Construct the typed clients we need (#1637)

The pattern of constructing all the clients to get a
kubernetes.Interface, only to extract one or two typed clients has the
side-effect of importing a lot of packages that are otherwise
unneeded.

Avoid doing so by constructing the clients we need.

This isn't sufficient to remove all these extra dependencies (because
of the use of scheme.Scheme as default), but it is a step closer.

Author: justinsb

pkg/internal/recorder/recorder.go

@@ -24,8 +24,7 @@ import (
 	"github.com/go-logr/logr"
 	corev1 "k8s.io/api/core/v1"
 	"k8s.io/apimachinery/pkg/runtime"
-	"k8s.io/client-go/kubernetes"
-	typedcorev1 "k8s.io/client-go/kubernetes/typed/core/v1"
+	corev1client "k8s.io/client-go/kubernetes/typed/core/v1"
 	"k8s.io/client-go/rest"
 	"k8s.io/client-go/tools/record"
 )
@@ -45,7 +44,7 @@ type Provider struct {
 	scheme *runtime.Scheme
 	// logger is the logger to use when logging diagnostic event info
 	logger          logr.Logger
-	evtClient       typedcorev1.EventInterface
+	evtClient       corev1client.EventInterface
 	makeBroadcaster EventBroadcasterProducer
 
 	broadcasterOnce sync.Once
@@ -98,7 +97,7 @@ func (p *Provider) getBroadcaster() record.EventBroadcaster {
 
 	p.broadcasterOnce.Do(func() {
 		broadcaster, stop := p.makeBroadcaster()
-		broadcaster.StartRecordingToSink(&typedcorev1.EventSinkImpl{Interface: p.evtClient})
+		broadcaster.StartRecordingToSink(&corev1client.EventSinkImpl{Interface: p.evtClient})
 		broadcaster.StartEventWatcher(
 			func(e *corev1.Event) {
 				p.logger.V(1).Info(e.Type, "object", e.InvolvedObject, "reason", e.Reason, "message", e.Message)
@@ -112,12 +111,12 @@ func (p *Provider) getBroadcaster() record.EventBroadcaster {
 
 // NewProvider create a new Provider instance.
 func NewProvider(config *rest.Config, scheme *runtime.Scheme, logger logr.Logger, makeBroadcaster EventBroadcasterProducer) (*Provider, error) {
-	clientSet, err := kubernetes.NewForConfig(config)
+	corev1Client, err := corev1client.NewForConfig(config)
 	if err != nil {
-		return nil, fmt.Errorf("failed to init clientSet: %w", err)
+		return nil, fmt.Errorf("failed to init client: %w", err)
 	}
 
-	p := &Provider{scheme: scheme, logger: logger, makeBroadcaster: makeBroadcaster, evtClient: clientSet.CoreV1().Events("")}
+	p := &Provider{scheme: scheme, logger: logger, makeBroadcaster: makeBroadcaster, evtClient: corev1Client.Events("")}
 	return p, nil
 }
 

pkg/internal/recorder/recorder_test.go

@@ -34,13 +34,13 @@ var _ = Describe("recorder.Provider", func() {
 			Expect(err).NotTo(HaveOccurred())
 		})
 
-		It("should return an error if failed to init clientSet.", func() {
+		It("should return an error if failed to init client.", func() {
 			// Invalid the config
 			cfg1 := *cfg
 			cfg1.Host = "invalid host"
 			_, err := recorder.NewProvider(&cfg1, scheme.Scheme, logr.DiscardLogger{}, makeBroadcaster)
 			Expect(err).NotTo(BeNil())
-			Expect(err.Error()).To(ContainSubstring("failed to init clientSet"))
+			Expect(err.Error()).To(ContainSubstring("failed to init client"))
 		})
 	})
 	Describe("GetEventRecorder", func() {

pkg/leaderelection/leader_election.go

@@ -23,7 +23,8 @@ import (
 	"os"
 
 	"k8s.io/apimachinery/pkg/util/uuid"
-	"k8s.io/client-go/kubernetes"
+	coordinationv1client "k8s.io/client-go/kubernetes/typed/coordination/v1"
+	corev1client "k8s.io/client-go/kubernetes/typed/core/v1"
 	"k8s.io/client-go/rest"
 	"k8s.io/client-go/tools/leaderelection/resourcelock"
 	"sigs.k8s.io/controller-runtime/pkg/recorder"
@@ -84,17 +85,23 @@ func NewResourceLock(config *rest.Config, recorderProvider recorder.Provider, op
 	}
 	id = id + "_" + string(uuid.NewUUID())
 
-	// Construct client for leader election
-	client, err := kubernetes.NewForConfig(rest.AddUserAgent(config, "leader-election"))
+	// Construct clients for leader election
+	rest.AddUserAgent(config, "leader-election")
+	corev1Client, err := corev1client.NewForConfig(config)
+	if err != nil {
+		return nil, err
+	}
+
+	coordinationClient, err := coordinationv1client.NewForConfig(config)
 	if err != nil {
 		return nil, err
 	}
 
 	return resourcelock.New(options.LeaderElectionResourceLock,
 		options.LeaderElectionNamespace,
 		options.LeaderElectionID,
-		client.CoreV1(),
-		client.CoordinationV1(),
+		corev1Client,
+		coordinationClient,
 		resourcelock.ResourceLockConfig{
 			Identity:      id,
 			EventRecorder: recorderProvider.GetEventRecorderFor(id),