split up monolithic k8s yaml file

explode-manifest.sh

#!/usr/bin/env bash
# split a monolithic k8s manifest file into separate files.
set -euo pipefail
REMOVE_KEYS="chart:|release:|heritage:"

function usage {
  cat <<EOF
Usage: $(basename "$0") [output_dir] < input.yml

Explode a monolithic k8s manifest file into separate files during vendoring.
This aids in diff readability during updates. Output is further modified to
remove the keys chart/release/heritage (commonly found in rendered helm charts).

Example Usage:
  curl -sSL https://github.com/jetstack/cert-manager/releases/download/v0.8.0/cert-manager.yaml | $(basename "$0") test
EOF
  exit 1
}

if [[ -t 0 ]]; then
  usage
fi

# Get specified output directory.
OUTPUT_DIR=$PWD
if [[ $# -eq 1 ]]; then
  OUTPUT_DIR=$(realpath -m $1)
  mkdir -p $OUTPUT_DIR
  if [[ ! -e $OUTPUT_DIR ]]; then
    >&2 echo "Failed to create output directory ($OUTPUT_DIR)."
    exit 1
  fi
fi

# Create temporary directory to explode files for modification into.
TEMP_DIR=$(mktemp -d)
if [[ ! -e $TEMP_DIR ]]; then
  >&2 echo "Failed to create temp directory ($TEMP_DIR)."
  exit 1
fi
# Ensure we cleanup after ourselves.
trap "exit 1"           HUP INT PIPE QUIT TERM
trap 'rm -rf "$TEMP_DIR"' EXIT

cd $TEMP_DIR
sed '/^$/d' | csplit --suppress-matched -sz - '/^---$/' '{*}'
for file in xx*; do
  name=$(sed -n '/name: / {p;q}' $file | awk '{print tolower($2)}' | tr -d '\n' | tr -s -c [:alnum:][:blank:] -)
  kind=$(sed -n '/^kind: / {p;q}' $file | awk '{print tolower($2)}' | tr -d '\n' | tr -s -c [:alnum:][:blank:] -)
  if [[ "$kind" == *"list" ]]; then
    # list style resources contain many resources, hash the contents for name
    name=$(cat $file | md5sum | cut -d' ' -f1)
  fi
  if [[ "$kind" == "namespace" ]]; then
    printf "\nSkipping namespace resource, this belongs in overlays\n\n$(cat $file)\n\n"
  elif [[ -z "$name" ]]; then
    printf "\nSkipping potentially empty file, contents are: \n\n$(cat $file)\n\n"
  else
    destination="$OUTPUT_DIR/$kind-$name.yml"
    echo "Exploding to $destination."
    awk "!/$REMOVE_KEYS/" $file > $destination
  fi
done