Azure Storage Blob Rename

Question

UPDATE:

I updated the code after @IsaacAbrahams comments and @Viggity's answer, this version should prevent you from having to load everything into a MemoryStream, and waits until the copy is completed before deleting the source blob.

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For anyone getting late to the party but stumbling on this post using Azure Storage API V2, here's an extension method to do it quick and dirty (+ async version):

public static class BlobContainerExtensions 
{
   public static void Rename(this CloudBlobContainer container, string oldName, string newName)
   {
      //Warning: this Wait() is bad practice and can cause deadlock issues when used from ASP.NET applications
      RenameAsync(container, oldName, newName).Wait();
   }

   public static async Task RenameAsync(this CloudBlobContainer container, string oldName, string newName)
   {
      var source = await container.GetBlobReferenceFromServerAsync(oldName);
      var target = container.GetBlockBlobReference(newName);

      await target.StartCopyFromBlobAsync(source.Uri);

      while (target.CopyState.Status == CopyStatus.Pending)
            await Task.Delay(100);

      if (target.CopyState.Status != CopyStatus.Success)
          throw new Exception("Rename failed: " + target.CopyState.Status);

      await source.DeleteAsync();
    }
}

Update for Azure Storage 7.0

    public static async Task RenameAsync(this CloudBlobContainer container, string oldName, string newName)
    {
        CloudBlockBlob source =(CloudBlockBlob)await container.GetBlobReferenceFromServerAsync(oldName);
        CloudBlockBlob target = container.GetBlockBlobReference(newName);


        await target.StartCopyAsync(source);

        while (target.CopyState.Status == CopyStatus.Pending)
            await Task.Delay(100);

        if (target.CopyState.Status != CopyStatus.Success)
            throw new Exception("Rename failed: " + target.CopyState.Status);

        await source.DeleteAsync();            
    }

Disclaimer: This is a quick and dirty method to make the rename execute in a synchronous way. It fits my purposes, however as other users noted, copying can take a long time (up to days), so the best way is NOT to perform this in 1 method like this answer but instead:

• Start the copy process
• Poll the status of the copy operation
• Delete the original blob when the copy is completed.

There is practical way to do so, although Azure Blob Service API does not directly support ability to rename or move blobs.

You can, however, copy and then delete.

I originally used code from @Zidad, and in low load circumstances it usually worked (I'm almost always renaming small files, ~10kb).

DO NOT StartCopyFromBlob then Delete!!!!!!!!!!!!!!

In a high load scenario, I LOST ~20% of the files I was renaming (thousands of files). As mentioned in the comments on his answer, StartCopyFromBlob just starts the copy. There is no way for you to wait for the copy to finish.

The only way for you to guarantee the copy finishes is to download it and re-upload. Here is my updated code:

public void Rename(string containerName, string oldFilename, string newFilename)
{
    var oldBlob = GetBlobReference(containerName, oldFilename);
    var newBlob = GetBlobReference(containerName, newFilename);

    using (var stream = new MemoryStream())
    {
        oldBlob.DownloadToStream(stream);
        stream.Seek(0, SeekOrigin.Begin);
        newBlob.UploadFromStream(stream);

        //copy metadata here if you need it too

        oldBlob.Delete();
    }
}