base.go

package getter

import (
	"context"

	apierrors "k8s.io/apimachinery/pkg/api/errors"
	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
	"k8s.io/apimachinery/pkg/fields"
	"k8s.io/apimachinery/pkg/labels"
	"k8s.io/apimachinery/pkg/runtime/schema"
	"k8s.io/apimachinery/pkg/types"
	"sigs.k8s.io/controller-runtime/pkg/client"
	"sigs.k8s.io/yaml"
)

// GetResourceInCache gets a specific Kubernetes object in local cache, object can be any types
// which are registered by "scheme.AddToScheme()".
// Return true if object is found, false if not, or an error if something bad happened.
func GetResourceInCache(ns, name string, obj client.Object, cl client.Reader) (bool, error) {
	err := cl.Get(context.TODO(), types.NamespacedName{Namespace: ns, Name: name}, obj)
	if err != nil {
		if apierrors.IsNotFound(err) {
			return false, nil
		}
		return false, err
	}

	return true, nil
}

// ListResourceInCache gets a set of specific Kubernetes object in local cache, object can be any types
// which are registered by "scheme.AddToScheme()".
// Important: fieldSelector must be nil or contain just one kv pair, otherwise, controller-runtime will return error.
func ListResourceInCache(ns string, selector labels.Selector, fieldSelector fields.Selector, obj client.ObjectList, cl client.Reader) error {
	opts := []client.ListOption{client.InNamespace(ns)}
	if selector != nil && !selector.Empty() {
		opts = append(opts, client.MatchingLabelsSelector{Selector: selector})
	}

	if fieldSelector != nil && !fieldSelector.Empty() {
		opts = append(opts, client.MatchingFieldsSelector{Selector: fieldSelector})
	}

	return cl.List(context.TODO(), obj, opts...)
}

// ListUnstructuredResourceInCache gets a set of specific Kubernetes object in local cache, and return a representation in yaml format.
func ListUnstructuredResourceInCache(ns string, selector labels.Selector, fieldSelector fields.Selector, gvk schema.GroupVersionKind, cl client.Reader) ([]*unstructured.Unstructured, error) {
	u := &unstructured.UnstructuredList{}
	u.SetGroupVersionKind(gvk)
	err := ListResourceInCache(ns, selector, fieldSelector, u, cl)
	if err != nil {
		return nil, err
	}

	var res []*unstructured.Unstructured
	for i := range u.Items {
		res = append(res, &u.Items[i])
	}
	return res, err
}

// GetResourceJSONInCache gets a specific Kubernetes object in local cache, and return a representation in json format.
// Return true if object is found, false if not, or an error if something bad happened.
func GetResourceJSONInCache(ns, name string, gvk schema.GroupVersionKind, cl client.Reader) ([]byte, bool, error) {
	u := &unstructured.Unstructured{}
	u.SetGroupVersionKind(gvk)

	found, err := GetResourceInCache(ns, name, u, cl)
	if err != nil || !found {
		return nil, false, err
	}

	data, err := u.MarshalJSON()
	if err != nil {
		return nil, false, err
	}

	return data, true, nil
}

// GetResourceYamlInCache gets a specific Kubernetes object in local cache, and return a representation in yaml format.
// Return true if object is found, false if not, or an error if something bad happened.
func GetResourceYamlInCache(ns, name string, gvk schema.GroupVersionKind, cl client.Reader) ([]byte, bool, error) {
	d, found, err := GetResourceJSONInCache(ns, name, gvk, cl)
	if err != nil || !found || len(d) == 0 {
		return nil, false, err
	}

	data, err := yaml.JSONToYAML(d)
	if err != nil {
		return nil, false, err
	}

	return data, true, nil
}

// ListResourceJSONInCache gets a set of specific Kubernetes object in local cache, and return a representation in json format.
func ListResourceJSONInCache(ns string, selector labels.Selector, fieldSelector fields.Selector, gvk schema.GroupVersionKind, cl client.Reader) ([][]byte, error) {
	u := &unstructured.UnstructuredList{}
	u.SetGroupVersionKind(gvk)

	err := ListResourceInCache(ns, selector, fieldSelector, u, cl)
	if err != nil {
		return nil, err
	}

	var res [][]byte
	for _, item := range u.Items {
		data, err := item.MarshalJSON()
		if err != nil {
			return nil, err
		}
		res = append(res, data)
	}

	return res, nil
}

// ListResourceYamlInCache gets a set of specific Kubernetes object in local cache, and return a representation in yaml format.
func ListResourceYamlInCache(ns string, selector labels.Selector, fieldSelector fields.Selector, gvk schema.GroupVersionKind, cl client.Reader) ([][]byte, error) {
	u := &unstructured.UnstructuredList{}
	u.SetGroupVersionKind(gvk)

	err := ListResourceInCache(ns, selector, fieldSelector, u, cl)
	if err != nil {
		return nil, err
	}

	var res [][]byte
	for _, item := range u.Items {
		item.SetManagedFields(nil)
		data, err := item.MarshalJSON()
		if err != nil {
			return nil, err
		}
		data, err = yaml.JSONToYAML(data)
		if err != nil {
			return nil, err
		}
		res = append(res, data)
	}

	return res, nil
}