Azure Blob Storage Retention Error When Deleting Generation

Issue Description

When deleting a generation during retention checking, I've encountered a Azure API error. It looks like you're looping over the blob's but not deleting the ones that mimic a directory last, after deleting the files first.

litestream/abs/replica_client.go

Lines 145 to 153 in 5be467a

    
           for _, item := range resp.Segment.BlobItems { 
        
           	internal.OperationTotalCounterVec.WithLabelValues(ReplicaClientType, "DELETE").Inc() 
        
           	blobURL := c.containerURL.NewBlobURL(item.Name) 
        
           	if _, err := blobURL.Delete(ctx, azblob.DeleteSnapshotsOptionNone, azblob.BlobAccessConditions{}); isNotExists(err) { 
        
           		continue 
        
           	} else if err != nil { 
        
           		return err 
        
           	}

I might be missing something so please let me know if this is a config error on my end.

Relevant Error Logs

time=2024-05-08T23:52:33.957Z level=ERROR msg="retainer error" db=/var/data/some.db replica=abs error="delete generation: -> github.com/Azure/azure-storage-blob-go/azblob.newStorageError, /go/pkg/mod/github.com/!azure/azure-storage-blob-go@v0.15.0/azblob/zc_storage_error.go:42\n===== RESPONSE ERROR (ServiceCode=DirectoryIsNotEmpty)

	for _, item := range resp.Segment.BlobItems {
	internal.OperationTotalCounterVec.WithLabelValues(ReplicaClientType, "DELETE").Inc()

	blobURL := c.containerURL.NewBlobURL(item.Name)
	if _, err := blobURL.Delete(ctx, azblob.DeleteSnapshotsOptionNone, azblob.BlobAccessConditions{}); isNotExists(err) {
	continue
	} else if err != nil {
	return err
	}