The Daily Parker

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Upgrading to Azure Storage Client 2.0

Oh, Azure Storage team, why did you break everything?

I love upgrades. I really do. So when Microsoft released the new version of the Windows Azure SDK (October 2012, v1.8) along with a full upgrade of the Storage Client (to 2.0), I found a little side project to upgrade, and went straight to the NuGet Package Manager for my prize.

I should say that part of my interest came from wanting to use some of the .NET 4.5 features, including the asynchronous helper methods, HTML 5, and native support for SQL 2012 spatial types, in the new version of Weather Now that I hope to complete before year's end. The Azure SDK 1.8 supports .NET 4.5; previous version didn’t. And the Azure SDK 1.8 includes a new version of the Azure Emulator which supports 4.5 as well.

To support the new, Azure-based version (and to support a bunch of other projects that I migrated to Azure), I have a class library of façades supporting Azure. Fortunately, this architecture encapsulated all of my Azure Storage calls. Unfortunately, the upgrade broke every other line of code in the library.

0. Many have the namespaces have changed. But of course, you use ReSharper, which makes the problem go away.

1.The CloudStorageAccount.FromConfigurationSetting() method is gone. Instead, you have to use CloudStorageAccount.Parse(). Here is a the delta from TortoiseHg:

- _cloudStorageAccount = CloudStorageAccount.FromConfigurationSetting(storageSettingName);
+ var setting = CloudConfigurationManager.GetSetting(storageSettingName);
+ _cloudStorageAccount = CloudStorageAccount.Parse(setting);

2. BlobContainer.GetBlobReference() is gone, too. Instead of getting a generic IBlobContainer reference back, you have to specify whether you want a page blob or a block blob. In this app, I only use page blobs, so the delta looks like this:

- var blob = _blobContainer.GetBlobReference(blobName);
+ var blob = _blobContainer.GetBlockBlobReference(blobName);

Note that BlobContainer also has a GetPageBlobReference() method. It also has a nearly-useless GetBlobReferenceFromServer method that throws a 404 error if the blob doesn’t exist, which makes it useless for creating new blobs.

3. Blob.DeleteIfExists() works somewhat differently, too:

- var blob = _blobContainer.GetBlobReference(blobName);
- blob.DeleteIfExists(new BlobRequestOptions 
-	{ DeleteSnapshotsOption = DeleteSnapshotsOption.IncludeSnapshots });
+ var blob = _blobContainer.GetBlockBlobReference(blobName);
+ blob.DeleteIfExists();

4. Remember downloading text directly from a blob using Blob.DownloadText()? Yeah, that’s gone too. Blobs are all about streams now:

- var blob = _blobContainer.GetBlobReference(blobName);
- return blob.DownloadText();
+ using (var stream = new MemoryStream())
+ {
+ 	var blob = _blobContainer.GetBlockBlobReference(blobName);
+ 	blob.DownloadToStream(stream);
+ 	using (var reader = new StreamReader(stream, true))
+ 	{
+ 		stream.Position = 0;
+ 		return reader.ReadToEnd();
+ 	}
+ }

5. Because blobs are all stream-based now, you can’t simply upload files to them. Here’s the correction to the disappearance of Blob.UploadFile():

- var blob = _blobContainer.GetBlobReference(blobName);
- blob.UploadByteArray(value);
+ var blob = _blobContainer.GetBlockBlobReference(blobName);
+ using (var stream = new MemoryStream(value))
+ {
+ 	blob.UploadFromStream(stream);
+ }

6. Microsoft even helpfully corrected a spelling error which, yes, broke my code:

- _blobContainer.CreateIfNotExist();
+ _blobContainer.CreateIfNotExists();

Yes, if not existS. Notice the big red S, which is something I’d like to give the Azure team after this upgrade.*

7. We’re not done, yet. They fixed a "problem" with tables, too:

  var cloudTableClient = _cloudStorageAccount.CreateCloudTableClient();
- cloudTableClient.CreateTableIfNotExist(TableName);
- var context = cloudTableClient.GetDataServiceContext();
+ var table = cloudTableClient.GetTableReference(TableName);
+ table.CreateIfNotExists();
+ var context = cloudTableClient.GetTableServiceContext();

8. Finally, if you have used the CloudStorageAccount.SetConfigurationSettingPublisher() method, that’s gone too, but you don’t need it. Instead, use the CloudConfigurationManager.GetSetting() method directly. Instead of doing this:

if (RoleEnvironment.IsAvailable)
		(configName, configSetter) => 
		(configName, configSetter) => 

You can simply do this:

var someSetting = CloudConfigurationManager.GetSetting(settingKey);

The CloudConfiguration.GetSetting() method first tries to get the setting from Azure, then from the ConfigurationManager (i.e., local settings).

I hope I have just saved you three hours of silently cursing Microsoft’s Azure Storage team.

* Apologies to Bill Cosby.

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