* tests: CoreDNSServerAndPorts
Copy from kubernetes.go and renamed to fit the style, adapted almost
all callers.
This is a mechanicl change, no testdata was changed.
* typos
Singleinflight interferes with the health checking of upstream. If an
upstream would fail, singleinflight would mirror that error to to other
proxy *iff* multple identical queries would be inflight. This would lead
to marking *all* upstreams as bad, essentially collapsing multiple
upstreams into a SPOF. Clearly not what we want.
Singleinflight does have some nice properties, but I've opted to rip it
out entirely. Caching should almost (but not quite) as good.
Added a test case in test that uses 3 CoreDNS instances to reflect the
setup from #715.
Found another bug as well, where (when the policy would be nil), we
would always Spray even though we've found a healthy host.
By defining and using an proxy.Exchanger interface we make the proxy
more generic and we can then fold back httproxy into proxy.
This overrides #463 and #473 and should make futures extensions rather
trivial
* Add docs that talk about `protocol` and how to set it.
* middleware/proxy: rename New to NewLookup
It's used as a Lookup mechanism not as a completely new proxy,
reflect that in the name.
* Set maxfails to 3 by default when looking up names.
Most of the changes have been copied
from https://github.com/johnbelamaric/coredns/pull/1/files
Add deadline to break the connection. We use the default of 5 seconds.
After this the backend is marked unhealthy and not used for some time.
Fixes#467
