Automatically submitted.

* Provide example to utilize k8s_external plugin

The example provides a specific use case of k8s_external and may help others to grasp `k8s_external`'s capabilities.

* Update plugin/k8s_external/README.md
Co-Authored-By: Chris O'Haver <cohaver@infoblox.com>

* Update plugin/k8s_external/README.md
Co-Authored-By: Chris O'Haver <cohaver@infoblox.com>

Fighting with hugo - dates can't be quoted.
Signed-off-by: Miek Gieben <miek@miek.nl>

Signed-off-by: Miek Gieben <miek@miek.nl>

* add metrics for reload
* documented release process better
* run: Makefile.doc all to push reload doc to man-pages
Signed-off-by: Miek Gieben <miek@miek.nl>

* Issue 2920
- Add failed reload counter metrics

* typo fix

* Requested Changes

* Run gofmt -s and golint on the codebase

Run golint and fix everythign it flagged (except the context arg
ordering), mostly edits in the rewrite plugin.
Signed-off-by: Miek Gieben <miek@miek.nl>

* ... and ofcourse the test as well
Signed-off-by: Miek Gieben <miek@miek.nl>

* Update zipkin, etcd, klog and aws

This fix updates:
- github.com/openzipkin/zipkin-go-opentracing
- k8s.io/klog
- github.com/coreos/etcd
- github.com/aws/aws-sdk-go

This fix fixes #2906
This fix fixes #2907
This fix fixes #2908
This fix fixes #2909
Signed-off-by: Yong Tang <yong.tang.github@outlook.com>

* Also updates opentracing
Signed-off-by: Yong Tang <yong.tang.github@outlook.com>

* Add 1.5.1 release notes

Prepare for imminent release.
Also list PRs merged in a new section to provide more detail.
Signed-off-by: Miek Gieben <miek@miek.nl>

* Updates after review
Signed-off-by: Miek Gieben <miek@miek.nl>

mechanical change: create the manual pages.
Signed-off-by: Miek Gieben <miek@miek.nl>

This fix updates:
- github.com/miekg/dns from 1.1.12 to 1.1.14
- google.golang.org/grpc from 1.21.0 to 1.21.1
- github.com/aws/aws-sdk-go from 1.19.41 to 1.20.3
- github.com/prometheus/common from 0.4.1 to 0.6.0
- gopkg.in/DataDog/dd-trace-go.v1 from 1.14.0 to 1.15.0

This fix fixes #2899
This fix fixes #2900
This fix fixes #2901
This fix fixes #2902
This fix fixes #2903
Signed-off-by: Yong Tang <yong.tang.github@outlook.com>

* plugin/file: document using an explicit origin

See #2880
Signed-off-by: Miek Gieben <miek@miek.nl>

* Code review comments
Signed-off-by: Miek Gieben <miek@miek.nl>

* add circleci

* make ci work

* use existing script for setup

* add sep step for getting CI repo

Signed-off-by: Xiao An <hac@zju.edu.cn>

Signed-off-by: Xiao An <hac@zju.edu.cn>

* plugin/cache: remove item.Autoritative

Confuses clients if not set; remove it.
Signed-off-by: Miek Gieben <miek@miek.nl>

* Add extra comments on why we do this
Signed-off-by: Miek Gieben <miek@miek.nl>

This fix is a follow up on comment https://github.com/coredns/coredns/pull/2868#discussion_r291609761Signed-off-by: Yong Tang <yong.tang.github@outlook.com>

While running make encountered the following error:
```
$ docker run -i -t --rm -v $PWD:/v --net=host -w /v golang:1.12 make
...
...
** presubmit/test-lowercase
plugin/kubernetes/metadata_test.go:			t.Errorf("case %d expected metadata %v and got %v", i, tc.Md, md)
** presubmit/test-lowercase: please start with an upper case letter when using t.Error*()
Makefile:62: recipe for target 'presubmit' failed
make: *** [presubmit] Error 1
```
Signed-off-by: Yong Tang <yong.tang.github@outlook.com>

- Fixes #2862

* Publish metadata from kubernetes plugin

* stickler fix

* Add a couple tests

* Add metadata section to README

* Update plugin/kubernetes/README.md
Co-Authored-By: Chris O'Haver <cohaver@infoblox.com>

* Address nit

Add OnRestartFailed to the ready plugin and some various cleanups.

Document slightly better how things are supposed to work with multiple
`ready`'s in the multiple Server Blocks.

All manually tested with this Corefile:
~~~
. {
    log
    ready
}

example.org {
    log
    chaos
    ready
}
~~~
And then `kill -SIGUSR1` and curling the ready endpoint. This works
well, the FailedReload is triggered by adding a syntax error in the
Corefile.

See #2659
Signed-off-by: Miek Gieben <miek@miek.nl>

This reverts commit a657e1f6.

otherwise the connection and associated socket stay in the CLOSE_WAIT
state unless/until golang runtime performs GC.

This fix updates several direct dependencies (grpc, aws, protobuf) in go mod,
and removed duplicates with `go mod tidy`

Note: tracing related dependencies are not touched, as
DataDog/tracing dependencies still give trouble.
Signed-off-by: Yong Tang <yong.tang.github@outlook.com>

Don't add pods to our internal cache that are being deleted. This saves
a field in the struct as well.

Add (extra) comments about adding fields to the
object/{Pod,Service,Endpoint} structs.
Signed-off-by: Miek Gieben <miek@miek.nl>

General syntactic cleanup.

* make sure client CA and auth type are set if CA is explicitly specified.

added some simple tests to confirm the effect.

* test certificates (forgot to add them in the previous commit)

* made client auth policy configurable with new client_auth option.

README has been updated accordingly.

* fix editorial in README

* client-go 11.0.0

* Core moved to CoreV1

* Fix for #2842, instead of returning the first Pod, return the one which is Running

* a more memory efficient version of the fix, string -> bool

* fix with no extra fields in struct, return nil at Pod conversion if Pod is not Running

* let Kuberneretes filter for Running Pods using FieldSelector

* filter for Pods that are Running and Pending (implicit)

* Add server instance to the context in ServerTLS and ServerHTTPS

The problem with the current code is that there's no way to get the server instance inside a plugin.
Because of that "metrics" plugin sets empty "server" label for requests served over TLS or HTTPS.

* use s.Server instead of s

* Added server to the context of grpc requests

This fix:
1. Update dns to v1.1.12
2. Redirect dns v1.1.3 in caddy to v1.1.12 so that there is only one version of dns.
Signed-off-by: Yong Tang <yong.tang.github@outlook.com>

Update shebangs for environmentally finding Bash -- Compatibility update to provide support for platforms that do not ship Bash in their /bin (#2841)

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