* WIP: add k8s grouper
- This shares a great deal of behaviour with allGrouper. Once it's
tested, refactor that to share as much as possible
- Glide hell. Checked in the yaml and lock files but a glide i -v
will be required to bring vendor/ up-to-date. Will address once this
is ready.
* Update README. Make the watch tracking work.
(To follow: add the junk that was pulled in via the glide update.)
* Vendor updates.
* go fmt
* Use the allGrouper with a k8s-backed DBStore instead.
This is much tidier :-)
* Fix up go vet
* fn: fnlb: enhancements and new grouper tests
*) added healthy threshold (default: 1)
*) grouper is now using configured hcEndpoint for version checks
*) grouper now logs when servers switch between healthy/unhealthy status
*) moved DB code out of grouper
*) run health check immediately at start (don't wait until hcInterval)
*) optional shutdown timeout (default: 0) & mgmt port (default: 8081)
*) hot path List() in grouper now uses atomic ptr Load
*) consistent router: moved closure to a new function
*) bugfix: version parsing from fn servers should not panic fnlb
*) bugfix: servers removed from DB, stayed in healthy list
*) bugfix: if DB is down, health checker stopped monitoring
*) basic new tests for grouper (add/rm/unhealthy/healthy) server
