C＃+ Azure存储Blob：StorageException：当前有一个挂起的复制操作

Question

I have server that getting a URL of azure blob file (SAS read only) and copy it to another blob in different Storage account. The copy command is async command ( StartCopyAsync() ).

Copy the file is only one thing that this server doing, it's doing some more. If one (or more) of the other calculation failed, it's throw exception.

When exception occurred, I doing rollback - which mean, delete the file I copied in the first stage. I doing it like this:

await backupFile.DeleteIfExistsAsync();

The problem

I getting this error code:

System.AggregateException: One or more errors occurred. (There is currently a pending copy operation.) 
---> Microsoft.WindowsAzure.Storage.StorageException: There is currently a pending copy operation.
 at Microsoft.WindowsAzure.Storage.Core.Executor.Executor.ExecuteAsyncInternal[T](RESTCommand`1 cmd, IRetryPolicy policy, OperationContext operationContext, CancellationToken token) at Microsoft.WindowsAzure.Storage.Blob.CloudBlob.DeleteIfExistsAsync(DeleteSnapshotsOption deleteSnapshotsOption, AccessCondition accessCondition, BlobRequestOptions options, OperationContext operationContext, CancellationToken cancellationToken)

I guess it because the async copy didn't finished yet...

Is this possible to solve it with async Delete command, that will take place after the Copy command done?

Any other solution will be welcome. Thanks!

Answer 1

I would suggest you try the StartAsyncCopy() overload that accepts a CancellationToken . Once you use that overload, you should be able to cancel the copy operation through the CancellationTokenSource of the CancellationToken you used when you called the method.

See CloudBlockBlob.StartCopyAsync Method for all available overloads. And you can also take a look at CancellationTokenSource Class on how to use the cancellation mechanism.

Update

As mentioned in the comment below, you should also take a look at CloudBlob.AbortCopyAsync() in case the operation already started.

Hope it helps!