plugin/metrics: Switch to using promhttp instead of deprecated Handler (#1312)

prometheus.Handler is deprecated according to the godoc for the package so
instead we're using promhttp.

Additionally, we are exposing the Registry that metrics is using so other
plugins that are not inside of coredns can read the registry. Otherwise, if
we kept using the Default one, there's no way to access that from outside
of the coredns repo since it is vendored.

vendor/k8s.io/apimachinery/hack/godep-deps.sh

@@ -0,0 +1,66 @@
+#!/bin/bash
+
+# Copyright 2017 The Kubernetes Authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+
+# overall flow
+# 1. make a clean gopath
+# 2. godep restore based on k8s.io/kuberentes provided manifest
+# 3. go get anything unlisted.  This handles deps from k8s.io/*
+# 4. remove old vendoring data
+# 5. vendor packages we need
+# 6. remove anything vendored from k8s.io/* from vendor, but not manifest.
+#    This allows go get to work and still be able to flatten dependencies.
+# 6. copy new vendored packages and save them
+
+set -o errexit
+set -o nounset
+set -o pipefail
+
+goPath=$(mktemp -d "${TMPDIR:-/tmp/}$(basename 0).XXXXXXXXXXXX")
+echo ${goPath}
+
+export GOPATH=${goPath}
+
+mkdir -p ${goPath}/src/k8s.io/apimachinery
+cp -R . ${goPath}/src/k8s.io/apimachinery
+
+pushd ${goPath}/src/k8s.io/apimachinery
+rm -rf vendor || true
+
+# restore what we have in our new manifest that we've sync
+godep restore
+
+# the manifest doesn't include any levels of k8s.io dependencies so load them using the go get
+# assume you sync all the repos at the same time, the leves you get will be correct
+go get -d ./... || true
+
+# save the new levels of dependencies
+rm -rf vendor || true
+rm -rf Godeps || true
+godep save ./...
+popd
+
+# remove the vendor dir we have and move the one we just made
+rm -rf vendor || true
+rm -rf Godeps || true
+git rm -rf vendor || true
+git rm -rf Godeps || true
+mv ${goPath}/src/k8s.io/apimachinery/vendor .
+mv ${goPath}/src/k8s.io/apimachinery/Godeps .
+git add vendor
+git add Godeps
+git commit -m "sync: resync vendor folder"
+

vendor/k8s.io/apimachinery/hack/sync-from-kubernetes.sh

@@ -0,0 +1,65 @@
+#!/bin/bash
+
+# Copyright 2017 The Kubernetes Authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+
+# overall flow
+# 1. fetch the current level of k8s.io/kubernetes
+# 2. check out the k8s.io/kubernetes HEAD into a separate branch
+# 3. rewrite the history on that branch to *only* include staging/src/k8s.io/apimachinery
+# 4. locate all commits between the last time we sync'ed and now
+# 5. switch back to the starting branch
+# 6. for each commit, cherry-pick it (which will keep authorship) into current branch
+# 7. update metadata files indicating which commits we've sync'ed to
+
+set -e
+
+ROOT=$(dirname "${BASH_SOURCE}")/..
+dir=$(mktemp -d "${TMPDIR:-/tmp/}$(basename 0).XXXXXXXXXXXX")
+
+git remote add upstream-kube git@github.com:kubernetes/kubernetes.git  || true
+git fetch upstream-kube
+
+currBranch=$(git rev-parse --abbrev-ref HEAD)
+previousKubeSHA=$(cat kubernetes-sha)
+previousBranchSHA=$(cat filter-branch-sha)
+
+git branch -D kube-sync || true
+git checkout upstream-kube/master -b kube-sync
+git reset --hard upstream-kube/master
+newKubeSHA=$(git log --oneline --format='%H' kube-sync -1)
+
+# this command rewrite git history to *only* include staging/src/k8s.io/apimachinery
+git filter-branch -f --subdirectory-filter staging/src/k8s.io/apimachinery HEAD
+
+newBranchSHA=$(git log --oneline --format='%H' kube-sync -1)
+git log --no-merges --format='%H' --reverse ${previousBranchSHA}..HEAD > ${dir}/commits
+
+git checkout ${currBranch}
+
+while read commitSHA; do
+	echo "working ${commitSHA}"
+	git cherry-pick ${commitSHA}
+done <${dir}/commits
+
+# update the vendored godeps
+${ROOT}/hack/godep-deps.sh
+
+# track the k8s.io/kubernetes commit SHA so we can always determine which level of kube this repo matches
+# track the filtered branch commit SHA so that we can determine which commits need to be picked
+echo ${newKubeSHA} > kubernetes-sha
+echo ${newBranchSHA} > filter-branch-sha
+git commit -m "sync(k8s.io/kubernetes): ${newKubeSHA}" -- kubernetes-sha filter-branch-sha
+