Microsoft Orleans Reminders for ADO.NET

Introduction

Microsoft Orleans Reminders for ADO.NET provides persistence for Orleans reminders using ADO.NET-compatible databases (SQL Server, MySQL, PostgreSQL, etc.). This allows your Orleans applications to schedule persistent reminders that will be triggered even after silo restarts or grain deactivation.

Getting Started

To use this package, install it via NuGet:

dotnet add package Microsoft.Orleans.Reminders.AdoNet

You will also need to install the appropriate ADO.NET provider for your database:

# For SQL Server
dotnet add package System.Data.SqlClient

# For MySQL
dotnet add package MySql.Data

# For PostgreSQL
dotnet add package Npgsql

Example - Configuring ADO.NET Reminders

using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.DependencyInjection;
using Orleans.Configuration;
using Orleans.Hosting;
using Example;

// Create a host builder
var builder = Host.CreateApplicationBuilder(args);
builder.UseOrleans(siloBuilder =>
{
    siloBuilder
        .UseLocalhostClustering()
        // Configure ADO.NET as reminder storage
        .UseAdoNetReminderService(options =>
        {
            options.Invariant = "System.Data.SqlClient";  // For SQL Server
            options.ConnectionString = "Server=localhost;Database=OrleansReminders;User ID=orleans;******;";
        });
});

// Build and start the host
var host = builder.Build();
await host.StartAsync();

// Get a grain reference and use it
var grain = host.Services.GetRequiredService<IGrainFactory>().GetGrain<IReminderGrain>("my-reminder-grain");
await grain.StartReminder("DailyReport");
Console.WriteLine("Reminder started successfully!");

// Keep the host running until the application is shut down
await host.WaitForShutdownAsync();

Example - Using Reminders in a Grain

using System;
using System.Threading.Tasks;
using Orleans;
using Orleans.Runtime;

namespace Example;

public interface IReminderGrain : IGrainWithStringKey
{
    Task StartReminder(string reminderName);
    Task StopReminder();
}

public class ReminderGrain : Grain, IReminderGrain, IRemindable
{
    private string _reminderName = "MyReminder";

    public async Task StartReminder(string reminderName)
    {
        _reminderName = reminderName;
        
        // Register a persistent reminder
        await RegisterOrUpdateReminder(
            reminderName,
            TimeSpan.FromMinutes(2),  // Time to delay before the first tick (must be > 1 minute)
            TimeSpan.FromMinutes(5)); // Period of the reminder (must be > 1 minute)
    }

    public async Task StopReminder()
    {
        // Find and unregister the reminder
        var reminder = await GetReminder(_reminderName);
        if (reminder != null)
        {
            await UnregisterReminder(reminder);
        }
    }

    public Task ReceiveReminder(string reminderName, TickStatus status)
    {
        // This method is called when the reminder ticks
        Console.WriteLine($"Reminder {reminderName} triggered at {DateTime.UtcNow}. Status: {status}");
        return Task.CompletedTask;
    }
}