feat: add prune repo script (cncf#2866)

adds script to prune repo to tidy up repo size

Signed-off-by: Caleb Woodbine <calebwoodbine.public@gmail.com>

hack/prune-repo.sh

@@ -0,0 +1,49 @@
+#!/bin/bash
+
+# Copyright 2023 CNCF.
+#
+# 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.
+
+set -o errexit
+set -o nounset
+set -o pipefail
+
+cd "$(dirname "$(realpath "$0")")"
+cd "$(git rev-parse --show-toplevel)"
+
+UNWANTED_FILE_TYPES=(zip)
+
+echo "notice: gathering facts..."
+OLDEST_UNSUPPORTED='v1.7'
+LAST_KEPT_SUBMISSIONS="5"
+KUBERNETES_STABLE_VERSION="$(curl -sSL https://storage.googleapis.com/kubernetes-release/release/stable.txt)"
+KV_MA="$(echo "${KUBERNETES_STABLE_VERSION}" | grep -Eo '^v[1]')"
+KV_MI="$(echo "${KUBERNETES_STABLE_VERSION}" | sed 's/v[1].\(.*\)\..*/\1/g')"
+OLDEST_UNSUPPORTED_MI="$(echo "$OLDEST_UNSUPPORTED" | grep -Eo '[0-9]{1,2}$')"
+LAST_SUPPORTED_MI="$(echo $((KV_MI-=LAST_KEPT_SUBMISSIONS)))"
+cat <<EOF
+- oldest tracked release            : $OLDEST_UNSUPPORTED
+- latest stable release             : $KV_MA.$KV_MI
+- keeping the last so-many releases : $LAST_KEPT_SUBMISSIONS
+- pruning versions up until         : $KV_MA.$LAST_SUPPORTED_MI
+- pruning file-types                : (${UNWANTED_FILE_TYPES[@]})
+EOF
+
+echo -e "\nnotice: removing unwanted files\n"
+echo "${UNWANTED_FILE_TYPES[@]/#/$'\n'}" | xargs -I{} git filter-repo --force --path-glob '*.{}' --invert-paths
+
+echo -e "\nnotice: removing unsupported releases\n"
+seq "$OLDEST_UNSUPPORTED_MI" "$LAST_SUPPORTED_MI" | sed "s/^/$KV_MA./g" | xargs -I{} git filter-repo --force --path {} --invert-paths
+
+echo -e "\nnotice: complete\n"
+echo -e "TODO: git push -f origin $(git rev-parse --abbrev-ref HEAD)"