Discover all GVKs for controller

main.go

/*
Copyright 2020 Alexander Eldeib.
*/

package main

import (
	"flag"
	"os"

	examplev1alpha1 "github.com/alexeldeib/watchall/api/v1alpha1"
	"github.com/alexeldeib/watchall/controllers"
	"github.com/sanity-io/litter"
	"k8s.io/apimachinery/pkg/runtime"
	"k8s.io/apimachinery/pkg/runtime/schema"
	"k8s.io/client-go/discovery"
	"k8s.io/client-go/discovery/cached/memory"
	clientgoscheme "k8s.io/client-go/kubernetes/scheme"
	_ "k8s.io/client-go/plugin/pkg/client/auth/gcp"
	"k8s.io/client-go/restmapper"
	ctrl "sigs.k8s.io/controller-runtime"
	"sigs.k8s.io/controller-runtime/pkg/log/zap"
	// +kubebuilder:scaffold:imports
)

var (
	scheme   = runtime.NewScheme()
	setupLog = ctrl.Log.WithName("setup")
)

func init() {
	_ = clientgoscheme.AddToScheme(scheme)

	_ = examplev1alpha1.AddToScheme(scheme)
	// +kubebuilder:scaffold:scheme
}

func main() {
	var metricsAddr string
	var enableLeaderElection bool
	flag.StringVar(&metricsAddr, "metrics-addr", ":8080", "The address the metric endpoint binds to.")
	flag.BoolVar(&enableLeaderElection, "enable-leader-election", false,
		"Enable leader election for controller manager. Enabling this will ensure there is only one active controller manager.")
	flag.Parse()

	ctrl.SetLogger(zap.New(func(o *zap.Options) {
		o.Development = true
	}))

	restconfig := ctrl.GetConfigOrDie()
	d := discovery.NewDiscoveryClientForConfigOrDie(restconfig)
	dc := memory.NewMemCacheClient(d)

	_, apiResourceList, err := dc.ServerGroupsAndResources()
	if err != nil {
		setupLog.Error(err, "failed to fetch api groups and resources")
	}

	gvrs, err := discovery.GroupVersionResources(apiResourceList)
	if err != nil {
		setupLog.Error(err, "failed to convert api resource list to gvr")
	}

	mapper := restmapper.NewDeferredDiscoveryRESTMapper(dc)

	var gvks []schema.GroupVersionKind
	for gvr := range gvrs {
		if strings.Contains(gvr.Resource, "/") {
			setupLog.Info("skipping gvr which is likely subresource", "gvr", gvr)
			continue
		}
		gvk, err := mapper.KindFor(gvr)
		if err != nil {
			setupLog.Error(err, "failed to map gvr to gvk")
		}
		gvks = append(gvks, gvk)
	}

	for i := range gvks {
		litter.Dump(gvks[i])
	}

	mgr, err := ctrl.NewManager(restconfig, ctrl.Options{
		Scheme:             scheme,
		MetricsBindAddress: metricsAddr,
		LeaderElection:     enableLeaderElection,
		Port:               9443,
	})
	if err != nil {
		setupLog.Error(err, "unable to start manager")
		os.Exit(1)
	}

	if err = (&controllers.GenericReconciler{
		Client: mgr.GetClient(),
		Log:    ctrl.Log.WithName("controllers").WithName("Generic"),
		Scheme: mgr.GetScheme(),
	}).SetupWithManager(mgr); err != nil {
		setupLog.Error(err, "unable to create controller", "controller", "Generic")
		os.Exit(1)
	}
	// +kubebuilder:scaffold:builder

	setupLog.Info("starting manager")
	if err := mgr.Start(ctrl.SetupSignalHandler()); err != nil {
		setupLog.Error(err, "problem running manager")
		os.Exit(1)
	}
}