コンテナイメージ名を変換したい

input.yml

apiVersion: apps/v1
kind: Deployment
metadata:
  labels:
    app: demo
  name: demo
spec:
  replicas: 1
  selector:
    matchLabels:
      app: demo
  template:
    metadata:
      labels:
        app: demo
    spec:
      containers:
      - image: making/hello-tanzu
        name: hello-tanzu
      - image: making/sidecar
        name: sidecar    

overlay.yml

#@ load("@ytt:overlay", "overlay")

#@ def replace_image(x):
#@   container = dict(**x)
#@   image = container["image"]
#@   rest = image.split("/")[-2:]
#@   container["image"] = "/".join(["harbor.example.com"] + rest)
#@   return container
#@ end

#@overlay/match by=overlay.subset({"kind":"Deployment","metadata":{"name":"demo"}})
---
spec:
 template:
   spec:
     containers:
     #@overlay/match by=overlay.all, expects="1+"
     - #@overlay/replace via=lambda a,b: replace_image(a)
       image: