pkg/backup: use context to controll SaveSnap()

pkg/backup/backup_manager.go

@@ -20,7 +20,6 @@ import (
 	"fmt"
 
 	"github.com/coreos/etcd-operator/pkg/backup/writer"
-	"github.com/coreos/etcd-operator/pkg/util/constants"
 
 	"github.com/coreos/etcd/clientv3"
 	"github.com/sirupsen/logrus"
@@ -51,22 +50,18 @@ 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(s3Path string) (int64, string, error) {
-	etcdcli, rev, err := bm.etcdClientWithMaxRevision()
+func (bm *BackupManager) SaveSnap(ctx context.Context, s3Path string) (int64, string, error) {
+	etcdcli, rev, err := bm.etcdClientWithMaxRevision(ctx)
 	if err != nil {
 		return 0, "", fmt.Errorf("create etcd client failed: %v", err)
 	}
 	defer etcdcli.Close()
 
-	ctx, cancel := context.WithTimeout(context.Background(), constants.DefaultRequestTimeout)
 	resp, err := etcdcli.Status(ctx, etcdcli.Endpoints()[0])
-	cancel()
 	if err != nil {
 		return 0, "", fmt.Errorf("failed to retrieve etcd version from the status call: %v", err)
 	}
 
-	ctx, cancel = context.WithTimeout(context.Background(), constants.DefaultSnapshotTimeout)
-	defer cancel() // Can't cancel() after Snapshot() because that will close the reader.
 	rc, err := etcdcli.Snapshot(ctx)
 	if err != nil {
 		return 0, "", fmt.Errorf("failed to receive snapshot (%v)", err)
@@ -82,24 +77,24 @@ func (bm *BackupManager) SaveSnap(s3Path string) (int64, string, error) {
 
 // etcdClientWithMaxRevision gets the etcd endpoint with the maximum kv store revision
 // and returns the etcd client of that member.
-func (bm *BackupManager) etcdClientWithMaxRevision() (*clientv3.Client, int64, error) {
-	etcdcli, rev, err := getClientWithMaxRev(bm.endpoints, bm.etcdTLSConfig)
+func (bm *BackupManager) etcdClientWithMaxRevision(ctx context.Context) (*clientv3.Client, int64, error) {
+	etcdcli, rev, err := getClientWithMaxRev(ctx, bm.endpoints, bm.etcdTLSConfig)
 	if err != nil {
 		return nil, 0, fmt.Errorf("failed to get etcd client with maximum kv store revision: %v", err)
 	}
 	return etcdcli, rev, nil
 }
 
-func getClientWithMaxRev(endpoints []string, tc *tls.Config) (*clientv3.Client, int64, error) {
+func getClientWithMaxRev(ctx context.Context, endpoints []string, tc *tls.Config) (*clientv3.Client, int64, error) {
 	mapEps := make(map[string]*clientv3.Client)
 	var maxClient *clientv3.Client
 	maxRev := int64(0)
 	errors := make([]string, 0)
 	for _, endpoint := range endpoints {
 		cfg := clientv3.Config{
-			Endpoints:   []string{endpoint},
-			DialTimeout: constants.DefaultDialTimeout,
-			TLS:         tc,
+			Endpoints: []string{endpoint},
+			Context:   ctx,
+			TLS:       tc,
 		}
 		etcdcli, err := clientv3.New(cfg)
 		if err != nil {
@@ -108,9 +103,7 @@ func getClientWithMaxRev(endpoints []string, tc *tls.Config) (*clientv3.Client,
 		}
 		mapEps[endpoint] = etcdcli
 
-		ctx, cancel := context.WithTimeout(context.Background(), constants.DefaultRequestTimeout)
 		resp, err := etcdcli.Get(ctx, "/", clientv3.WithSerializable())
-		cancel()
 		if err != nil {
 			errors = append(errors, fmt.Sprintf("failed to get revision from endpoint (%s)", endpoint))
 			continue