Kubernetes deployment strategy using Kustomize and a few basic tools. Replaces helm charts with simple tooling solutions.

kustomize-deploy.sh

# Kustomize based apply workflow. Requires jq, yq, kubectl, kustomize, mustache.
#
# Expected variables
# - namespace   Namespace for all resources.
# - release     A unique name to give to this collection of manifests.
# - revision    Release revision.
# - images      Image replacements.
# - variables   Variable replacements.
#
# Example inputs:
# namespace=pr123
# release=app-pr123
# target=review
# revision=ab331a
# images='[{ "name": "nginx", "newTag": "latest" }]'
# variables='{"host": "pr123.example.com"}'
set -e
echo "deploying $release into namespace $namespace using overlay overlays/$target"

mkdir -p build
cd build

cat > kustomization.yaml <<EOF
namespace: $namespace
namePrefix: $release-

commonLabels:
  deliverybot.io/release: $release

commonAnnotations:
  deliverybot.io/target: $target
  deliverybot.io/revision: $revision

images: $images

resources:
- ../overlays/$target
EOF

cat > namespace.yaml <<EOF
apiVersion: v1
kind: Namespace
metadata:
  name: $namespace
EOF

echo $variables > variables.yaml
yq --yaml-output -s add ../overlays/$target/variables.yaml variables.yaml > merged.yaml

kustomize build | mustache merged.yaml - > build.yaml

kubectl apply -f namespace.yaml
kubectl apply -f build.yaml --prune --selector deliverybot.io/release=$release --prune-whitelist=core/v1/Namespace

kustomize-remove.sh

# Kustomize based deletion workflow. Requires jq, kubectl.
#
# Expected variables:
# - namespace   Namespace for the release.
# -
# - release     A unique name to give to this collection of manifests.
# - delete      Resource delete whitelist.
#
# Example inputs:
# namespace=pr123
# release=app-pr123
# delete='["deployment", "service", "ingress", "namespace"]'
set -e

echo "removing $release with resources $delete"

resources=$(echo $delete | jq -r 'join(",")')
kubectl --namespace $namespace delete $resources --selector deliverybot.io/release=$release

remove_namespace=$(echo $delete | jq 'contains(["namespace"])')
if [ "$remove_namespace" = "true" ]; then
  kubectl delete ns/$namespace || exit 0
fi