Interpolate environment variables

Any visible (Param) string field can reference an environment variable with ${env:VAR} — metadata names, image.name/image.tag, fqdn, a git source, an inline dockerfile, destination, limits, and plain env_vars values. References are resolved at apply, just before the value is pushed; an unset variable is then an error (no silent fallback to ""). validate, plan and explore keep the reference unresolved, so they need no variable set.

metadata:
  environment: "${env:DEPLOY_ENV}"
spec:
  image:
    tag: "${env:IMAGE_TAG}"
  fqdn: "https://${env:PUBLIC_HOST}"

Param fields are visible in plan/apply output once resolved. Never put a secret in a Param field — use value_secret (see Manage secrets) for sensitive values.