registry/storage/driver/azure: fix Move method

Something seems broken on azure/azure sdk side - it is currently not
possible to copy a blob of type AppendBlob using `CopyFromURL`.
Using the AppendBlob client via NewAppendBlobClient does not work
either.

According to Azure the correct way to do this is by using
StartCopyFromURL. Because this is an async operation, we need to do
polling ourselves. A simple backoff mechanism is used, where during each
iteration, the configured delay is multiplied by the retry number.

Also introduces two new config options for the Azure driver:
copy_status_poll_max_retry, and copy_status_poll_delay.

Signed-off-by: Flavian Missi <fmissi@redhat.com>

registry/storage/driver/azure/azure.go

@@ -21,16 +21,17 @@ import (
 	"github.com/Azure/azure-sdk-for-go/sdk/storage/azblob/container"
 )
 
-const driverName = "azure"
-
 const (
+	driverName   = "azure"
 	maxChunkSize = 4 * 1024 * 1024
 )
 
 type driver struct {
-	azClient      *azureClient
-	client        *container.Client
-	rootDirectory string
+	azClient               *azureClient
+	client                 *container.Client
+	rootDirectory          string
+	copyStatusPollMaxRetry int
+	copyStatusPollDelay    time.Duration
 }
 
 type baseEmbed struct{ base.Base }
@@ -59,11 +60,19 @@ func New(params *Parameters) (*Driver, error) {
 	if err != nil {
 		return nil, err
 	}
+
+	copyStatusPollDelay, err := time.ParseDuration(params.CopyStatusPollDelay)
+	if err != nil {
+		return nil, err
+	}
+
 	client := azClient.ContainerClient()
 	d := &driver{
-		azClient:      azClient,
-		client:        client,
-		rootDirectory: params.RootDirectory,
+		azClient:               azClient,
+		client:                 client,
+		rootDirectory:          params.RootDirectory,
+		copyStatusPollMaxRetry: params.CopyStatusPollMaxRetry,
+		copyStatusPollDelay:    copyStatusPollDelay,
 	}
 	return &Driver{baseEmbed: baseEmbed{Base: base.Base{StorageDriver: d}}}, nil
 }
@@ -282,7 +291,7 @@ func (d *driver) Move(ctx context.Context, sourcePath string, destPath string) e
 		return err
 	}
 	destBlobRef := d.client.NewBlockBlobClient(d.blobName(destPath))
-	_, err = destBlobRef.CopyFromURL(ctx, sourceBlobURL, nil)
+	resp, err := destBlobRef.StartCopyFromURL(ctx, sourceBlobURL, nil)
 	if err != nil {
 		if is404(err) {
 			return storagedriver.PathNotFoundError{Path: sourcePath}
@@ -290,6 +299,39 @@ func (d *driver) Move(ctx context.Context, sourcePath string, destPath string) e
 		return err
 	}
 
+	copyStatus := *resp.CopyStatus
+
+	if d.copyStatusPollMaxRetry == -1 && copyStatus == blob.CopyStatusTypePending {
+		destBlobRef.AbortCopyFromURL(ctx, *resp.CopyID, nil)
+		return nil
+	}
+
+	retryCount := 1
+	for copyStatus == blob.CopyStatusTypePending {
+		props, err := destBlobRef.GetProperties(ctx, nil)
+		if err != nil {
+			return err
+		}
+
+		if retryCount >= d.copyStatusPollMaxRetry {
+			destBlobRef.AbortCopyFromURL(ctx, *props.CopyID, nil)
+			return fmt.Errorf("max retries for copy polling reached, aborting copy")
+		}
+
+		copyStatus = *props.CopyStatus
+		if copyStatus == blob.CopyStatusTypeAborted || copyStatus == blob.CopyStatusTypeFailed {
+			if props.CopyStatusDescription != nil {
+				return fmt.Errorf("failed to move blob: %s", *props.CopyStatusDescription)
+			}
+			return fmt.Errorf("failed to move blob with copy id %s", *props.CopyID)
+		}
+
+		if copyStatus == blob.CopyStatusTypePending {
+			time.Sleep(d.copyStatusPollDelay * time.Duration(retryCount))
+		}
+		retryCount++
+	}
+
 	_, err = d.client.NewBlobClient(d.blobName(sourcePath)).Delete(ctx, nil)
 	return err
 }