* feat(aws): support multiple hosted zones and automatic lookup

* chore: run gofmt with the simplified command

* fix(aws): add missing method from google provider

* fix: remove superflous parameter from google provider

* feat: make domain configurable via flag

* fix(aws): remove unused constant

* fix(aws): don't log actions that were filtered out

* feat(aws): detect best possible zone to put dns entries in

* fix(aws): log error instead of failing if a change batch fails

* chore: update changelog with support for multiple zones

* feat(plan): allow plans to be parameterized via policies

* fix(controller): set a policy in the controller tests

* chore: allow go tip to fail

* chore: update changelog to include policies

* fix(plan): store a pointer to changes

* fix(controller): don't get address of a pointer

* kickoff txt registry

* fix inmemory dns provider to include recordtype info for validation

* Merge master

* fix ununsed variable in inmemory provider

* add tests for records

* add test for no prefix name formatter

* implement apply changes with tests

* add flag to enable txt registry

* add txt registry to main

* improve sort testing

* filter out non-owned records

* NewEndpoint(...) requires record type

* use newendpoint in aws_test, fix tests

* change suitable type implementation

* fix the test for compatibility component

* change inmemory provider to include recordtype and use suitable type

* fix comments, CNAME should target hostname

* name mapper do not use pointer on struct

* txt prefix - just concatenate, remove spew, fix txt record label

* allow TXT records as result from dns provider

* add changelog

* fix tests

* TXT records need to be enclosed in double quotes

* define registry interface

* init in-memory registry

* remove ununsed variable, added comments

* add inmemory registry tests

* introduce DNSRecord struct

* use noop registry

* remove zone from registry fields

* replace provider with registry in controller

* move noop registry interface check to test

* remove ownerid from noop registry

* fix: remove dangling empty line

* return provider records directly with noop

* adjust according to pr review

* fix noop tests

* feat: expose basic go metrics via prometheus

* chore: vendor dependencies

* feat(metrics): combine healthz and metrics into single endpoint

* ref(metrics): rename metrics port to address

* docs(metrics): update changelog to include metrics feature

* ref(metrics): consistently rename port to address

* fix(dnsprovider): do not always initialize each DNS provider

* fix(dnsprovider): fix unnecessary error return value

* ref(dnsprovider): drop the store and use a simple switch for lookup

* ref(source): use constructor methods to create sources

* fix: import and use missing package

* fix(source): fix merge conflict with master branch

* feat(google): add ability to apply changes generated from a plan

* feat(controller): first implementation of controller

* feat: allow to configure in-cluster and kubeconfig

* fix(controller): call RunOnce at the right time and in a loop

* feat(google): add dryRun attribute to Google DNS provider

* fix: use hosted zone id instead of DNS name

* fix(google): stupidly filter by A records for now

* feat: allow specifying the google project and zone

* feat: provide a dry-run flag which defaults to false

* chore: vendor new dependencies

* fix(config): fix failing tests for config object

* ref(controller): return plain value of ApplyChanges

* ref: simplify how to get a valid kubernetes client

Types that we want to work using apimachinery typically go into
pkg/apis/X, and the validation goes into pkg/apis/X/validation.  We then
add versions into e.g. pkg/apis/X/v1alpha1, but this feels premature at
the moment.

Changing this later is annoyingly difficult, especially in terms of
validation and dependencies.

We will want the apimachinery, so that we can configure from a
configuration file that is versioned.  Hopefully dns-controller won't
end up so complicated that we will require it, but I think there is also
value in following the "standard" patterns for controllers that are
emerging from e.g. ingress.

For a fairly simple example of an API, please consult
https://github.com/kubernetes/kubernetes/tree/master/pkg/apis/certificates