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
Previously, sleuth logged more data than necessary. This led to issues
including spans approaching megabytes each. This pares down default keys
to a minimal set, but allows users to opt-into logging more by extending
`TraceFilter`.
- 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
Instrumentation should be able to get by with only 2
interfaces: TraceManager and TraceAccessor (the former is
not needed if you aren't starting a new Span). No explicit
access to thread locals or manipulation of thread context
is required (except locally where necessary).
A Span is enclosed by a Trace (actually a view of the complete
Trace that would be constructed remotely).
