helm-tpl

Various helm templates to provide useful functions in helm charts.

• jsonpatch
• toPrettyRawJson
• tplYaml

jsonpatch

JSON Patch in a Helm Named Template

Usage

Copy _jsonpatch.tpl to your helm chart templates/ directory

Call the jsonpatch named template:

• input: a map with 2 keys:
  • doc: interface{} valid JSON document
  • patch: []interface{} valid JSON Patch document
• output: JSON encoded map with 1 key:
  • doc: interface{} patched json result

Example

values.yaml:

pod:
  apiVersion: v1
  kind: Pod
  metadata:
    name: nginx
  spec:
    containers:
    - name: nginx
      image: nginx:latest
      ports:
      - containerPort: 80

patchPod:
- op: replace
  path: /spec/containers/0/image
  value: nginx:alpine
- op: add
  path: /spec/containers/0/ports/-
  value:
    containerPort: 8080

templates/pod.yaml:

{{ get (include "jsonpatch" (dict "doc" .Values.pod "patch" .Values.patchPod) | fromJson) "doc" | toYaml }}

helm template output:

---
# Source: jsonpatch-example/templates/pod.yaml
apiVersion: v1
kind: Pod
metadata:
  name: nginx
spec:
  containers:
  - image: nginx:alpine
    name: nginx
    ports:
    - containerPort: 80
    - containerPort: 8080

Try it by running ./jsonpatch/example/template.sh

toPrettyRawJson

Copy _toPrettyRawJson.tpl to your helm chart templates/ directory

Pretty prints using toPrettyJson and unescapes HTML entities for &, <, and >

Try it by running ./toPrettyRawJson/example/template.sh

tplYaml

Copy _jsonpatch.tpl and _tplYaml.tpl to your helm chart templates/ directory

Call the tplYaml named template:

• input: a map with 2 keys:
  • doc: interface{} valid JSON document
  • ctx: interface{} context to pass to template function
• output: JSON encoded map with 1 key:
  • doc: interface{} patched json result

Example

values.yaml:

name: nginx
ports:
  http: 80
  https: 443

pod:
  apiVersion: v1
  kind: Pod
  metadata:
    name:
      $tplYaml: >-
        {{ .Values.name | quote }}
  spec:
    containers:
    - name:
        $tplYaml: >-
          {{ .Values.name | quote }}
      image: nginx:latest
      ports:
      - $tplYamlSpread: |-
          {{- range $k, $v := .Values.ports }}
          - name: {{ $k | quote }}
            containerPort: {{ $v }}
          {{- end }}

templates/pod.yaml:

{{ get (include "tplYaml" (dict "doc" .Values.pod "ctx" .) | fromJson) "doc" | toYaml }}

helm template output:

---
# Source: tplYaml-example/templates/pod.yaml
apiVersion: v1
kind: Pod
metadata:
  name: nginx
spec:
  containers:
  - image: nginx:latest
    name: nginx
    ports:
    - containerPort: 80
      name: http
    - containerPort: 443
      name: https

Try it by running ./tplYaml/example/template.sh