Prompter

A lil' helper library for Service Fabric actor's reminders.

It adds two things we found ourselves implementing over and over again:

Safe unregistering of reminders

No more try/catch blocks! Huzzah!
Single-use reminders

You're meant to unregister reminders, even if you're using the fire-once approach (dueTime: TimeSpan.FromMilliseconds(-1)). This makes that process automatic with PromptOnce. This is currently listed as a functional bug, but this will get you around it.
Correlation IDs

We use found it super useful to have an ID we could track across all of our services. This let's you track a GUID across reminders.

Usage

internal sealed class OrderActor : PromptableActor, IOrderActor
{
    public async Task PlaceOrder(OrderRequest req)
    {
        // Some internal logic, whatever
        var token = await SetOrderState(req);

        // Register a prompt to come back in seven days
        await PromptOnce(token, TimeSpan.FromDays(7));
    }

    protected override async Task OnPrompt(string name, byte[] context, TimeSpan due, TimeSpan period, Guid cid)
    {
        var token = name;
        var order = await GetOrderState(name);
        await SendEmailReminder(order);
    }
}

Setup

Install it from NuGet (Install-Package Prompter) and use one of the two options for integration.

A. Inheritance

internal sealed class MyActor : PromptableActor, IMyActor { }

B. Pretending you have traits

Setup a callback:

private Task OnPrompt(string name, byte[] context, TimeSpan due, TimeSpan period, Guid cid)
{
    // Do stuff
}

then add it to your actor's constructor:

private readonly Prompt _prompt;

public ActorFixture(ActorService svc, ActorId id)
: base(svc, id)
{
    _prompt = new Prompt(
        OnPrompt,
        GetReminder,
        RegisterReminderAsync,
        UnregisterReminderAsync,
        this);
}

and link the reminder callback to Prompter:

public Task ReceiveReminderAsync(string reminderName, byte[] state, TimeSpan dueTime, TimeSpan period) =>
    _prompt.ReceivePrompt(reminderName, state, dueTime, period);

It's awful, isn't it? I couldn't figure out a nicer way layer it on but I'm open to suggestions. (We have a bunch of these 'traits' we wanted to use and didn't like the idea of bundling them all into one base class.)

Logging

You should be logging everything like crazy, so I chucked in logs here too. That's why you (should) pass in the current actor when constructing Prompt. (I don't do anything else with it, I swear!)

The provider is Prompter-Prompt and it logs registers, unregisters and receives.

NickDarvey / Prompter