a bit o' spruce, from http://play.spruce.cf

spruce.json

{"flavor":"1.29.0","prune":["meta"],"env":["HOME=/home/user"],"cherry_pick":[],"yaml":[{"filename":"file1.yml","contents":"apiVersion: v1\nkind: List\nmetadata:\n  name: istio-namespace-labels\nitems:\n  - metadata:\n      name: armada\n    .: (( inject namespace-template ))\n  - metadata:\n      name: satellite-link-api\n    .: (( inject namespace-template ))\n  - metadata:\n      name: monitoring\n    .: (( inject namespace-template ))\n  - metadata:\n      name: sonarqube\n    .: (( inject namespace-template ))\n  - metadata:\n      name: satellite-link-tests\n    .: (( inject namespace-template ))\n\nnamespace-template:\n  apiVersion: v1\n  kind: Namespace\n  metadata:\n    labels:\n      istio.io/rev: \"{{ armada.armada-istio-version-configmap.REVISION }}\"\n\n"}],"skip_eval":false,"fallback_append":false,"go_patch":false,"debug":false,"trace":false}