render-helm-chart

README

render-helm-chart

Overview

The render-helm-chart function renders a local or remote Helm chart.

Helm is a package manager for kubernetes that uses a packaging format called charts. A chart is a collection of files within a directory, which contain templates, CRDs, values, and metadata.

This function renders charts by using the helm template command, so that helm charts can be rendered without needing to install the helm binary directly.

You can learn more about helm here and more about helm charts here.

Usage

This function can be used with any KRM function orchestrators such to render a specified helm chart. To run the function with kustomize, the network field is needed for remote charts and the mounts field is needed for local charts.

FunctionConfig

There are 2 kinds of functionConfig supported by this function:

• ConfigMap
• A custom resource of kind RenderHelmChart

Many of the fields in each functionConfig map directly to flag options provided by helm template.

ConfigMap

To use a ConfigMap as the functionConfig, the desired parameters must be specified in the data field:

data:
  chartHome: string
  configHome: string
  name: string
  version: string
  repo: string
  releaseName: string
  namespace: string
  nameTemplate: string
  includeCRDs: string
  skipTests: string
  valuesFile: string

Field	Description	Example
chartHome	A filepath to a directory of charts. The function will look for the chart in this local directory before attempting to pull the chart from a specified repo. Defaults to "tmp/charts". When run in a container, this path MUST have the prefix "tmp/".	tmp/charts
configHome	Defines a value that the function should pass to helm via the HELM_CONFIG_HOME environment variable. If omitted, {tmpDir}/helm is used, where {tmpDir} is some temporary directory created by the function for the benefit of helm. This option is not supported when running in a container. It is supported only in exec mode (e.g. with kustomize)	/tmp/helm/config
name	The name of the chart	minecraft
version	The version of the chart	3.1.3
repo	A URL locating the chart on the internet	https://itzg.github.io/minecraft-server-charts
releaseName	Replaces RELEASE_NAME in the chart template output	test
namespace	Sets the target namespace for a release (.Release.Namespace in the template)	my-namespace
nameTemplate	Specify the template used to name the release	gatekeeper
includeCRDs	Specifies if Helm should also generate CustomResourceDefinitions. Legal values: "true", "false" (default).	"true"
skipTests	If set, skip tests from templated output. Legal values: "true", "false" (default).	"true"
valuesFile	valuesFile is a remote or local file path to a values file to use instead of the default values that accompanied the chart. The default values are in '{chartHome}/{name}/values.yaml', where chartHome and name are the parameters defined above.	Using a local values file: path/to/your/values.yaml Using a remote values file: https://raw.githubusercontent.com/config-sync-examples/helm-components/main/cert-manager-values.yaml

RenderHelmChart

A functionConfig of kind RenderHelmChart has the following supported parameters:

helmGlobals:
  chartHome: string
  configHome: string
helmCharts:
- chartArgs: 
    name: string
    version: string
    repo: string
  templateOptions:
    apiVersions: []string
    releaseName: string
    namespace: string
    nameTemplate: string
    includeCRDs: bool
    skipTests: bool
    values:
      valuesFiles: []string
      valuesInline: map[string]interface{}
      valuesMerge: string

Field	Description	Example
helmGlobals	Parameters applied to all Helm charts
helmCharts	An array of helm chart parameters
chartArgs	Arguments that describe the chart being rendered.
templateOptions	A collection of fields that map to flag options of helm template.
chartHome	A filepath to a directory of charts. The function will look for the chart in this local directory before attempting to pull the chart from a specified repo. Defaults to "tmp/charts". When run in a container, this path MUST have the prefix "tmp/".	tmp/charts
configHome	Defines a value that the function should pass to helm via the HELM_CONFIG_HOME environment variable. If omitted, {tmpDir}/helm is used, where {tmpDir} is some temporary directory created by the function for the benefit of helm. This option is not supported when running in a container. It is supported only in exec mode (e.g. with kustomize)	/tmp/helm/config
name	The name of the chart	minecraft
version	The version of the chart	3.1.3
repo	A URL locating the chart on the internet	https://itzg.github.io/minecraft-server-charts
apiVersions	Kubernetes api versions used for Capabilities.APIVersions	acme.cert-manager.io/v1
releaseName	Replaces RELEASE_NAME in the chart template output	test
namespace	Sets the target namespace for a release (.Release.Namespace in the template)	my-namespace
nameTemplate	Specify the template used to name the release	gatekeeper
includeCRDs	Specifies if Helm should also generate CustomResourceDefinitions. Legal values: "true", "false" (default).	"true"
skipTests	If set, skip tests from templated output. Legal values: "true", "false" (default).	"true"
values	Values to use instead of the default values that accompany the chart. This can be defined inline or in a file.
valuesInline	Values defined inline to use instead of default values that accompany the chart	global:   enabled: false tests:   enabled: false
valuesFiles	Remote or local filepaths to use instead of the default values that accompanied the chart. The default values are in '{chartHome}/{name}/values.yaml', where chartHome and name are the parameters defined above.	Using a local values file: path/to/your/values.yaml Using a remote values file: https://raw.githubusercontent.com/config-sync-examples/helm-components/main/cert-manager-values.yaml
valuesMerge	ValuesMerge specifies how to treat ValuesInline with respect to ValuesFiles. Legal values: 'merge', 'override' (default), 'replace'.	replace