Derive Macro CustomResourceDefinition

#[derive(CustomResourceDefinition)]
{
    // Attributes available to this derive:
    #[custom_resource_definition]
}

This custom derive can be used on a Kubernetes custom resource spec type to generate a custom resource definition object type and related trait impls.

Example

#[derive(
    Clone, Debug, PartialEq,
    k8s_openapi_derive::CustomResourceDefinition,
    serde::Deserialize, serde::Serialize,
)]
#[custom_resource_definition(
    group = "k8s-openapi-tests-custom-resource-definition.com",
    version = "v1",
    plural = "foobars",
    generate_schema,
    namespaced,
    has_subresources = "v1",
    impl_deep_merge,
)]
struct FooBarSpec {
    prop1: String,
    prop2: Vec<bool>,
    #[serde(skip_serializing_if = "Option::is_none")]
    prop3: Option<i32>,
}

Note:

• The spec type must impl the following traits (either manually or via #[derive]): Clone, Debug, PartialEq, serde::Deserialize and serde::Serialize

• The name of the spec type must end with Spec. This suffix is trimmed to generate the name of the object type.

• The k8s_openapi crate must have been added as a dependency, since the macro expansion refers to types from it.

The custom derive then generates a FooBar type that represents a custom resource corresponding to this definition:

/// Custom resource for FooBarSpec
#[derive(Clone, Debug, Default, PartialEq)]
struct FooBar {
    metadata: k8s_openapi::apimachinery::pkg::apis::meta::v1::ObjectMeta,
    spec: Option<FooBarSpec>,
    subresources: k8s_openapi::apiextensions_apiserver::pkg::apis::apiextensions::v1::CustomResourceSubresources,
}

impl k8s_openapi::Resource for FooBar { ... }

impl k8s_openapi::ListableResource for FooBar { ... }

impl k8s_openapi::Metadata for FooBar {
    type Ty = k8s_openapi::apimachinery::pkg::apis::meta::v1::ObjectMeta;

    ...
}

impl<'de> k8s_openapi::serde::Deserialize<'de> for FooBar { ... }

impl k8s_openapi::serde::Serialize for FooBar { ... }

impl k8s_openapi::schemars::JsonSchema for FooBar { ... }

The name of this type is automatically derived from the name of the spec type by truncating the Spec suffix.

The group and version meta items of the #[custom_resource_definition] attribute of the macro are used to set the “group” and “API version” in the k8s_openapi::Resource impl respectively. The “kind” is automatically set to be the same as the resource type name, ie "FooBar" in this example. The plural meta item is used to construct the URLs of API operations for this custom resource.

The generate_schema meta item is optional. If set, the generated custom resource type will have an impl of schemars::JsonSchema from the schemars crate. The schemars feature of the k8s-openapi crate must be enabled so that the types in that crate also have their schemars::JsonSchema impls enabled. You will also need to impl schemars::JsonSchema on the Spec type itself, either manually or via #[derive(schemars::JsonSchema)].

The has_subresources meta item is optional. If set, the generated custom resource type will have a subresources field. The value of the meta item specifies which namespace the type will be used from. For example, setting has_subresources = "v1" causes the field to be of the k8s_openapi::apiextensions_apiserver::pkg::apis::apiextensions::v1::CustomResourceSubresources type.

The impl_deep_merge meta item is optional. If set, the generated custom resource type will impl the k8s_openapi::DeepMerge trait. This impl will require you to impl k8s_openapi::DeepMerge on the spec type yourself.

You would then register this custom resource definition with Kubernetes, with code like this:

use k8s_openapi::apiextensions_apiserver::pkg::apis::apiextensions::v1 as apiextensions;
use k8s_openapi::apimachinery::pkg::apis::meta::v1 as meta;

// Same as the `plurals` meta item in the `#[custom_resource_definition]` attribute
let plural = "foobars";

let custom_resource_definition_spec = apiextensions::CustomResourceDefinitionSpec {
    group: <FooBar as k8s_openapi::Resource>::GROUP.to_owned(),
    names: apiextensions::CustomResourceDefinitionNames {
        kind: <FooBar as k8s_openapi::Resource>::KIND.to_owned(),
        plural: plural.to_owned(),
        short_names: Some(vec!["fb".to_owned()]),
        singular: Some("foobar".to_owned()),
        ..Default::default()
    },
    scope: "Namespaced".to_owned(),
    version: <FooBar as k8s_openapi::Resource>::VERSION.to_owned().into(),
    ..Default::default()
};

let custom_resource_definition = apiextensions::CustomResourceDefinition {
    metadata: meta::ObjectMeta {
        name: Some(format!("{plural}.{}", <FooBar as k8s_openapi::Resource>::GROUP)),
        ..Default::default()
    },
    spec: custom_resource_definition_spec.into(),
    ..Default::default()
};

client.create(custom_resource_definition);

(You may wish to generate run your crate through cargo-expand to see the macro expansion.)

See the custom_resource_definition test in the repository for a full example of using this custom derive.