[DevBox] Start the Dev Box while configuring

[huzaifa-d]

Summary of the pull request

The PR addresses the issue where the Dev Box was no running while trying to apply a configuration. The Dev Box is now started, instead of erroring out.

##Before

##After

Validation steps performed

Manually

PR checklist

• Closes #[Environments reliability] Dev Box Configuration error: The Dev Box isn't running. Please start the Dev Box and try again  devhome#3669

[bbonaby]

I'm wondering if we could just call the IComputeSystem StartAsync() method instead since that starts a threadpool timer that wakes up every minute to check the progress of the operation. If we pass the DevBoxInstance to the WingetConfigWrapper then we'd be able to do that. Then we could use a wait event handle within a while loop that waits every minute.

Something like this e.g

if (_devBox.GetState() != ComputeSystemState.Running))
{
    await _devBox.StartAsync(string.Empty);
    var startCancellationTokenSource = new CancellationTokenSource();
    startCancellationTokenSource.CancelAfter(TimeSpan.FromMinutes(30));

    while (_devBoxStartEvent.WaitOne(TimeSpan.FromMinutes(1)))
    {
        if (_devBox.GetState() == ComputeSystemState.Running)
        {
            break;
        }

        if (startCancellationTokenSource.IsCancellationRequested)
        {
            throw new InvalidOperationException(Resources.GetResource(DevBoxErrorStateKey))
        }
    }
 }

This would reduce the code amount by a good amount I believe. You can either use a ManualResetEvent or a Task.Delay like you've been using, but you'd have to have an extra variable to keep the loop alive. Also note, we need to increase the time Dev Home's configuration waits too here: https://github.com/microsoft/devhome/blob/ca1ca04bac3325bc68e29f8f478453d2b4f85971/tools/SetupFlow/DevHome.SetupFlow/Models/ConfigureTargetTask.cs#L419

[sshilov7]

+1. One question: would we send _devBoxStartEvent event if the device is already running by the time code in _devBox.StartAsync actually runs (since everything is async and in the cloud the device state can change between our last check and Start command)? This is probably not an issue since we check state every minute which, I assume, would be updated.

[huzaifa-d]

Good idea; changed.

[bbonaby]

@sshilov7 I just wanted to let you know that your assumption is right. Although that got me thinking of one more edge case:

1. If the _devBox.StartAsync method returns an error then we'd be waiting for 15 minutes for no reason. @huzaifa-d, could you add an error check for this one?

[bbonaby]

we should use GetState() too so we don't need to await it

[bbonaby]

we could use the HalfMinutePeriod in the constants we're adding in this PR for this.

[bbonaby]

we probably don't need to wrap this in an else statement since throwing would exist the method

[bbonaby]

Maybe we should say something like "{0} couldn't be started. Please try starting the Dev Box manually and try again."

where {0} is the name of the Dev Box

[bbonaby]

@sshilov7 I just wanted to let you know that your assumption is right. Although that got me thinking of one more edge case:

1. If the _devBox.StartAsync method returns an error then we'd be waiting for 15 minutes for no reason. @huzaifa-d, could you add an error check for this one?

[sshilov7]

Do we need this 3-minute wait? Are chances that VM can start earlies so low? The code below checks the state once in 30 seconds. I wouldn't think sending 1 request per 30 seconds is too often.