Scheduler

In distributed applications, it is often necessary to schedule messages for deferred execution. Brighter provides built-in scheduling capabilities to handle that scenarios.

Scheduling Methods

The IAmACommandProcessor interface includes methods for scheduling messages:

public interface IAmACommandProcessor
{
    // Synchronous methods
    string Send<T>(DateTimeOffset at, T command);
    string Send<T>(TimeSpan delay, T command);
    string Publish<T>(DateTimeOffset at, T @event);
    string Publish<T>(TimeSpan delay, T @event);
    string Post<T>(DateTimeOffset at, T @event);
    string Post<T>(TimeSpan delay, T @event);

    // Asynchronous methods
    Task<string> SendAsync<T>(DateTimeOffset at, T command);
    Task<string> SendAsync<T>(TimeSpan delay, T command);
    Task<string> PublishAsync<T>(DateTimeOffset at, T @event);
    Task<string> PublishAsync<T>(TimeSpan delay, T @event);
    Task<string> PostAsync<T>(DateTimeOffset at, T @event);
    Task<string> PostAsync<T>(TimeSpan delay, T @event);
}

Scheduler Types

Brighter supports three scheduling mechanisms:

1. Transport-Based Scheduler

Uses native transport APIs (e.g., Azure Service Bus EnqueuedTimeUtc or AWS SQS delay).

Limitations:

• No support for modifying/canceling schedules on some platforms.

• Some transport can have limitation, like AWS SQS that only support max of 15 minutes of delay

2. Message-Based Scheduler

Fallback for transports without native scheduling (e.g., AWS SQS <15min delays).

Example:

messageScheduler.Scheduler(TimeSpan.FromMinutes(1), new DailyReportEvent());

3. Request-Based Scheduler

Directly schedules via IAmACommandProcessor methods (Send, Publish, Post).

Respects sync/async execution flow:

// Synchronous scheduling
commandProcessor.Send(TimeSpan.FromMinutes(1), new MyCommand());
commandProcessor.Publish(DateTimeOffset.UtcNow.AddSeconds(10), new MyCommand());

// Asynchronous scheduling
await commandProcessor.PublishAsync(TimeSpan.FromHours(1), new MyEvent());
await commandProcessor.PostAsync(DateTimeOffset.UtcNow.AddSeconds(10), new MyCommand());