cache.go

package main

import (
	"context"
	"errors"
	"fmt"

	corev1 "k8s.io/api/core/v1"
	rbacv1 "k8s.io/api/rbac/v1"
	"k8s.io/apimachinery/pkg/runtime"
	"k8s.io/client-go/rest"
	"sigs.k8s.io/controller-runtime/pkg/cache"
	"sigs.k8s.io/controller-runtime/pkg/client"
)

func BuildAndStartCache(ctx context.Context, cfg *rest.Config) (cache.Cache, error) {
	s := runtime.NewScheme()
	if err := corev1.AddToScheme(s); err != nil {
		return nil, err
	}
	if err := rbacv1.AddToScheme(s); err != nil {
		return nil, err
	}
	oo := []client.Object{
		&corev1.Namespace{},
		&rbacv1.RoleBinding{},
		&rbacv1.ClusterRole{},
		&rbacv1.ClusterRoleBinding{},
		&rbacv1.Role{},
	}
	c, err := cache.New(cfg, cache.Options{
		Scheme: s,
		ByObject: map[client.Object]cache.ByObject{
			&corev1.Namespace{}:          {},
			&rbacv1.RoleBinding{}:        {},
			&rbacv1.ClusterRole{}:        {},
			&rbacv1.ClusterRoleBinding{}: {},
			&rbacv1.Role{}:               {},
		},
	})
	if err != nil {
		return nil, err
	}

	for _, o := range oo {
		_, err := c.GetInformer(ctx, o)
		if err != nil {
			return nil, fmt.Errorf("error starting cache: getting informer for %s: %w", o.GetObjectKind().GroupVersionKind().String(), err)
		}
	}

	go func() {
		if err := c.Start(ctx); err != nil {
			panic(err)
		}
	}()
	if !c.WaitForCacheSync(ctx) {
		return nil, errors.New("error starting the cache")
	}

	return c, nil
}