Add retry logic for image copying (#63)

* Add retry logic for image copying

* Remove unnecessary break

* Change to 5 retries

* Use proper format for prints

* Return empty byte array

* Add todo

(cherry picked from commit b7c9bbd)

velero-plugins/migimagestream/backup.go

@@ -79,7 +79,7 @@ func (p *BackupPlugin) Execute(item runtime.Unstructured, backup *v1.Backup) (ru
 				p.Log.Info(fmt.Sprintf("[is-backup] copying from: %s", srcPath))
 				p.Log.Info(fmt.Sprintf("[is-backup] copying to: %s", destPath))
 
-				imgManifest, err := copyImageBackup(srcPath, destPath)
+				imgManifest, err := copyImageBackup(p.Log, srcPath, destPath)
 				if err != nil {
 					p.Log.Info(fmt.Sprintf("[is-backup] Error copying image: %v", err))
 					return nil, nil, err
@@ -126,7 +126,7 @@ func findStatusTag(tags []imagev1API.NamedTagEventList, name string) *imagev1API
 	return nil
 }
 
-func copyImageBackup(src, dest string) ([]byte, error) {
+func copyImageBackup(log logrus.FieldLogger, src, dest string) ([]byte, error) {
 	sourceCtx, err := internalRegistrySystemContext()
 	if err != nil {
 		return []byte{}, err
@@ -135,5 +135,5 @@ func copyImageBackup(src, dest string) ([]byte, error) {
 	if err != nil {
 		return []byte{}, err
 	}
-	return copyImage(src, dest, sourceCtx, destinationCtx)
+	return copyImage(log, src, dest, sourceCtx, destinationCtx)
 }

velero-plugins/migimagestream/restore.go

@@ -91,7 +91,7 @@ func (p *RestorePlugin) Execute(input *velero.RestoreItemActionExecuteInput) (*v
 
 				p.Log.Info(fmt.Sprintf("[is-restore] copying from: %s", srcPath))
 				p.Log.Info(fmt.Sprintf("[is-restore] copying to: %s", destPath))
-				manifest, err := copyImageRestore(srcPath, destPath)
+				manifest, err := copyImageRestore(p.Log, srcPath, destPath)
 				if err != nil {
 					p.Log.Info(fmt.Sprintf("[is-restore] Error copying image: %v", err))
 					return nil, err
@@ -108,7 +108,7 @@ func (p *RestorePlugin) Execute(input *velero.RestoreItemActionExecuteInput) (*v
 	return velero.NewRestoreItemActionExecuteOutput(input.Item).WithoutRestore(), nil
 }
 
-func copyImageRestore(src, dest string) ([]byte, error) {
+func copyImageRestore(log logrus.FieldLogger, src, dest string) ([]byte, error) {
 	sourceCtx, err := migrationRegistrySystemContext()
 	if err != nil {
 		return []byte{}, err
@@ -117,5 +117,5 @@ func copyImageRestore(src, dest string) ([]byte, error) {
 	if err != nil {
 		return []byte{}, err
 	}
-	return copyImage(src, dest, sourceCtx, destinationCtx)
+	return copyImage(log, src, dest, sourceCtx, destinationCtx)
 }

velero-plugins/migimagestream/shared.go

@@ -4,17 +4,20 @@ import (
 	"context"
 	"errors"
 	"fmt"
+	"strings"
+	"time"
 
 	"github.com/containers/image/v5/copy"
 	"github.com/containers/image/v5/signature"
 	"github.com/containers/image/v5/transports/alltransports"
 	"github.com/containers/image/v5/types"
 	imagev1API "github.com/openshift/api/image/v1"
+	"github.com/sirupsen/logrus"
 
 	"k8s.io/client-go/rest"
 )
 
-func copyImage(src, dest string, sourceCtx, destinationCtx *types.SystemContext) ([]byte, error) {
+func copyImage(log logrus.FieldLogger, src, dest string, sourceCtx, destinationCtx *types.SystemContext) ([]byte, error) {
 	policyContext, err := getPolicyContext()
 	if err != nil {
 		return []byte{}, fmt.Errorf("Error loading trust policy: %v", err)
@@ -29,11 +32,29 @@ func copyImage(src, dest string, sourceCtx, destinationCtx *types.SystemContext)
 	if err != nil {
 		return []byte{}, fmt.Errorf("Invalid destination name %s: %v", dest, err)
 	}
-	manifest, err := copy.Image(context.Background(), policyContext, destRef, srcRef, &copy.Options{
-		SourceCtx:      sourceCtx,
-		DestinationCtx: destinationCtx,
-	})
-	return manifest, err
+
+	// Let's retry the image copy up to 10 times
+	// Each retry will wait 5 seconds longer
+	// Let's log a warning if we encounter `blob unknown to registry`
+	// TODO: Change this to only retry on specific errors from image copy
+	retryWait := 5
+	log.Info(fmt.Sprintf("copying image: %s; will attempt up to 5 times...", src))
+	for i := 0; i < 4; i++ {
+		manifest, err := copy.Image(context.Background(), policyContext, destRef, srcRef, &copy.Options{
+			SourceCtx:      sourceCtx,
+			DestinationCtx: destinationCtx,
+		})
+		if err == nil {
+			return manifest, nil
+		}
+		if strings.Contains(err.Error(), "blob unknown to registry") {
+			log.Warn(fmt.Sprintf("encountered `blob unknown to registry error` for image %s", src))
+		}
+		log.Info(fmt.Sprintf("attempt #%v failed, waiting %vs and then retrying", i, retryWait))
+		time.Sleep(time.Duration(retryWait) * time.Second)
+		retryWait += 5
+	}
+	return []byte{}, err
 }
 
 func getPolicyContext() (*signature.PolicyContext, error) {