Testing development using Azure Storage Emulator

Question

I am using Azure Storage Emulator version to test an asp.net core 2.1-rc1 web application on windows 10-x64 and WindowsAzure.Storage 9.1.1.

I have followed this guide to setup the Azure storage emulator.

https://learn.microsoft.com/en-us/azure/storage/common/storage-use-emulator

When I try to create the blob container I get this exception:

Microsoft.WindowsAzure.Storage.StorageException: Server failed to authenticate the request. Make sure the value of Authorization header is formed correctly including the signature.
at Microsoft.WindowsAzure.Storage.Core.Executor.Executor.ExecuteAsyncInternal[T](RESTCommand`1 cmd, IRetryPolicy policy, OperationContext operationContext, CancellationToken token) in C:\Program Files (x86)\Jenkins\workspace\release_dotnet_master\Lib\WindowsRuntime\Core\Executor\Executor.cs:line 316
at Microsoft.WindowsAzure.Storage.Blob.CloudBlobContainer.CreateIfNotExistsAsync(BlobContainerPublicAccessType accessType, BlobRequestOptions options, OperationContext operationContext, CancellationToken cancellationToken) in C:\Program Files (x86)\Jenkins\workspace\release_dotnet_master\Lib\WindowsRuntime\Blob\CloudBlobContainer.cs:line 165

Request Information
RequestID:c4a44dcc-301e-002e-5ad0-f2637a000000
RequestDate:Wed, 23 May 2018 22:02:36 GMT
StatusMessage:Server failed to authenticate the request. Make sure the value of Authorization header is formed correctly including the signature.
ErrorCode:AuthenticationFailed
ErrorMessage:Server failed to authenticate the request. Make sure the value of Authorization header is formed correctly including the signature.
RequestId:c4a44dcc-301e-002e-5ad0-f2637a000000
Time:2018-05-23T20:02:36.9987818Z

And I have found this in the exception additional information:-

"The MAC signature found in the HTTP request 'NeZGAEspShTRdpc/zFH++pS9YChlOczzEg0vcVGXF10=' is not the same as any computed signature. Server used following string to sign: 'PUT\n\n\n\n\n\n\n\n\n\n\n\nx-ms-client-request-id:e4b5b43c-ba27-45b1-8545-19db1c16a160\nx-ms-date:Wed, 23 May 2018 19:10:31 GMT\nx-ms-version:2017-07-29\n/devstoreaccount1/admins\nrestype:container'."

Here is my code:-

public static async Task InitializeContainersAsync()
{
    try
    {
        //Use the emulator default credenitals
        var credentials = new StorageCredentials("devstoreaccount1", "Eby8vdM02xNOcqFlqUwJPLlmEtlCDXJ1OUzFT50uSRZ6IFsuFq2UVErCz4I6tq/K1SZFPTOtr/KBHBeksoGMGw==");
        CloudStorageAccount storageAccount = new CloudStorageAccount(credentials, false);

        CloudBlobClient blobClient = storageAccount.CreateCloudBlobClient();

        CloudBlobContainer container = blobClient.GetContainerReference("testing_container");

        await container.CreateIfNotExistsAsync();
    }
    catch (StorageException ex)
    {
        Console.WriteLine(ex);
    }
}

Answer 1

If you want to use the Storage Emulator there's actually two options.

1. The simplest one is to use the connectionstring UseDevelopmentStorage=true.

The easiest way to connect to the storage emulator from your application is to configure a connection string in your application's configuration file that references the shortcut UseDevelopmentStorage=true. Here's an example of a connection string to the storage emulator in an app.config file:

<appSettings>
  <add key="StorageConnectionString" value="UseDevelopmentStorage=true" />
</appSettings>

2. If you want to build the connectionstring yourself, you also need to specify the endpoints for services you want to connect to. Taken from the article you linked to:

To create a connection string that references the emulator account name and key, you must specify the endpoints for each of the services you wish to use from the emulator in the connection string. This is necessary so that the connection string will reference the emulator endpoints, which are different than those for a production storage account. For example, the value of your connection string will look like this:

DefaultEndpointsProtocol=http;AccountName=devstoreaccount1;
AccountKey=Eby8vdM02xNOcqFlqUwJPLlmEtlCDXJ1OUzFT50uSRZ6IFsuFq2UVErCz4I6tq/K1SZFPTOtr/KBHBeksoGMGw==;
BlobEndpoint=http://127.0.0.1:10000/devstoreaccount1;
TableEndpoint=http://127.0.0.1:10002/devstoreaccount1;
QueueEndpoint=http://127.0.0.1:10001/devstoreaccount1;