Mediarq.Deferred 1.5.1

Mediarq.Deferred

In-process deferred dispatch: SendLaterAsync/PublishLaterAsync queue a command or notification on a System.Threading.Channels-backed background worker instead of running its handler(s) inline — decoupling the caller from handler execution time. No external dependency, no persistent store: fills the gap between immediate Send/Publish and durable scheduling (Mediarq.Hangfire/Mediarq.Quartz) for the simple "reliable in-process fire-and-forget" case.

dotnet add package Mediarq.Deferred

Usage

builder.Services.AddMediarqDeferredDispatch();

public sealed class OrdersController(IDeferredDispatcher deferred)
{
    public async Task<IActionResult> Post(CreateOrder command)
    {
        await deferred.SendLaterAsync(command);       // returns immediately; a background worker dispatches it
        return Accepted();
    }
}

PublishLaterAsync works the same way for notifications:

await deferred.PublishLaterAsync(new OrderPlaced(orderId));

Both queue a closure capturing the concrete request; a single background worker (DeferredDispatchHostedService) drains the queue, running each item through the real ISender/IPublisher pipeline (validation, other behaviors, handlers) in its own DI scope. An exception in one item is logged and does not stop the worker from processing the next one.

What "reliable" means here

Queued work is in-memory only — it does not survive a process crash or restart. What it does guarantee is a graceful drain: on a normal host shutdown, the worker stops accepting new work and finishes everything already queued (bounded by the host's own shutdown timeout) instead of dropping it. If you need the item to survive a crash, or to run at a specific future time / on a cron schedule, use Mediarq.Hangfire or Mediarq.Quartz instead.

Backpressure

By default the queue is unbounded. Cap it with AddMediarqDeferredDispatch(o => { o.Capacity = 1000; o.FullMode = BoundedChannelFullMode.Wait; }) to apply backpressure to callers once full — see System.Threading.Channels.BoundedChannelFullMode for the other modes (DropOldest, DropNewest, DropWrite).

Learn more

Wiring extensions · Full README

MIT © Nicolas Rouffart