Unable to override port values using kustomization in k8s

I am doing some practices. one of the test cases i tried to override the values of port value. while doing that getting an error as replace operation does not apply: doc is missing key: /spec/ports/port: missing value.

patches:
  - target:
      kind: Service
      name: cdq-ui-service
    patch: |
      - op: replace
        path: /spec/ports/0/port
        value: 8080

while applying kustomization in Kubernetes with the patch. that path will be override the port value.

You are trying to modify /spec/ports/port, but there is no such path in a Kubernetes service. Recall that a service looks like this:

apiVersion: v1
kind: Service
metadata:
  name: my-service
spec:
  selector:
    app.kubernetes.io/name: MyApp
  ports:
    - protocol: TCP
      port: 80
      targetPort: 9376

The path /spec/ports is a list, not a dictionary. You could patch /spec/ports/0/port:

apiVersion: kustomize.config.k8s.io/v1beta1
kind: Kustomization

resources:
- service.yaml

patches:
  - target:
      kind: Service
      name: my-service
    patch: |
      - op: replace
        path: /spec/ports/0/port
        value: 8080

Which would result in:

apiVersion: v1
kind: Service
metadata:
  name: my-service
spec:
  ports:
  - port: 8080
    protocol: TCP
    targetPort: 9376
  selector:
    app.kubernetes.io/name: MyApp