Kubernetes Custom Resource API Reference Docs generator

If you have a project that is providing Custom Resource Definitions and wanted to generate
API Reference Docs like this this tool is for you.

Alternatives

This project has inspired creation of the following projects:

• Kubernetes reference-docs generator:
  used in official Kubernetes component reference docs

• crd-ref-docs by Elastic: A fresh implementation
  of this project.

• If you're an open source project, consider exposing your
  CRD API Reference via https://doc.crds.dev/ without much effort.

Current Users

• Knative API reference docs
• FluxCD API reference docs
• Argo CD operator API reference docs
• Contour ingress controller API reference docs
• Kubeflow API reference docs
• cert-manager API reference docs
• Open Service Mesh API reference docs
• PlanetScale Vitess Operator API reference docs
• Agones API reference docs
• Gardener API reference docs
• New Relic Alert Manager API reference docs
• Antrea API reference docs
• kube-green API reference docs
• Azure Service Operator supported resources
• NGINX Gateway Fabric API reference docs
• [[ADD YOUR PROJECT HERE]]

Also some forks:

• elastic/crd-ref-docs: A fresh re-implementation inspired
  by this project that supports AsciiDoc. Used by Elastic Cloud on Kubernetes API reference docs.

Why

Normally you would want to use the same docs generator as Kubernetes API
reference, but here's why I wrote a different parser/generator:

1. Today, Kubernetes API does not provide OpenAPI specs for CRDs (e.g.
   Knative), therefore the gen-apidocs
   generator used by Kubernetes won't work.

2. Even when Kubernetes API starts providing OpenAPI specs for CRDs, your CRD
   must have a validation schema (e.g. Knative API doesn't!)

3. Kubernetes gen-apidocs parser relies on running a kube-apiserver and
   calling /apis endpoint to get OpenAPI specs to generate docs. This tool
   doesn't need that!

How

This is a custom API reference docs generator that uses the
k8s.io/gengo project to parse types and
generate API documentation from it.

Capabilities of this tool include:

• Doesn't depend on OpenAPI specs, or kube-apiserver, or a running cluster.
• Relies only on the Go source code (pkg/apis/**/*.go) to parse API types.
• Can link to other sites for external APIs. For example, if your types have a
  reference to Kubernetes core/v1.PodSpec, you can link to it.
• Configurable settings to hide certain fields or types
  entirely from the generated output.
• Either output to a file or start a live http-server (for rapid iteration).
• Supports markdown rendering from godoc type, package and field comments.

Try it out

1. Clone this repository.

2. Make sure you have go1.11+ installed. Then run go build, you should get a
   gen-crd-api-reference-docs binary executable in the current directory.

3. Clone a Knative repository, set GOPATH correctly,
   and call the compiled binary within that directory.

   # go into a repository root with GOPATH set. (I use my own script
   # goclone(1) to have a separate GOPATH for each repo I clone.)
   $ goclone knative/build
   
   $ /path/to/gen-crd-api-reference-docs \
       -config "/path/to/example-config.json" \
       -api-dir "github.com/knative/build/pkg/apis/build/v1alpha1" \
       -out-file docs.html

4. Visit docs.html to view the results.

This is not an official Google project. See LICENSE.