In Azure Cosmos DB Table API, Creating CloudTableClient using SAS token throws error when try to check if table exist, throws exception: Value cannot be null. (Parameter 'authKeyOrResourceToken | secureAuthKey')'

Question

Hi Community,

I am recently trying to make the cosmos table access more secure using SAS token. I have existing implementation to access table using CloudTableClient, and I observed CloudTableClient can be created using SAS token, thus I gave it a try but I am stuck due to an issue discussed here.
Following are the steps I have followed:

1. First, I am creating CloudTableClient :

StorageCredentials credentials = new StorageCredentials(
            cosmosTableSettings.Uri.Host.Split('.').First(),
            accountKey.ToOriginalString());

var cosmosTableClient = new CloudTableClient(cosmosTableSettings.Uri, credentials);

2. I get the SAS token

var tableRef = cosmosTableClient.GetTableReference(tableName);
SharedAccessTablePolicy policy = new SharedAccessTablePolicy()
{
    SharedAccessExpiryTime = DateTime.UtcNow.AddHours(1),
    Permissions = SharedAccessTablePermissions.Add
    | SharedAccessTablePermissions.Query
    | SharedAccessTablePermissions.Update
    | SharedAccessTablePermissions.Delete
};
string sasToken = tableRef.GetSharedAccessSignature(policy);

3. I created CloudTableClient from sas token

credentials = new StorageCredentials(sasToken);
cosmosTableClient = new CloudTableClient(cosmosTableSettings.Uri, credentials);

1. Finally I am trying to check if table exist(or any other operation) from this new client:

var cosmosTable = this.Client.GetTableReference(tableName);
var options = new TableRequestOptions()
{
    // For the sake of consistency, we handle the retry logic with a
    // custom more robust retry policy whose data type matches across the data store
    // implementations.
    RetryPolicy = new Microsoft.Azure.Cosmos.Table.NoRetry()
};
await cosmosTable.ExistsAsync(options, new OperationContext(), cancellationToken).ConfigureAwait(false)

But in the last step I am getting the following error:

{"Value cannot be null. (Parameter 'authKeyOrResourceToken | secureAuthKey')"}

Stack Trace is :

at Microsoft.Azure.Cosmos.Table.Extensions.TableExtensionOperationHelper.<ExecuteOperationAsync>d__0`1.MoveNext()
   at Microsoft.Azure.Cosmos.Table.Extensions.TableExtensionRetryPolicy.<ExecuteUnderRetryPolicy>d__2`1.MoveNext()
   at Microsoft.Azure.Cosmos.Table.CloudTable.<ExistsAsync>d__85.MoveNext()

Please do let me know if SAS token is supported with CloudTableClient/CloudTable or am I missing something else ?

Answer 1

Hi @Prashant Patel ,

Thanks for posting the question in Microsoft Q&A forum.

After looking at the task you are doing and the error, I assume you have followed the steps mentioned in the standard Microsoft documentation: Tutorial: Develop an ASP.NET web application with Azure Cosmos DB for NoSQL.

Consider refactoring your .net code using the answer mentioned in the similar issue posted by user here: CosmosDB System.ArgumentNullException: 'Value cannot be null. (Parameter 'authKeyOrResourceToken')'

Let us know if this helped in your case. If not, we will investigate further.