What is the recommended approach for using GrainCancellationTokenSource in controllers

[akovac35]

Consider the following controller method:

GrainFactory is an IGrainFactory property in the controller.

        [HttpGet("LongTaskForCancellationTokenTesting")]
        public async Task<ActionResult> LongTaskForCancellationTokenTestingAsync(int seconds, CancellationToken cancellationToken)
        {
            using var grainCancellationTokenSource = new GrainCancellationTokenSource();
           
           // TODO grainCancellationTokenSource should have the Cancel method invoked
           // when cancellationToken has cancellation requested

            var grain = GrainFactory.GetGrain<IBlogGrain>(primaryKey: default);
            await grain.LongTaskForCancellationTokenTestingAsync(seconds, grainCancellationTokenSource.Token);

            return Ok();
        }

How do we link the cancellations of cancellationToken and grainCancellationTokenSource.Token in the above usage scenario? Is there a different pattern we should follow?

I also tried the following approach:

[HttpGet("LongTaskForCancellationTokenTesting")]
        public async Task<ActionResult> LongTaskForCancellationTokenTestingAsync(int seconds, CancellationToken cancellationToken)
        {
            using var grainCancellationTokenSource = new GrainCancellationTokenSource();
            using var grainCancellationToken = grainCancellationTokenSource.Token;
            using var registration = cancellationToken.Register(async () =>
            {
                try
                {
                    await grainCancellationTokenSource.Cancel();
                }
                catch (Exception ex)
                {
                    _logger.LogWarning(ex, ex.Message);
                }
            }
            );

            var grain = GrainFactory.GetGrain<IBlogGrain>(primaryKey: default);
            await grain.LongTaskForCancellationTokenTestingAsync(seconds, grainCancellationTokenSource.Token);

            return Ok();
        }

We get the following in logs:

warn: Orleans.Runtime.CancellationSourcesExtension[104001]
      Received a cancel call for token with id f01ee210-6c2a-4109-b6ff-f81c9d19cf6d, but the token was not found
info: Infrastructure.Blogs.Grains.BlogGrainCore[0]
      Finished long task

[akovac35]

It seems I am not the only one with not knowing how to link the tokens: #7977

[amoerie]

This might be of help as long as Orleans does not provide this out of the box: #7977 (comment)