Kustomize Replacements Example

README.md

Provides a simple way of replacing ingress annotations with values already defined elsewhere. Output example:

apiVersion: v1
kind: Namespace
metadata:
  name: jeffspace
---
apiVersion: v1
kind: Service
metadata:
  name: jeffnet
  namespace: jeffspace
---
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  annotations:
    nginx.ingress.kubernetes.io/service-upstream: "true"
    nginx.ingress.kubernetes.io/upstream-vhost: jeffnet.jeffspace.svc.cluster.local
  name: jeffnet-ingress
  namespace: jeffspace
spec:
  ingressClassName: nginx-int
  rules:
  - host: api.jeff.net
    http:
      paths:
      - backend:
          service:
            name: jeffnet
            port:
              number: 80
        path: /
        pathType: Prefix

ingress.yaml

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  annotations:
    nginx.ingress.kubernetes.io/upstream-vhost: x.y.svc.cluster.local
    nginx.ingress.kubernetes.io/service-upstream: "true"
  name: jeffnet-ingress
  namespace: jeffspace
spec:
  ingressClassName: nginx-int
  rules:
    - host: api.jeff.net
      http:
        paths:
          - backend:
              service:
                name: jeffnet
                port:
                  number: 80
            path: /
            pathType: Prefix

kustomization.yaml

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

resources:
  - namespace.yaml
  - service.yaml
  - ingress.yaml

replacements:
  - source:
      kind: Service
      fieldPath: metadata.name
    targets:
      - select:
          kind: Ingress
        fieldPaths:
          - metadata.annotations.[nginx.ingress.kubernetes.io/upstream-vhost]
        options: { delimiter: ".", index: 0 }
  - source:
      kind: Namespace
      fieldPath: metadata.name
    targets:
      - select:
          kind: Ingress
        fieldPaths:
          - metadata.annotations.[nginx.ingress.kubernetes.io/upstream-vhost]
        options: { delimiter: ".", index: 1 }

namespace.yaml

apiVersion: v1
kind: Namespace
metadata:
  name: jeffspace

service.yaml

apiVersion: v1
kind: Service
metadata:
  name: jeffnet
  namespace: jeffspace