backup: Use meta/v1.Time instead of time.Time

After I generated the code based on k8s object
(zz_generated.deepcopy.go), we happened to be in failing to build.
This is because all k8s custom resource's fileds should implement
DeepCopyInto but time.Time we added doesn't implement it.
For this purpose we should have used meta/v1.Time which is the
implementation to implement all necessary function for k8s object
and same function of time.Time.

And also this commit include some refactoring which is pointed out
in code-review

pkg/apis/etcd/v1beta2/backup_types.go

@@ -15,8 +15,6 @@
 package v1beta2
 
 import (
-	"time"
-
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 )
 
@@ -117,7 +115,7 @@ type BackupStatus struct {
 	// EtcdRevision is the revision of etcd's KV store where the backup is performed on.
 	EtcdRevision int64 `json:"etcdRevision,omitempty"`
 	// LastSuccessDate indicate the time to get snapshot last time
-	LastSuccessDate time.Time `json:"lastSuccessDate,omitempty"`
+	LastSuccessDate metav1.Time `json:"lastSuccessDate,omitempty"`
 }
 
 // S3BackupSource provides the spec how to store backups on S3.

pkg/backup/backup_manager.go

@@ -26,6 +26,7 @@ import (
 
 	"github.com/coreos/etcd/clientv3"
 	"github.com/sirupsen/logrus"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/client-go/kubernetes"
 )
 
@@ -53,31 +54,32 @@ func NewBackupManagerFromWriter(kubecli kubernetes.Interface, bw writer.Writer,
 
 // SaveSnap uses backup writer to save etcd snapshot to a specified S3 path
 // and returns backup etcd server's kv store revision and its version.
-func (bm *BackupManager) SaveSnap(ctx context.Context, s3Path string, now time.Time, isPeriodic bool) (int64, string, error) {
+func (bm *BackupManager) SaveSnap(ctx context.Context, s3Path string, isPeriodic bool) (int64, string, *metav1.Time, error) {
+	now := time.Now().UTC()
 	etcdcli, rev, err := bm.etcdClientWithMaxRevision(ctx)
 	if err != nil {
-		return 0, "", fmt.Errorf("create etcd client failed: %v", err)
+		return 0, "", nil, fmt.Errorf("create etcd client failed: %v", err)
 	}
 	defer etcdcli.Close()
 
 	resp, err := etcdcli.Status(ctx, etcdcli.Endpoints()[0])
 	if err != nil {
-		return 0, "", fmt.Errorf("failed to retrieve etcd version from the status call: %v", err)
+		return 0, "", nil, fmt.Errorf("failed to retrieve etcd version from the status call: %v", err)
 	}
 
 	rc, err := etcdcli.Snapshot(ctx)
 	if err != nil {
-		return 0, "", fmt.Errorf("failed to receive snapshot (%v)", err)
+		return 0, "", nil, fmt.Errorf("failed to receive snapshot (%v)", err)
 	}
 	defer rc.Close()
 	if isPeriodic {
 		s3Path = fmt.Sprintf(s3Path+"_v%d_%s", rev, now.Format("2006-01-02-15:04:05"))
 	}
 	_, err = bm.bw.Write(ctx, s3Path, rc)
 	if err != nil {
-		return 0, "", fmt.Errorf("failed to write snapshot (%v)", err)
+		return 0, "", nil, fmt.Errorf("failed to write snapshot (%v)", err)
 	}
-	return rev, resp.Version, nil
+	return rev, resp.Version, &metav1.Time{now}, nil
 }
 
 // EnsureMaxBackup to ensure the number of snapshot is under maxcount

pkg/controller/backup-operator/abs_backup.go

@@ -18,7 +18,6 @@ import (
 	"context"
 	"crypto/tls"
 	"fmt"
-	"time"
 
 	api "github.com/coreos/etcd-operator/pkg/apis/etcd/v1beta2"
 	"github.com/coreos/etcd-operator/pkg/backup"
@@ -41,18 +40,17 @@ func handleABS(ctx context.Context, kubecli kubernetes.Interface, s *api.ABSBack
 	if tlsConfig, err = generateTLSConfig(kubecli, clientTLSSecret, namespace); err != nil {
 		return nil, err
 	}
-	now := time.Now().UTC()
 	bm := backup.NewBackupManagerFromWriter(kubecli, writer.NewABSWriter(cli.ABS), tlsConfig, endpoints, namespace)
 
-	rev, etcdVersion, err := bm.SaveSnap(ctx, s.Path, now, isPeriodic)
+	rev, etcdVersion, now, err := bm.SaveSnap(ctx, s.Path, isPeriodic)
 	if err != nil {
 		return nil, fmt.Errorf("failed to save snapshot (%v)", err)
 	}
 	if maxBackup > 0 {
-		err := bm.EnsureMaxbackup(ctx, s.Path, maxBackup)
+		err := bm.EnsureMaxBackup(ctx, s.Path, maxBackup)
 		if err != nil {
 			return nil, fmt.Errorf("succeeded in saving snapshot but failed to delete old snapshot (%v)", err)
 		}
 	}
-	return &api.BackupStatus{EtcdVersion: etcdVersion, EtcdRevision: rev, LastSuccessDate: now}, nil
+	return &api.BackupStatus{EtcdVersion: etcdVersion, EtcdRevision: rev, LastSuccessDate: *now}, nil
 }

pkg/controller/backup-operator/gcs_backup.go

@@ -18,7 +18,6 @@ import (
 	"context"
 	"crypto/tls"
 	"fmt"
-	"time"
 
 	api "github.com/coreos/etcd-operator/pkg/apis/etcd/v1beta2"
 	"github.com/coreos/etcd-operator/pkg/backup"
@@ -42,18 +41,17 @@ func handleGCS(ctx context.Context, kubecli kubernetes.Interface, s *api.GCSBack
 	if tlsConfig, err = generateTLSConfig(kubecli, clientTLSSecret, namespace); err != nil {
 		return nil, err
 	}
-	now := time.Now().UTC()
 	bm := backup.NewBackupManagerFromWriter(kubecli, writer.NewGCSWriter(cli.GCS), tlsConfig, endpoints, namespace)
 
-	rev, etcdVersion, err := bm.SaveSnap(ctx, s.Path, now, isPeriodic)
+	rev, etcdVersion, now, err := bm.SaveSnap(ctx, s.Path, isPeriodic)
 	if err != nil {
 		return nil, fmt.Errorf("failed to save snapshot (%v)", err)
 	}
 	if maxBackup > 0 {
-		err := bm.EnsureMaxbackup(ctx, s.Path, maxBackup)
+		err := bm.EnsureMaxBackup(ctx, s.Path, maxBackup)
 		if err != nil {
 			return nil, fmt.Errorf("succeeded in saving snapshot but failed to delete old snapshot (%v)", err)
 		}
 	}
-	return &api.BackupStatus{EtcdVersion: etcdVersion, EtcdRevision: rev, LastSuccessDate: now}, nil
+	return &api.BackupStatus{EtcdVersion: etcdVersion, EtcdRevision: rev, LastSuccessDate: *now}, nil
 }

pkg/controller/backup-operator/s3_backup.go

@@ -18,7 +18,6 @@ import (
 	"context"
 	"crypto/tls"
 	"fmt"
-	"time"
 
 	api "github.com/coreos/etcd-operator/pkg/apis/etcd/v1beta2"
 	"github.com/coreos/etcd-operator/pkg/backup"
@@ -43,18 +42,17 @@ func handleS3(ctx context.Context, kubecli kubernetes.Interface, s *api.S3Backup
 	if tlsConfig, err = generateTLSConfig(kubecli, clientTLSSecret, namespace); err != nil {
 		return nil, err
 	}
-	now := time.Now().UTC()
 	bm := backup.NewBackupManagerFromWriter(kubecli, writer.NewS3Writer(cli.S3), tlsConfig, endpoints, namespace)
 
-	rev, etcdVersion, err := bm.SaveSnap(ctx, s.Path, now, isPeriodic)
+	rev, etcdVersion, now, err := bm.SaveSnap(ctx, s.Path, isPeriodic)
 	if err != nil {
 		return nil, fmt.Errorf("failed to save snapshot (%v)", err)
 	}
 	if maxBackup > 0 {
-		err := bm.EnsureMaxbackup(ctx, s.Path, maxBackup)
+		err := bm.EnsureMaxBackup(ctx, s.Path, maxBackup)
 		if err != nil {
 			return nil, fmt.Errorf("succeeded in saving snapshot but failed to delete old snapshot (%v)", err)
 		}
 	}
-	return &api.BackupStatus{EtcdVersion: etcdVersion, EtcdRevision: rev, LastSuccessDate: now}, nil
+	return &api.BackupStatus{EtcdVersion: etcdVersion, EtcdRevision: rev, LastSuccessDate: *now}, nil
 }

pkg/controller/backup-operator/sync.go

@@ -75,10 +75,7 @@ func (b *Backup) processItem(key string) error {
 	if eb.DeletionTimestamp != nil {
 		b.deletePeriodicBackupRunner(eb.ObjectMeta.UID)
 		err := b.removeFinalizerOfPeriodicBackup(eb)
-		if err != nil {
-			return err
-		}
-		return nil
+		return err
 	}
 	isPeriodic := isPeriodicBackup(&eb.Spec)
 
@@ -168,10 +165,7 @@ func (b *Backup) removeFinalizerOfPeriodicBackup(eb *api.EtcdBackup) error {
 	}
 	metadata.SetFinalizers(finalizers)
 	_, err = b.backupCRCli.EtcdV1beta2().EtcdBackups(b.namespace).Update(ebNew.(*api.EtcdBackup))
-	if err != nil {
-		return err
-	}
-	return nil
+	return err
 }
 
 func (b *Backup) periodicRunnerFunc(ctx context.Context, t *time.Ticker, eb *api.EtcdBackup) {