* Make CoreDNS a server type plugin for Caddy
Remove code we don't need and port all middleware over. Fix all tests
and rework the documentation.
Also make `go generate` build a caddy binary which we then copy into
our directory. This means `go build`-builds remain working as-is.
And new etc instances in each etcd test for better isolation.
Fix more tests and rework test.Server with the newer support Caddy offers.
Fix Makefile to support new mode of operation.
Changes large parts of proxy lookup mechanism.
The duplicate zone checking erroneous added a nameserver for each
zone we are auth. for, creating to many backend hosts. So even when a
host was determined do be Down() we still got an (identical) new one
from the list.
The Down() and failure checking for upstream hosts had data race in the
uh.Fails check - we now use atomic.LoadInt32 for that.
Use and debug the test/server.go test servers implementation in the
TestStubLookup test to prevent going out to the internet.
Also delete the stub cycle test. That test was wrong and did not test
what it needed to be testing. Deleted for now.
* middleware/proxy: add spray keyword
When spray is used, the proxy will, when all backend are down, spray to
each target. When not used, default to the old defaults: max 1 failure
and no spray. These defaults are also used when forwarding queries to
another CoreDNS instance.
Update the README with the new keyword.
* typos
* Make MaxFail = 1 again
* more reversals
