Google Datastore authentication issue - C#

Question

I'm trying to connect to the Google Datastore on my account with service account credentials file (which I've created according to the documentation), but I'm encountering with authentication error while trying to insert an entity:

Grpc.Core.RpcException: Status(StatusCode=Unauthenticated, Detail="Exception occured in metadata credentials plugin.")

My code is:

var db = DatastoreDb.Create("myprojectid");
Entity entity = new Entity{
 Key = db.CreateKeyFactory("mykindname").CreateIncompleteKey()
};
var keys = await db.InsertAsync(new[] { entity });

The GOOGLE_APPLICATION_CREDENTIALS variable refers to the credentials file and when calling GoogleCredential.GetApplicationDefaultAsync() to see if the credentials object is valid it indeed looks good...

I saw some earlier examples which used the GetApplicationDefaultAsync function togehether with some DatastoreService object - but I couldn't find the DatastoreService object (probably it was there in old versions...) in the latest .Net API: Google.Cloud.Datastore.V1

Notice that I don't want to use the other authenticaiton methods:

1) Using the gcloud cli.

2) Running from Google environment (app engine for example).

Any idea how to solve this?

Answer 1

After the great help of Jon Skeet the issue was solved.

The authentication issues can occur if you don't reference all the required Datastore dlls. Make sure that all the dlls are referenced on the project that are running the calls to the Datastore.

I've added the Google Datastore lib via the NuGet to my test project and everything worked!

Notice that in such cases it is recommended to enable gRPC logging. `(For exmaple: GrpcEnvironment.SetLogger(new ConsoleLogger()), there you'll probably see if there were issues loading several dlls...

Answer 2

Authentication can be broken if your system clock is significantly incorrect. Check your system time, and fix it if necessary, then try authenticating against Datastore again.