custom-kube-scheduler/kubernetes-v1.15.4/pkg/kubectl/cmd/util/factory.go

/*
Copyright 2014 The Kubernetes Authors.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

package util

import (
	"k8s.io/apimachinery/pkg/api/meta"
	"k8s.io/cli-runtime/pkg/genericclioptions"
	"k8s.io/cli-runtime/pkg/resource"
	"k8s.io/client-go/dynamic"
	"k8s.io/client-go/kubernetes"
	restclient "k8s.io/client-go/rest"
	"k8s.io/kubernetes/pkg/kubectl/cmd/util/openapi"
	"k8s.io/kubernetes/pkg/kubectl/validation"
)

// Factory provides abstractions that allow the Kubectl command to be extended across multiple types
// of resources and different API sets.
// The rings are here for a reason. In order for composers to be able to provide alternative factory implementations
// they need to provide low level pieces of *certain* functions so that when the factory calls back into itself
// it uses the custom version of the function. Rather than try to enumerate everything that someone would want to override
// we split the factory into rings, where each ring can depend on methods in an earlier ring, but cannot depend
// upon peer methods in its own ring.
// TODO: make the functions interfaces
// TODO: pass the various interfaces on the factory directly into the command constructors (so the
// commands are decoupled from the factory).
type Factory interface {
	genericclioptions.RESTClientGetter

	// DynamicClient returns a dynamic client ready for use
	DynamicClient() (dynamic.Interface, error)

	// KubernetesClientSet gives you back an external clientset
	KubernetesClientSet() (*kubernetes.Clientset, error)

	// Returns a RESTClient for accessing Kubernetes resources or an error.
	RESTClient() (*restclient.RESTClient, error)

	// NewBuilder returns an object that assists in loading objects from both disk and the server
	// and which implements the common patterns for CLI interactions with generic resources.
	NewBuilder() *resource.Builder

	// Returns a RESTClient for working with the specified RESTMapping or an error. This is intended
	// for working with arbitrary resources and is not guaranteed to point to a Kubernetes APIServer.
	ClientForMapping(mapping *meta.RESTMapping) (resource.RESTClient, error)
	// Returns a RESTClient for working with Unstructured objects.
	UnstructuredClientForMapping(mapping *meta.RESTMapping) (resource.RESTClient, error)

	// Returns a schema that can validate objects stored on disk.
	Validator(validate bool) (validation.Schema, error)
	// OpenAPISchema returns the schema openapi schema definition
	OpenAPISchema() (openapi.Resources, error)
}