* plugin/forward: retry on cached tcp connection closed by peer

* fix linter warnings

* fixed unit test

* modify error message

This double checking for 1.9 and 1.10 is nice, but doubles the
travis test duration.

* plugin/forward: TCP conns can be closed

Only when we read and get a io.EOF we know the conn is closed (for TCP).
If this is the case Dial (again) and retry. Note that this new
connection can also be closed by the upstream, we may want to add a
DialForceNew or something to get a new TCP connection..

Simular to #1624, *but* this is by (TCP) design. We also don't have to
wait for a timeout which makes it easier to reason about.

* Move to forward.go

* doesnt need changing

Tagged an new release; has some fixes.

Return the client error if there was one instead of the generic
"no healthy upstream or error"

This registers the Collectors iff the metrics plugin has been loaded.
Safes a bunch of code in each and every plugin's setup code.

* plugin/metrics: set server address in context

Allow cross server block metrics to co-exist; for this we should label
each metric with the server label. Put this information in the context
and provide a helper function to get it out.

Abstracting with entirely away with difficult as the release client_go
(0.8.0) doesn't have the CurryWith functions yet. So current use is like
so:

define metric, with server label:

	RcodeCount = prometheus.NewCounterVec(prometheus.CounterOpts{
		Namespace: plugin.Namespace,
		Subsystem: "forward",
		Name:      "response_rcode_count_total",
		Help:      "Counter of requests made per upstream.",
	}, []string{"server", "rcode", "to"})

And report ith with the helper function metrics.WithServer:

	RcodeCount.WithLabelValues(metrics.WithServer(ctx), rc, p.addr).Add(1)

Drop the doTrue and doFalse and use a pointer to a bool to do a proper
tri-bool.

Check for trunacted in the lookup function as well and use the Match
function here as well.

My routers acts funny when it sees it non RD query; make this HC as
boring as possible

* plugin/{cache,forward,proxy}: don't allow responses that are bogus

Responses that are not matching what we've been querying for should be
dropped. They are converted into FormErrs by forward and proxy; as a 2nd
backstop cache will also not cache these.

* plug

* add explicit test

* request.Scrub: test for rl==size case

Make a test case for the new break statement in Scrub and also
account for the OPT record that may get re-added in SizeAndDo() -
otherwise we may break clients that expect this.

* Fix comment

Signed-off-by: Mario Kleinsasser <mario.kleinsasser@gmail.com>

Underscore these names.

Recent bind refactoring missed this:

    grpc://example.com.:1055
    example.com.:1053 on 127.0.0.1

now becomes

    grpc://example.com.:1055 on 127.0.0.1
    example.com.:1053 on 127.0.0.1

If you're using *bind* directive.

Remove startup and shutdown completely

This fix adds PTR record support for Route53 plugin

This fix fixes 1595
Signed-off-by: Yong Tang <yong.tang.github@outlook.com>

This PR documents the trick exposed in coredns/coredns#1357 about using wildcards to get all POD IPs from a service with ClusterIP (as used in 'endpoints')

While looking into route53 plugin I notice the test case
was incorrect and does not really test the reply. This
fix fixes the issue in the test.
Signed-off-by: Yong Tang <yong.tang.github@outlook.com>

These log print don't have any verbs, so just use plain Print

Jump through all the hoops to make this work.

* dockerfile: remove MAINTAINER

is a group effort and the field is deprecated anyways.
Fix comment to ref standard instead of impl. detail.

* link

Also add Also See Section.

Mechanical change; ran the above command.

* plugin/health: make reload work

Remove the once.Do from the startup, so we can re-bind the HTTP
listener. Also clarify the usage of health in multiple server blocks
(this is not the best approach - but there isn't a generic solution at
this point).

Manual tested as we lack testing infra, i.e kill -SIGUSR1 and some
CURLing of the health endpoint.

* Readme test fix

* update

* dont need this

* plugin/metrics: still need nil check for shutdown

the second prometheus statement will trigger: (on control-C)

[signal SIGSEGV: segmentation violation code=0x1 addr=0x28 pc=0x94f45a]

goroutine 25 [running]:
github.com/coredns/coredns/plugin/metrics.(*Metrics).OnShutdown(0xc420252000, 0x0, 0x0)
	/home/miek/g/src/github.com/coredns/coredns/plugin/metrics/metrics.go:107 +0x2a
github.com/coredns/coredns/plugin/metrics.(*Metrics).OnShutdown-fm(0x0, 0x0)
	/home/miek/g/src/github.com/coredns/coredns/plugin/metrics/setup.go:39 +0x2a
github.com/mholt/caddy.(*Instance).ShutdownCallbacks(0xc4202c81e0, 0x0, 0x0, 0x0)
	/home/miek/g/src/github.com/mholt/caddy/caddy.go:164 +0xb3
github.com/mholt/caddy.allShutdownCallbacks(0x1743935, 0x8, 0x14a1b40)
	/home/miek/g/src/github.com/mholt/caddy/sigtrap.go:95 +0x10d
github.com/mholt/caddy.executeShutdownCallbacks.func1()
	/home/miek/g/src/github.com/mholt/caddy/sigtrap.go:75 +0x8f
sync.(*Once).Do(0x2256b80, 0xc42036df88)
	/home/miek/upstream/go/src/sync/once.go:44 +0xbe
github.com/mholt/caddy.executeShutdownCallbacks(0x174033f, 0x6, 0x0)
	/home/miek/g/src/github.com/mholt/caddy/sigtrap.go:71 +0x73
github.com/mholt/caddy.trapSignalsCrossPlatform.func1.1()
	/home/miek/g/src/github.com/mholt/caddy/sigtrap.go:61 +0x36
created by github.com/mholt/caddy.trapSignalsCrossPlatform.func1
	/home/miek

* comments on why

Couldn't revert the original commit, just manually perform the needed
tweaks.