helm-dependencies.sh

#!/usr/bin/env bash
set -euo pipefail

# helm-dependencies.sh
#
# SUMMARY
#
#   Update Helm chart dependencies in the proper order to propagate
#   the changes.
#
#   This script implements our custom compatible dependency update mechanism,
#   rather than relying on the official `helm dependency update`.
#   We'd be happy to, however, the official mechanism doesn't produce
#   reproducible results.
#   See https://github.com/helm/helm/issues/8850

cd "$(dirname "${BASH_SOURCE[0]}")/.."

# Read the shared scripting config.
source "distribution/helm/scripting-config.sh"

list-chart-dependencies() {
  local CHART="$1"
  helm dependency list "$CHART" | tail -n +2 | sed '/^$/d' | awk '{ gsub("file://", "", $3); print $1, $3 }'
}

symlink_posix() {
  local LINK_TARGET="$1"
  local LINK_NAME="$2"
  ln -sfn -T "$LINK_TARGET" "$LINK_NAME"
}

symlink_windows() {
  local LINK_TARGET="$1"
  local LINK_NAME="$2"
  cmd >/dev/null <<EOF
mklink /D "${LINK_NAME//\//\\}" "${LINK_TARGET//\//\\}"
EOF
}

list() {
  for CHART in "${DEPENDENCY_UPDATE_ORDER[@]}"; do
    echo "=> $CHART"
    list-chart-dependencies "distribution/helm/$CHART"
  done
}

update() {
  if [[ "${OS:-}" == "Windows_NT" ]]; then
    SYMLINK_COMMAND="symlink_windows"
  else
    SYMLINK_COMMAND="symlink_posix"
  fi

  for CHART in "${DEPENDENCY_UPDATE_ORDER[@]}"; do
    echo "=> $CHART"

    CHART_PATH="distribution/helm/$CHART"
    CHART_VENDORED_DEPENDENCIES_PATH="$CHART_PATH/charts"

    rm -rf "$CHART_VENDORED_DEPENDENCIES_PATH"
    mkdir -p "$CHART_VENDORED_DEPENDENCIES_PATH"

    while IFS= read -r DEPENDENCY_PAIR; do
      read -ra KV <<<"$DEPENDENCY_PAIR"
      DEPENDENCY_NAME="${KV[0]}"
      DEPENDENCY_PATH="${KV[1]}"

      LINK_TARGET="../$DEPENDENCY_PATH"
      LINK_NAME="$CHART_VENDORED_DEPENDENCIES_PATH/$DEPENDENCY_NAME"

      echo "Symlinking \"$DEPENDENCY_NAME\" with name \"$LINK_NAME\" and target \"$LINK_TARGET\"..."
      "$SYMLINK_COMMAND" "$LINK_TARGET" "$LINK_NAME"
    done < <(list-chart-dependencies "$CHART_PATH")
  done
}

validate() {
  for CHART in "${DEPENDENCY_UPDATE_ORDER[@]}"; do
    echo "=> $CHART"

    CHART_PATH="distribution/helm/$CHART"
    CHART_VENDORED_DEPENDENCIES_PATH="$CHART_PATH/charts"

    while IFS= read -r DEPENDENCY_PAIR; do
      read -ra KV <<<"$DEPENDENCY_PAIR"
      DEPENDENCY_NAME="${KV[0]}"
      DEPENDENCY_PATH="${KV[1]}"

      VENDORED_PATH="$CHART_PATH/$DEPENDENCY_PATH"
      UPSTREAM_PATH="$CHART_VENDORED_DEPENDENCIES_PATH/$DEPENDENCY_NAME"

      echo "Validating \"$DEPENDENCY_NAME\" at \"$VENDORED_PATH\" against \"$UPSTREAM_PATH\"..."
      diff -qr "$VENDORED_PATH" "$UPSTREAM_PATH"
    done < <(list-chart-dependencies "$CHART_PATH")
  done
}

usage() {
  cat >&2 <<-EOF
Usage: $0 MODE

Modes:
  update   - update Helm chart dependencies and vendor them to the respective
             charts/ dir of each chart.
  validate - check that vendored Helm chart dependencies are up-to-date with
             with their upstream counterparts.
  list     - list the dependencies for each Helm chart.
EOF
  exit 1
}

MODE="${1:-}"
case "$MODE" in
list | update | validate)
  "$MODE"
  ;;
*)
  usage
  ;;
esac