README.md

Supporting Custom Resources (defined by a CRD)

This tutorial shows how to add transformer configurations to support a custom resource.

Create a workspace by

DEMO_HOME=$(mktemp -d)

Adding a custom resource

Consider a CRD of kind MyKind with fields

• .spec.secretRef.name reference a Secret
• .spec.beeRef.name reference an instance of CRD Bee
• .spec.containers.command as the list of container commands
• .spec.selectors as the label selectors

Add the following file to configure the transformers for the above fields

mkdir $DEMO_HOME/kustomizeconfig
cat > $DEMO_HOME/kustomizeconfig/mykind.yaml << EOF

commonLabels:
- path: spec/selectors
  create: true
  kind: MyKind

nameReference:
- kind: Bee
  fieldSpecs:
  - path: spec/beeRef/name
    kind: MyKind
- kind: Secret
  fieldSpecs:
  - path: spec/secretRef/name
    kind: MyKind

varReference:
- path: spec/containers/command
  kind: MyKind
- path: spec/beeRef/action
  kind: MyKind

EOF

Apply config

Create a file with some resources that includes an instance of MyKind:

cat > $DEMO_HOME/resources.yaml << EOF
apiVersion: v1
kind: Secret
metadata:
  name: crdsecret
data:
  PATH: YmJiYmJiYmIK
---
apiVersion: v1beta1
kind: Bee
metadata:
  name: bee
spec:
  action: fly
---
apiVersion: jingfang.example.com/v1beta1
kind: MyKind
metadata:
  name: mykind
spec:
  secretRef:
    name: crdsecret
  beeRef:
    name: bee
    action: \$(BEE_ACTION)
  containers:
  - command:
    - "echo"
    - "\$(BEE_ACTION)"
    image: myapp
EOF

Create a kustomization referring to it:

cat > $DEMO_HOME/kustomization.yaml << EOF
resources:
- resources.yaml

namePrefix: test-

commonLabels:
  foo: bar

vars:
- name: BEE_ACTION
  objref:
    kind: Bee
    name: bee
    apiVersion: v1beta1
  fieldref:
    fieldpath: spec.action
EOF

Use the customized transformer configurations by specifying them in the kustomization file:

cat >> $DEMO_HOME/kustomization.yaml << EOF
configurations:
- kustomizeconfig/mykind.yaml
EOF

Run kustomize build and verify that the namereference is correctly resolved.

test 2 == \
$(kustomize build $DEMO_HOME | grep -A 2 ".*Ref" | grep "test-" | wc -l); \
echo $?    

Run kustomize build and verify that the vars correctly resolved.

test 0 == \
$(kustomize build $DEMO_HOME | grep "BEE_ACTION" | wc -l); \
echo $?