Entities: Make `InitializeState` support Async operations about durabletask-dotnet

[jviau]

You can workaround this by using an EnsureInitializeAsync pattern. InitializeState will kick off the task to populate the state, and then each operation will await that task.

private readonly Task? _initialization;

public async Task MyOperation()
{
    await EnsureInitializedAsync();
}

protected T InitializeState(..)
{
   async InitializeAsync()
   {
        // async work
   }

    _initialization = InitializeAsync();
    return default(T); // InitializeAsync 
}

private Task InitializeAsync()
{
    // perform async work
    this.State = T; // set this.State
}

private ValueTask EnsureInitializedAsync()
{
    return _initialization is null ? default : new(_initialization);
}

[jviau]

@gorillapower

Yes, returning default(T) would be fine there. InitializeState is just a convenience method for populating state when there is none. I updated my sample to show that.

You could also set it in InitializeState and then populate its contents in InitializeAsync.

[jhinm112]

Thread is also blocked in my initializeState because async operations are not supported

[gorillapower]

Thanks @jviau. Would this pattern still work with this method signature?

protected override T InitializeState(TaskEntityOperation operation){}

as I need to return T not void (as the entity inherites from TaskEntity<T>) and it looks like the base class will store the returned value in the base.State property.

Full Code Example

public class T : TaskEntity<T>
{
    public void MyMethod() { }
    
    [Function(nameof(T))]
    public static Task RunEntityAsync([EntityTrigger] TaskEntityDispatcher dispatcher)
    {
        return dispatcher.DispatchAsync<T>();
    }
    
    protected override T InitializeState(TaskEntityOperation operation)
    {
        //inject EnsureInitializeAsync pattern here?
        T state = new();
        return state; 
    }
}

Also worth noting, an additional alternative would be to use the functions based syntax which would allow the populating of the state inside the DispatchAsync()