helm2tf.sh

#!/bin/sh

DEFAULT_CHART="${1:-grafana/loki-stack}"
REPO_NAME="${2:-grafana}"
REPO_URL="${3:-https://grafana.github.io/helm-charts}"

helm repo add "${REPO_NAME}" "${REPO_URL}"
helm search repo "${REPO_NAME}"
read -p "Chart? [${DEFAULT_CHART}]: " CHART
[ -z "${CHART}" ] && CHART="${DEFAULT_CHART}"
if [ 0 -eq $(helm search repo "${REPO_NAME}" | grep -c "^${CHART}\s") ]; then
    >&2 echo "ERROR chart not found: ${CHART}"
    exit 1
fi

REPO_CHART=$(echo ${CHART} | sed -r 's#^'${REPO_NAME}'/##')
CHART_YAML="yaml/${CHART}.yaml"
CHART_YAML_DIR="$(dirname ${CHART_YAML})"
CHART_TF="tf/${CHART}.tf"
CHART_TF_DIR="$(dirname ${CHART_TF})"

# if [ -z "$(command -v dredger)" ]; then
#     [ -d "$(dirname $0)/dredger" ] || (git clone https://github.com/synchronoss/dredger.git && cd dredger && make dredger)
#     PATH="$(dirname $0)/dredger:$PATH"
# fi

# If tool k2tf not present ...
if [ -z "$(command -v k2tf)" ]; then
  # ... build it from source and add directory to PATH ...
  [ -d "$(dirname $0)/k2tf" ] || (git clone https://github.com/sl1pm4t/k2tf.git && cd k2tf && make build)
  PATH="$(dirname $0)/k2tf:$PATH"
fi

# YAMLs ...
rm -rf "${CHART_YAML_DIR}" \
&& mkdir -p "${CHART_YAML_DIR}" \
&& helm --debug template '${var.repo_chart}' --namespace '${var.namespace}' --repo "${REPO_URL}" "${REPO_CHART}" > "${CHART_YAML}"
# ... proceed even if helm failed ...
( \
  cd "${CHART_YAML_DIR}" \
  && csplit --quiet --prefix='split-' --suffix-format='%03d.yaml' -z --suppress-matched "$(basename ${CHART_YAML})" /---/ '{*}' \
  && rm "$(basename ${CHART_YAML})"; \
) \
&& grep -HR '# Source:' "${CHART_YAML_DIR}" \
 | sed -r 's#^.*/(.*).yaml:[^:]*: (.*).yaml$#\1:\2#g' > "${CHART_YAML_DIR}/splits.txt" \
&& awk -F: '{printf "(cd '${CHART_YAML_DIR}' && mv %s.yaml %s.yaml;)\n", $1, gensub("/", "-", "g", $2)}' "${CHART_YAML_DIR}/splits.txt" \
 | sh \
&& rm "${CHART_YAML_DIR}/splits.txt"

# fix unquoted strings in array (role.yaml I'm looking at you) ...
for F in $(fgrep -lR '[${' "${CHART_YAML_DIR}"); do
  sed -ri'' 's#\[(\s*\$\{[^}]*)}([^]]*)#['\''\1}\2'\''#g' $F
done

## TFs ...
rm -rf "${CHART_TF_DIR}" \
&& mkdir -p "${CHART_TF_DIR}" \
&& find "${CHART_YAML_DIR}" -type f -name '*.yaml' -exec basename {} \; \
 | xargs -I{} sh -c 'echo k2tf --overwrite-existing -f "'${CHART_YAML_DIR}'"/{} -o "'${CHART_TF_DIR}'/$(echo {}|sed "s#\.yaml#.tf#g")"' \
 | sh \
&& cat <<EOS > "${CHART_TF_DIR}/variables.tf"
variable "repo_chart" {
  type = string
  default = "${REPO_CHART}"
}
variable "namespace" {}
EOS

# Adjustments ...
find "${CHART_TF_DIR}" -type f | xargs -i sed -i'' '/^$/d' {}
find "${CHART_TF_DIR}" -type f | xargs sed -ri'' 's#^resource "(kubernetes_)([^"].*)" "\$\$\{var\.repo_chart\}_(.*)$#resource "\1\2" "\2_\3#g'
find "${CHART_TF_DIR}" -type f | xargs sed -ri'' 's#\$\$\{var\.#${var.#g;s#empty_dir = \{\}#empty_dir {}#g'

# Validations ...
(cd "${CHART_TF_DIR}" && terraform fmt && terraform init && terraform validate)

PROVIDER_DIR="$(python3 -c 'import os; print(os.path.relpath(".", "'${CHART_TF_DIR}'"))')"
cat <<EOS
# Suggested command(s):
#
# ln -nsf "${PROVIDER_DIR}/provider.tf" "${CHART_TF_DIR}" && NS=some-namespace && (cd "${CHART_TF_DIR}" \\
#   && kubectl create namespace \$NS \\
#   && terraform apply -var=namespace=\$NS \\
# ;)
EOS