redb.Route.RabbitMQ 4.0.1

redb.Route.RabbitMQ

RabbitMQ transport for redb.Route. Consumer and producer with exchanges, queues, dead-letter, priority, TTL, and the official RabbitMQ.Client 7.x.

Installation

dotnet add package redb.Route.RabbitMQ

Usage

URI Format

rabbitmq://queue-name?host=localhost&exchange=my-exchange&routingKey=order.*

Fluent DSL

using redb.Route.RabbitMQ.Fluent;

// Consumer with exchange binding
From(Rabbit.Queue("orders")
        .Host("rabbitmq.local")
        .Username("guest").Password("guest")
        .Exchange("order-exchange", "topic")
        .RoutingKey("order.new")
        .PrefetchCount(50)
        .ConcurrentConsumers(4))
    .Log("Order received")
    .To("direct://process");

// Producer with dead-letter
From("direct://outbound")
    .To(Rabbit.Queue("events")
        .Host("rabbitmq.local")
        .Durable()
        .MessageTtl(86400000)
        .DeadLetterExchange("dlx")
        .DeadLetterRoutingKey("failed"));

Fluent Builder API

Most builder methods accept both constant values and IExpression for runtime resolution via the expression engine.

Consumer concurrency & acknowledgement

• .ConcurrentConsumers(N) is the single knob for consumer-side parallelism: it sets both the channel's AMQP consumer-dispatch concurrency and the app-level concurrency semaphore, so up to N messages from the queue are processed concurrently. Default 1 (strictly serial — message order preserved). With N > 1, ordering is not preserved and your processor must be thread-safe. Keep .PrefetchCount() ≥ N so the broker keeps the parallel slots fed.
• .AutoAck() switches the consumer to broker-side auto-acknowledge (at-most-once): the broker settles each delivery on hand-off, so a failed turn does not requeue. Default off (at-least-once: ack after a successful turn, nack-requeue on failure). Cannot be combined with .Transacted().

Part of

redb.Route — ESB & EIP Framework for .NET

Named connection factory

Keep credentials out of the route URI: register a factory in the context registry and reference it by name. A set-but-unknown name fails loud at startup — a typo can never silently fall back to inline URI parameters.

context.AddToRegistry("prod", new RabbitMQConnectionFactory
{
    Host = "rabbit.internal",
    Username = "svc",
    Password = secrets.RabbitPassword,
});
// rabbitmq://orders?connectionFactory=prod

Concurrency

The default is 1 concurrent consumer — the industry norm (Camel, Spring, the Azure SDK all ship 1): a single consumer preserves ordering and your handlers need no thread safety. Parallelism is an explicit opt-in:

concurrentConsumers=4       # a fixed worker count
concurrentConsumers=auto    # max(CPU count, 2) — the NServiceBus formula

Anything else — 0, a negative, a typo — fails at endpoint creation naming the option (the old int-typed option silently fell back to 1). Raising the value trades ordering for throughput: messages from the same queue are processed out of order, and your processors must be safe to run in parallel.