downstreamclient

type ResourceStrategy ¶

type ResourceStrategy interface {
	GetClient() client.Client

	// ObjectMetaFromUpstreamObject returns an ObjectMeta struct with Namespace and
	// Name fields populated for the downstream resource.
	ObjectMetaFromUpstreamObject(context.Context, metav1.Object) (metav1.ObjectMeta, error)
	GetDownstreamNamespaceNameForUpstreamNamespace(ctx context.Context, name string) (string, error)

	SetControllerReference(context.Context, metav1.Object, metav1.Object, ...controllerutil.OwnerReferenceOption) error
	SetOwnerReference(context.Context, metav1.Object, metav1.Object, ...controllerutil.OwnerReferenceOption) error
	DeleteAnchorForObject(ctx context.Context, owner client.Object) error
}

ResourceStrategy is an interface that is used to reduce the burden of writing controllers that need to write to downstream resources that are artifacts of upstream resources and may need to be placed in downstream clusters.

One implementation could just return the client from the cluster that was passed in. Another could return a client that ends up rewriting namespaces in a way that you can target a single API server and not have conflicts. Another could return a client that aligns each source cluster with a target cluster, which could be a whole API server, or something like a KCP workspace, and doesn't do any namespace/name rewriting.

This way, the controller can be written as if it's putting resources into the same namespace as the upstream resource, but that doesn't mean it'll land in the same place as that resource.

func NewMappedNamespaceResourceStrategy(
	upstreamClusterName string,
	upstreamClient client.Client,
	downstreamClient client.Client,
) ResourceStrategy