Can't WaitForResourceAsync KnownResourceStates.Finished

[eerhardt]

Is there an existing issue for this?

• I have searched the existing issues

Describe the bug

It's not possible to get notification when a resource has been stopped/finished when after await app.StopAsync();.

I'm trying to write a test that uses a Docker Volume, and when the test is done, it deletes the volume. However, the volume is still in use even after await app.StopAsync(); returns, which means the container using the volume is still running.

I'd like a way to get notified when the resource/container is finished so I can delete the volume.

One reason this isn't possible today is that WaitForResourceAsync cancels once the app is stopping here:

aspire/src/Aspire.Hosting/ApplicationModel/ResourceNotificationService.cs

Lines 89 to 93 in 681f2e7

	public async Task<string> WaitForResourceAsync(string resourceName, IEnumerable<string> targetStates, CancellationToken cancellationToken = default)
	{
	using var watchCts = CancellationTokenSource.CreateLinkedTokenSource(_applicationStopping, cancellationToken);
	var watchToken = watchCts.Token;
	await foreach (var resourceEvent in WatchAsync(watchToken).ConfigureAwait(false))

Once the app is stopping, it cancels this loop, which means we won't get more notifications about the resource.

Expected Behavior

I'd like to get a notification when the container is finished.

Steps To Reproduce

await using var app = await appHost.BuildAsync();
var resourceNotificationService = app.Services.GetRequiredService<ResourceNotificationService>();
await app.StartAsync();

await app.StopAsync();

await resourceNotificationService.WaitForResourceAsync("webfrontend", KnownResourceStates.Finished).WaitAsync(TimeSpan.FromSeconds(30));

Exceptions (if any)

No response

.NET Version info

No response

Anything else?

cc @DamianEdwards @karolz-ms @mitchdenny

[karolz-ms]

@eerhardt and I chatted. We think the main issue is that as soon as app.StopAsync() is called, the resource service and ApplicationExecutor stops listening to resource changes. So even if DcpOptions.DeleteResourcesOnShutdown is set, there is no way for the Aspire model to learn that the container (or any resource for that matter) has changed state, or was deleted.

It would probably make sense to change this behavior and differentiate between stopping the application (which would stop application executables and containers, but preserve the Aspire model and its ability to get state updates) vs disposing of the application (which would dispose of the model, stop DCP orchestrator etc.)

[ealeykin]

@karolz-ms I'm observing the same behavior even before StopAsync - not getting a Finished notification when the target host exits. Well, from time to time I get it, but most of the time it's stuck on waiting till the timeout.