audit: add create-or-update-audit-pr.sh

This is mostly a straight copy-paste of the bash-script embedded in the
ci-k8sio-audit job defined in:

- repo: https://github.com/kubernetes/test-infra
- sha: 624c7344bdb56bd25e119a8b1ccc284939861938
- file: config/jobs/kubernetes/wg-k8s-infra/trusted/wg-k8s-infra-trusted.yaml

Added boilerplate header, comments up top, and put line breaks in
between each block of code beginning with an echo statement

audit/create-or-update-audit-pr.sh

@@ -0,0 +1,80 @@
+#!/usr/bin/env bash
+
+# Copyright 2021 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.
+
+# Run the audit script and create or update a PR containing any changes
+
+# NOTE: This is intended to run on k8s-infra-prow-build-trusted as
+#       [email protected]
+
+# TODO: Running locally is a work in progress, there are assumptions
+#       made about the environment in which this runs:
+#       - must have certain env vars present
+#       - must have kubernetes/test-infra in a certain location
+#       - must be able to build kubernetes/test-infra
+#       - must have gcloud already authenticated as someone who has the
+#         custom org role "audit.viewer"
+
+set -o errexit
+set -o nounset
+set -o pipefail
+
+GH_USER=cncf-ci
+GH_NAME="CNCF CI Bot"
+GH_EMAIL="[email protected]"
+FORK_GH_REPO=k8s.io
+FORK_GH_BRANCH=autoaudit-${PROW_INSTANCE_NAME:-prow}
+
+echo "Ensure git configured" >&2
+git config user.name "${GH_NAME}"
+git config user.email "${GH_EMAIL}"
+
+echo "Ensure gcloud creds are working" >&2
+gcloud config list
+
+echo "Running Audit Script to dump GCP configuration to yaml" >&2
+pushd ./audit
+bash ./audit-gcp.sh
+popd
+
+echo "Determining whether there are changes to push" >&2
+git add --all audit
+git commit -m "audit: update as of $(date +%Y-%m-%d)"
+git remote add fork "https://github.com/${GH_USER}/${FORK_GH_BRANCH}"
+if git fetch fork "${FORK_GH_BRANCH}"; then
+    if git diff --quiet HEAD "fork/${FORK_GH_BRANCH}" -- audit; then
+    echo "No new changes to push, exiting early..." >&2
+    exit
+    fi
+fi
+
+echo "Generating pr-creator binary from k/test-infra/robots" >&2
+pushd ../../kubernetes/test-infra
+go build -o /workspace/pr-creator robots/pr-creator/main.go
+popd
+
+echo "Pushing commit to github.com/${GH_USER}/${FORK_GH_REPO}..." >&2
+GH_TOKEN=$(cat /etc/github-token/token)
+git push -f "https://${GH_USER}:${GH_TOKEN}@github.com/${GH_USER}/${FORK_GH_REPO}" "HEAD:${FORK_GH_BRANCH}" 2>/dev/null
+
+echo "Creating or updating PR to merge ${GH_USER}:${FORK_GH_BRANCH} into kubernetes:main..." >&2
+/workspace/pr-creator \
+    --github-token-path=/etc/github-token/token \
+    --org=kubernetes --repo=k8s.io --branch=main \
+    --source="${GH_USER}:${FORK_GH_BRANCH}" \
+    --head-branch="${FORK_GH_BRANCH}" \
+    --title="audit: update as of $(date +%Y-%m-%d)" \
+    --body="Audit Updates wg-k8s-infra" \
+    --confirm