config.yml

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

apps:
#@ for app in data.values.traefik.ingress_routes:
- #@ app
#@ end

defaults.yml

#@data/values
---
traefik:
  ingress_routes:
  - name: foo
    insecure: true
  - name: bar
    insecure: false
  - name: ree

values-ensure-insecure-attr.yml

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

#@data/values
---
traefik:
  ingress_routes:
    #@overlay/match by=overlay.not_op(overlay.subset({"insecure": True})), expects="0+"
    -
      #@overlay/match missing_ok=True
      insecure: false