kubevela/docs/examples/app-with-policy/gc-policy/reverse-dependency.md

How to garbage collect resources in the order of dependency

If you want to garbage collect resources in the order of reverse dependency, you can add order: dependency in the garbage-collect policy.

Notice that this order policy is only valid for the resources that are created in the components.

In the following example, component test1 depends on test2, and test2 need the output from test3.

So the order of deployment is: test3 -> test2 -> test1.

When we add order: dependency in garbage-collect policy and delete the application, the order of garbage collect is: test1 -> test2 -> test3.

apiVersion: core.oam.dev/v1beta1
kind: Application
metadata:
  name: gc-dependency
  namespace: default
spec:
  components:
  - name: test1
    type: webservice
    properties:
      image: crccheck/hello-world
      port: 8000
    dependsOn:
      - "test2"
  - name: test2
    type: webservice
    properties:
      image: crccheck/hello-world
      port: 8000
    inputs:
      - from: test3-output
        parameterKey: test
  - name: test3
    type: webservice
    properties:
      image: crccheck/hello-world
      port: 8000
    outputs:
      - name: test3-output
        valueFrom: output.metadata.name
  
  policies:
    - name: gc-dependency
      type: garbage-collect
      properties:
        order: dependency