[BUG] AzureServiceTokenProvider.GetAccessTokenAsync no longer works with Visual Studio 16.3

Describe the bug

I work on a project that uses Azure Managed Identities. AzureServiceTokenProvider.GetAccessTokenAsync() is used to get a token, and to debug locally a token provided by Visual Studio is used. After upgrading to Visual Studio 16.3 this no longer works. I have verified this to be the case on two different computers after upgrading to Visual Studio 16.3.

I don’t know if this is a problem with Visual Studio or the NuGet package but the exception is thrown by the NuGet package so I’m reporting it here.

Exception or Stack Trace

Parameters: Connection String: RunAs=Developer; DeveloperTool=VisualStudio, Resource: https://management.azure.com, Authority: . Exception Message: Tried to get token using Visual Studio. Access token could not be acquired. Exception for Visual Studio token provider Microsoft.Asal.TokenService.exe : Token response is not in the expected format. Exception Message: There was an error deserializing the object of type Microsoft.Azure.Services.AppAuthentication.TokenResponse. Encountered unexpected character ‘D’.

   at Microsoft.Azure.Services.AppAuthentication.AzureServiceTokenProvider.<GetAuthResultAsyncImpl>d__14.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Runtime.CompilerServices.ConfiguredTaskAwaitable`1.ConfiguredTaskAwaiter.GetResult()
   at Microsoft.Azure.Services.AppAuthentication.AzureServiceTokenProvider.<GetAuthenticationResultAsync>d__18.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Runtime.CompilerServices.ConfiguredTaskAwaitable`1.ConfiguredTaskAwaiter.GetResult()
   at Microsoft.Azure.Services.AppAuthentication.AzureServiceTokenProvider.<GetAccessTokenAsync>d__16.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter`1.GetResult()
   at UserQuery.<RunUserAuthoredQuery>d__0.MoveNext()

To Reproduce

Use Visual Studio 16.3 and configure an Azure account in Tools > Options > Azure Service Authentication > Account Selection.

Create a new instance of AzureServiceTokenProvider with connection string "RunAs=Developer; DeveloperTool=VisualStudio" and then call GetAccessTokenAsync("https://management.azure.com") to get a token.

Code Snippet

var connectionString = "RunAs=Developer; DeveloperTool=VisualStudio";
var azureServiceTokenProvider = new AzureServiceTokenProvider(connectionString);
var token = await azureServiceTokenProvider.GetAccessTokenAsync("https://management.azure.com");

Expected behavior

GetAccessTokenAsync should return a token that can be used to authenticate with Azure based on the configured account in Visual Studio and not throw an exception.

Screenshots

Setup (please complete the following information):

• OS: Windows 10 Pro 1903 18362.356
• IDE: Visual Studio 16.3.0
• Version of the Library used: Microsoft.Azure.Services.AppAuthentication 1.3.1

Additional context

None.

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[vlardn]

For me, the problem appeared after upgrading to Visual Studio 2019 16.4.0 from the previous version. I’ve found that this was caused by invalid TokenProvider path, so I was forced to change content of “%LOCALAPPDATA%.IdentityService\AzureServiceAuth\tokenprovider.json” file:

{ "TokenProviders": [ { "Path": "c:\\program files (x86)\\microsoft visual studio\\2019\\enterprise\\common7\\ide\\extensions\\1rzmhu0l.2xx\\TokenService\\Microsoft.Asal.TokenService.exe", "Arguments": [ "--serviceHubConfig", "\"C:\\Program Files (x86)\\Microsoft Visual Studio\\2019\\Enterprise\\Common7\\servicehub.config.json\"" ], "Preference": 0 }, { "Path": "c:\\program files (x86)\\microsoft visual studio\\2019\\enterprise\\common7\\ide\\extensions\\qglq5p5b.btx\\TokenService\\Microsoft.Asal.TokenService.exe", "Arguments": [ "--serviceHubConfig", "\"C:\\Program Files (x86)\\Microsoft Visual Studio\\2019\\Enterprise\\Common7\\servicehub.config.json\"" ], "Preference": 1 }, { "Path": "c:\\program files (x86)\\microsoft visual studio\\2019\\enterprise\\common7\\ide\\extensions\\4rin0bzc.yf5\\TokenService\\Microsoft.Asal.TokenService.exe", "Arguments": [ "--serviceHubConfig", "\"C:\\Program Files (x86)\\Microsoft Visual Studio\\2019\\Enterprise\\Common7\\servicehub.config.json\"" ], "Preference": 2 } ] }

to only one valid entry (note a new extensions folder - “…\extensions\ys2aolp3.2rs”):

{ "TokenProviders": [ { "Path": "c:\\program files (x86)\\microsoft visual studio\\2019\\enterprise\\common7\\ide\\extensions\\ys2aolp3.2rs\\TokenService\\Microsoft.Asal.TokenService.exe", "Arguments": [ "--serviceHubConfig", "\"C:\\Program Files (x86)\\Microsoft Visual Studio\\2019\\Enterprise\\Common7\\servicehub.config.json\"" ], "Preference": 0 } ] }

and then everything started to work again!

[loarabia]

@Liversage awesome that actually makes this much easier to dive into. Let me see if I can get someone on the ASAL side of things to weigh in next week.