api

api

The canonical location of the OpenShift API definition. This repo holds the API type definitions and serialization code used by openshift/client-go

defining new APIs

When defining a new API, please follow the OpenShift API conventions, and then follow the instructions below to regenerate CRDs (if necessary) and submit a pull request with your new API definitions and generated files.

generating CRD schemas

Since Kubernetes 1.16, every CRD created in apiextensions.k8s.io/v1 is required to have a structural OpenAPIV3 schema. The schemas provide server-side validation for fields, as well as providing the descriptions for oc explain. Moreover, schemas ensure structural consistency of data in etcd. Without it anything can be stored in a resource which can have security implications. As we host many of our CRDs in this repo along with their corresponding Go types we also require them to have schemas. However, the following instructions apply for CRDs that are not hosted here as well.

These schemas are often very long and complex, and should not be written by hand. For OpenShift, we provide Makefile targets in build-machinery-go which generate the schema, built on upstream's controller-gen tool.

If you make a change to a CRD type in this repo, simply calling make update-codegen-crds should regenerate all CRDs and update the manifests. If yours is not updated, ensure that the path to its API is included in our calls to the Makefile targets.

To add this generator to another repo:

1. Vendor github.com/openshift/build-machinery-go

2. Update your Makefile to include the following:

include $(addprefix ./vendor/github.com/openshift/build-machinery-go/make/, \
  targets/openshift/crd-schema-gen.mk \
)

$(call add-crd-gen,<TARGET_NAME>,<API_DIRECTORY>,<CRD_MANIFESTS>,<MANIFEST_OUTPUT>)

The parameters for the call are:

1. TARGET_NAME: The name of your generated Make target. This can be anything, as long as it does not conflict with another make target. Recommended to be your api name.
2. API_DIRECTORY: The location of your API. For example if your Go types are located under pkg/apis/myoperator/v1/types.go, this should be ./pkg/apis/myoperator/v1.
3. CRD_MANIFESTS: The directory your CRDs are located in. For example, if that is manifests/my_operator.crd.yaml then it should be ./manifests
4. MANIFEST_OUTPUT: This should most likely be the same as CRD_MANIFESTS, and is only provided for flexibility to output generated code to a different directory.

You can include as many calls to different APIs as necessary, or if you have multiple APIs under the same directory (eg, v1 and v2beta1) you can use 1 call to the parent directory pointing to your API.

After this, calling make update-codegen-crds should generate a new structural OpenAPIV3 schema for your CRDs.

Notes

• This will not generate entire CRDs, only their OpenAPIV3 schemas. If you do not already have a CRD, you will get no output from the generator.
• Ensure that your API is correctly declared for the generator to pick it up. That means, in your doc.go, include the following:
  1. // +groupName=<API_GROUP_NAME>, this should match the group in your CRD spec
  2. // +kubebuilder:validation:Optional, this tells the operator that fields should be optional unless explicitly marked with // +kubebuilder:validation:Required

For more information on the API markers to add to your Go types, see the Kubebuilder book

Post-schema-generation Patches

Schema generation features might be limited or fall behind what CRD schemas supports in the latest Kubernetes version. To work around this, there are two patch mechanisms implemented by the add-crd-gen target. Basic idea is that you place a patch file next to the CRD yaml manifest with either yaml-merge-patch or yaml-patch as extension, but with the same base name. The update-codegen-crds Makefile target will apply these after calling kubebuilder's controller-gen:

• yaml-merge-patch: these are applied via yq m -x <yaml-file> <patch-file> compare https://mikefarah.gitbook.io/yq/commands/merge#overwrite-values.
• yaml-patch: these are applied via yaml-patch -o <patch-file> < <yaml-file> using https://github.com/krishicks/yaml-patch.