helm-docs

The helm-docs tool generates automatic documentation from helm charts into a markdown file. The resulting file contains metadata about the chart and a table with all of your charts' values, their defaults, and an optional description parsed from comments.

The markdown generation is entirely gotemplate driven. The tool parses metadata from charts and generates a number of sub-templates that can be referenced in a template file (by default README.md.gotmpl). If no template file is provided, the tool has a default internal template that will generate a reasonably formatted README.

Installation

helm-docs can be installed using homebrew:

brew install norwoodj/tap/helm-docs

This will download and install the latest release of the tool.

To build from source in this repository:

cd cmd/helm-docs
go build

Usage

To run and generate documentation into READMEs for all helm charts within or recursively contained by a directory:

helm-docs
# OR
helm-docs --dry-run # prints generated documentation to stdout rather than modifying READMEs

The tool searches recursively through subdirectories of the current directory for Chart.yaml files and generates documentation for every chart that it finds.

Available Templates

The templates generated by the tool are shown below, and can be included in your README.md.gotmpl file like so:

{{ template "template-name" . }}

Name	Description
chart.header	The main heading of the generated markdown file
chart.description	A description line containing the description field from the chart's Chart.yaml file, or "" if that field is not set
chart.version	The version field from the chart's Chart.yaml file
chart.versionLine	A text line stating the current version of the chart
chart.sourceLink	The home link from the chart's Chart.yaml file, or "" if that field is not set
chart.sourceLinkLine	A text line with the home link from the chart's Chart.yaml file, or "" if that field is not set
chart.requirementsHeader	The heading for the chart requirements section
chart.requirementsTable	A table of the chart's required sub-charts
chart.requirementsSection	A section headed by the requirementsHeader from above containing the requirementsTable from above or "" if there are no requirements
chart.valuesHeader	The heading for the chart values section
chart.valuesTable	A table of the chart's values parsed from the values.yaml file (see below)
chart.valuesSection	A section headed by the valuesHeader from above containing the valuesTable from above or "" if there are no values

For an example of how these various templates can be used in a README.md.gotmpl file to generate a reasonable markdown file, look at the charts in example-charts.

If there is no README.md.gotmpl (or other specified gotmpl file) present, the default template is used to generate the README. That template looks like so:

{{ template "chart.header" . }}
{{ template "chart.description" . }}

{{ template "chart.versionLine" . }}

{{ template "chart.sourceLinkLine" . }}

{{ template "chart.requirementsSection" . }}

{{ template "chart.valuesSection" . }}

The tool includes the sprig templating library, so those functions can be used in the templates you supply.

values.yaml metadata

This tool can parse descriptions and defaults of values from values.yaml files. The defaults are pulled directly from the yaml in the file. Descriptions can be added for parameters by specifying the full path of the value and a particular comment format. I invite you to check out the example-charts to see how this is done in practice. In order to add a description for a parameter you need only put a comment somewhere in the file of the format:

controller:
  publishService:
    # controller.publishService.enabled -- Whether to expose the ingress controller to the public world
    enabled: false

  # controller.replicas -- Number of nginx-ingress pods to load balance between
  replicas: 2

The descriptions will be picked up and put in the table in the README. The comment need not be near the parameter it explains, although this is probably preferable.

Note: if the value in question contains any . characters, that section of the path must be quoted e.g.

service:
  annotations:
    # ingress.annotations."external-dns.alpha.kubernetes.io/hostname" -- Hostname to be assigned to the ELB for the service
    external-dns.alpha.kubernetes.io/hostname: stupidchess.jmn23.com

nil values

If you would like to define a key for a value, but leave the default empty, you can still specify a description for it as well as a type. Like so:

controller:
  # controller.replicas -- (int) Number of nginx-ingress pods to load balance between
  replicas:

This could be useful when wanting to enforce user-defined values for the chart, where there are no sensible defaults.