being collected by spring-cloud-sleuth-zipkin.
Recent versions of zipkin and brave operate with http instead of scribe.
This changes the implementation accordingly, as well adds a sampler to
the POST endpoint.
A notable impact is that we no longer require a collector process, as
the zipkin server's POST endpoint is a collector.
