jsonpatch.md

示例: 应用 json patch（json补丁）

kustomization文件支持通过JSON patches来修改已有的资源.

下面的例子将会使用这个功能对Ingress加以修改.

首先，创建一个包含ingress的kustomization文件.

DEMO_HOME=$(mktemp -d)

cat <<EOF >$DEMO_HOME/kustomization.yaml
resources:
- ingress.yaml
EOF

cat <<EOF >$DEMO_HOME/ingress.yaml
apiVersion: networking.k8s.io/v1beta1
kind: Ingress
metadata:
  name: my-ingress
spec:
  rules:
  - host: foo.bar.com
    http:
      paths:
      - backend:
          serviceName: my-api
          servicePort: 80
EOF

定义一个JSON patch文件，以更新Ingress对象的2个字段:

• 把 host 从 foo.bar.com 改为 foo.bar.io
• 把 servicePort 从 80 改为 8080

cat <<EOF >$DEMO_HOME/ingress_patch.json
[
  {"op": "replace", "path": "/spec/rules/0/host", "value": "foo.bar.io"},
  {"op": "replace", "path": "/spec/rules/0/http/paths/0/backend/servicePort", "value": 8080}
]
EOF

JSON patch 也可以写成 YAML 的格式.该例子顺便展示了“添加”操作：

cat <<EOF >$DEMO_HOME/ingress_patch.yaml
- op: replace
  path: /spec/rules/0/host
  value: foo.bar.io

- op: add
  path: /spec/rules/0/http/paths/-
  value:
    path: '/test'
    backend:
      serviceName: my-test
      servicePort: 8081
EOF

在kustomization.yaml文件中增加 patchesJson6902 字段，以应用该补丁

cat <<EOF >>$DEMO_HOME/kustomization.yaml
patchesJson6902:
- target:
    group: networking.k8s.io
    version: v1beta1
    kind: Ingress
    name: my-ingress
  path: ingress_patch.json
EOF

运行 kustomize build $DEMO_HOME, 在输出那里确认 host 已经被正确更新.

test 1 == \
  $(kustomize build $DEMO_HOME | grep "host: foo.bar.io" | wc -l); \
  echo $?

运行 kustomize build $DEMO_HOME, 在输出那里确认 servicePort 已经被正确更新.

test 1 == \
  $(kustomize build $DEMO_HOME | grep "servicePort: 8080" | wc -l); \
  echo $?

如果 patch 是YAML格式的，就能正确解析:

cat <<EOF >>$DEMO_HOME/kustomization.yaml
patchesJson6902:
- target:
    group: networking.k8s.io
    version: v1beta1
    kind: Ingress
    name: my-ingress
  path: ingress_patch.yaml
EOF

运行 kustomize build $DEMO_HOME, 在输出那里确认有 /test 这个路径.

test 1 == \
  $(kustomize build $DEMO_HOME | grep "path: /test" | wc -l); \
  echo $?