Intermittent Error: Cannot Set AccessToken Property in .NET Core 8 with SQL Server

Question

Description: I am encountering an intermittent error in my .NET 8 application when trying to establish a database connection using the Microsoft.Data.SqlClient library. The issue occurs sporadically during runtime, resulting in the following unhandled exception:

vbnet
Copy code
System.InvalidOperationException: Cannot 

Key Details:

Environment:

• Application: w3wp.exe
  • CoreCLR Version: 8.0.824.36612
    • .NET Version: 8.0.8
    Connection String: My connection string specifies Authentication along with other parameters for Azure Active Directory authentication. The AccessToken property is set programmatically for some specific scenarios. Error Pattern:

    - The error occurs intermittently and is not consistent.
    
       - Restarting the application sometimes resolves the issue temporarily.
    
       **Code Reference**: The exception points to the `DbContextOptionsBuilder` configuration in my `Program.cs` file:
    
       ```javascript
       csharp
       Copy code
       services.AddDbContext<MyDbContext>((serviceProvider, options) =>
    

{

           ```

           
           **Observation**: The error suggests that both `AccessToken` and `Authentication` cannot be used simultaneously. However, the configuration works most of the time, and the error appears unpredictably.
```Request for Help:

1. Has anyone encountered similar intermittent issues when using `AccessToken` with Azure Active Directory in SQL Server connections?

1. Are there specific guidelines or best practices to handle such scenarios?

1. Could this be related to token caching, thread safety, or connection pool issues?

Any insights or suggestions would be greatly appreciated!**Description:**

I am encountering an intermittent error in my .NET 8 application when trying to establish a database connection using the Microsoft.Data.SqlClient library. The issue occurs sporadically during runtime, resulting in the following unhandled exception:


```powershell
vbnet
Copy code
System.InvalidOperationException: Cannot 

Key Details:

Environment:

• Application: w3wp.exe
  • CoreCLR Version: 8.0.824.36612
    • .NET Version: 8.0.8
    Connection String:
    My connection string specifies Authentication along with other parameters for Azure Active Directory authentication. The AccessToken property is set programmatically for some specific scenarios. Error Pattern:

    - The error occurs intermittently and is not consistent.
    
       - Restarting the application sometimes resolves the issue temporarily.
    
       **Code Reference**:  
       The exception points to the `DbContextOptionsBuilder` configuration in my `Program.cs` file:
    
       ```javascript
       csharp
       Copy code
       services.AddDbContext<MyDbContext>((serviceProvider, options) =>
    

{

           ```

           
           **Observation**:  
           The error suggests that both `AccessToken` and `Authentication` cannot be used simultaneously. However, the configuration works most of the time, and the error appears unpredictably.
```Request for Help:

1. Has anyone encountered similar intermittent issues when using `AccessToken` with Azure Active Directory in SQL Server connections?

1. Are there specific guidelines or best practices to handle such scenarios?

1. Could this be related to token caching, thread safety, or connection pool issues?

Any insights or suggestions would be greatly appreciated!

Answer 1

I tried to analyse your issue and based on my reaserch I found primarly many similar problems to yours.

First thing, I think that the error you are having is because of the AAD authentication is being in conjunction with the AccessToken property in Microsoft.Data.SqlClient because you set the AccessToken property programmatically, the Authentication keyword in your connection string should not be used.

You can remove it dynamically :

if (useAccessToken)
{
    var builder = new SqlConnectionStringBuilder(connectionString);
    builder.Remove("Authentication"); // Remove conflicting property
    connectionString = builder.ToString();
}

Don't forget that you can have this issue if your token is expiring and in this case you need to use Microsoft.Identity.Client to fetch and cache tokens since it better handle token renewal.

var app = ConfidentialClientApplicationBuilder.Create(clientId)
    .WithClientSecret(clientSecret)
    .WithAuthority(new Uri(authority))
    .Build();
var token = await app.AcquireTokenForClient(scopes).ExecuteAsync();
var accessToken = token.AccessToken;

Another behaviour you can get is the AccessToken property being not compatible with connection pooling because tokens are tied to a single connection lifespan so you may need to disable it :

options.UseSqlServer(connectionString, sqlOptions =>
{
    sqlOptions.EnableRetryOnFailure();
    sqlOptions.CommandTimeout(60); // Adjust as necessary
    sqlOptions.UseConnectionPooling(false);
})
;

One last point, if you have multiple threads attemping to use or renew the same token so you can use the below :

private static readonly SemaphoreSlim semaphore = new SemaphoreSlim(1, 1);
public async Task<string> GetAccessTokenAsync()
{
    await semaphore.WaitAsync();
    try
    {
        // Token acquisition logic
    }
    finally
    {
        semaphore.Release();
    }
}

What I highly recommend is you need to have a retry catch mechanism to better understand the issue :

services.AddDbContext<MyDbContext>((serviceProvider, options) =>
{
    options.UseSqlServer(connectionString, sqlOptions =>
    {
        sqlOptions.EnableRetryOnFailure(
            maxRetryCount: 5,
            maxRetryDelay: TimeSpan.FromSeconds(10),
            errorNumbersToAdd: null);
    });
});