INSIOS/generic-chart

A generic Helm chart for any application with any number of resources of any kind.

Note

This README is currently under construction.

Description

This chart contains a single template for rendering any Kubernetes manifests specified in the chart's values, along with a small set of helpers, allowing you to describe almost any application structure.

With this chart, you can deploy applications with any resources, including unique CRDs specific to your cluster. Additionally, the size of the chart—and therefore the sh.helm.release.* secrets—will remain minimal, as it won't include any unused templates, which is often the case with other generic charts.

TL;DR

helm upgrade --install myapp \
    oci://ghcr.io/insios/helm/generic \
    -f ./values.yaml

OR

helm upgrade --install myapp \
    oci://ghcr.io/insios/helm/generic \
    -f ./myapp.generic.yaml \
    -f ./values.yaml

OR

helm upgrade --install myapp \
    oci://ghcr.io/insios/helm/generic \
    -f https://raw.githubusercontent.com/insios/generic-chart/refs/tags/tpl-1.0.0/templates/starter/starter.generic.yaml \
    -f ./values.yaml

Chart values

Application metadata

See https://kubernetes.io/docs/concepts/overview/working-with-objects/common-labels/#labels

Key	Type	Default	Description
app	object	{}	Application metadata
app.name	string	nil	.Release.Name if empty
app.version	string	nil
app.instance	string	nil	.Release.Name if empty
app.partOf	string	nil
app.environment	string	nil

Application components and their resources

List of the application components and their resources

Key	Type	Default	Description
components	object or list	{}	List of the application components
components[].componentName	string	nil
components[].resources	object or list	{}	List of the component resources
components[].resources[].resourceName	string	nil
components[].resources[].manifest	object	{}	See reference

Snippets

Snippets can be used anywhere within the resource manifest hierarchy.

Key	Type	Default	Description
snippets	object	{}	Named list of the manifest's snippets

Special keys

$disabled

It can be placed in the component definition, resource definition, or anywhere within the manifest hierarchy. If evaluated to true, the entire object will be excluded from manifest's rendering.

Examples:

# ...
components:
  # ...
  - componentName: 'cron'
    $disabled: '{{ eq "development" .Values.app.environment }}'
    resources:
      # ...
      - resourceName: 'sendEmails'
        manifest:
          apiVersion: batch/v1
          kind: CronJob
          # ...
      # ...
  # ...
# ...

# ...
components:
  # ...
  - componentName: 'back'
    resources:
      # ...
      - resourceName: ''
        $disabled: '{{ not .Values.ingress.enabled }}'
        manifest:
          apiVersion: networking.k8s.io/v1
          kind: Ingress
          # ...
      # ...
  # ...
# ...

# ...
components:
  # ...
  - componentName: 'back'
    resources:
      # ...
      - resourceName: ''
        manifest:
          apiVersion: apps/v1
          kind: Deployment
          metadata:
            # ...
          spec:
            # ...
            strategy:
              $disabled: true
              type: Recreate
            # ...
      # ...
  # ...
# ...

$snippets

It can be placed anywhere within the manifest hierarchy. All snippets from this list will be merged into the object before processing any other special keys.

Examples:

components:
  # ...
  - componentName: 'back'
    resources:
      # ...
      - resourceName: ''
        manifest:
          $snippets:
            - manifestCommon
            - manifestDeployment
          spec:
            replicas: 2
            template:
              spec:
                containers:
                  - name: back-api
                    $snippets:
                      - containerCommon
                      - containerBack
                      - containerHttp
      - resourceName: 'worker'
        manifest:
          $snippets:
            - manifestCommon
            - manifestJob
          spec:
            template:
              spec:
                containers:
                  - name: back-worker
                    $snippets:
                      - containerCommon
                      - containerBack
                    command: ['worker']
      # ...
  - componentName: 'front'
    resources:
      # ...
      - resourceName: ''
        manifest:
          $snippets:
            - manifestCommon
            - manifestDeployment
          spec:
            replicas: 1
            template:
              spec:
                containers:
                  - name: front-www
                    $snippets:
                      - containerCommon
                      - containerFront
                      - containerHttp
      # ...
  # ...

snippets:
  # ...
  manifestCommon:
    metadata:
      $name: 'fullResourceNameStr'
      $labels: 'resourceLabelsMap'
  manifestDeployment:
    apiVersion: apps/v1
    kind: Deployment
    spec:
      selector:
        $matchLabels: 'selectorLabelsMap'
      template:
        $snippets: ['podTemplateCommon']
  manifestJob:
    apiVersion: batch/v1
    kind: Job
    spec:
      template:
        $snippets: ['podTemplateCommon']
  # ...
  podTemplateCommon:
    metadata:
      $labels: 'resourceLabelsMap'
    spec:
      imagePullSecrets:
        - name: my-registry-auth
  # ...
  containerCommon:
    imagePullPolicy: IfNotPresent
  containerHttp:
    ports:
      - name: http
        containerPort: 80
        protocol: TCP
  containerBack:
    $image: 'tplStr: "myrepo/myapp-back:{{ (.Values.back).version }}"'
  containerFront:
    $image: 'tplStr: "myrepo/myapp-front:{{ (.Values.front).version }}"'
  # ...

$[anyKey] (use helper template)

The full definition of using a helper template looks like:

$anyKey:
  $disabled: false
  tplName: 'fullResourceNameStr'
  tplParam: ['dpl', 'back']
  dstKey: 'name'
  valType: 'Str'
  addEmpty: false

Key	Type	Default	Description
$disabled	bool or string	false
tplName	string	nil	Helper template name
tplParam	any	nil	Helper template parameter (if needed)
dstKey	string	key without '$'	Destination key for the value
valType	string	end of tplName	Type of a destination key value - Str, Int, Flt, Bln, Map or Lst
addEmpty	bool	false	Add, even if the result is empty

Short notation with parameters:

$anyKey: 'fullResourceNameStr: ["dpl", "back"]'

Short notation without parameters:

$anyKey: 'fullResourceNameStr'

Available helper templates

appNameStr

The name of the application: .Values.app.name, or, if it is empty - .Release.Name.

appInstanceStr

The instance of the application: .Values.app.instance, or, if it is empty - .Release.Name.

fullComponentNameStr

The full name of the component in a form appInstanceStr[-componentName].

fullResourceNameStr

The full name of the resource in a form appInstanceStr[-componentName][-resourceName].

If no parameter is provided, the full name of the current resource will be used.

If a parameter is an array with one element, that element will be used as the resourceName.

If a parameter is an array with two elements, the first element will be used as the resourceName, and the second element will be used as the componentName.

selectorLabelsMap

The set of resource labels used for POD selection.

The parameter is used in the same way as in fullResourceNameStr.

resourceLabelsMap

The full set of resource labels.

The parameter is used in the same way as in fullResourceNameStr.

tplXxx

Name	Return type
tplStr	string
tplInt	integer
tplFlt	float
tplBln	boolean
tplMap	object
tplLst	list

Examples:

$replicas: 'tplInt: "{{ .Values.replicaCount }}"'
$extraLabels:
   tplName: tplMap
   tplParam: '{{ .Values.podLabels }}'
   dstKey: 'labels'

Examples

See templates