Exchanges | RabbitMQ

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https://www.rabbitmq.com/docs/exchanges

What is an Exchange

Take messages from publishers and route those messages to queues, streams or other exchanges.

Types

Determines how messages are routed to there destinations.

Fanout

Every message is published to every destination.

Topic

Uses pattern matching on the routing key to determine the destination.

The routing key is split into segments by a . delimiter.

* - matches on exactly 1 segment

# - matches on 0-to-many segments

Examples

audit.events.#
matches - audit.events, audit.events.thing, audit.events.thingy.thing
ignores - audit.users

audit.events.*
matches - audit.events, audit.events.thing
ignores - audit.users, audit.events.thingy.thing

Direct

Routes messages to destinations that exactly match the routing key.

Default

A direct exchange that always exists, where a binding exists for all queues, where the routing key is the queue name.

What are Bindings

A binding links a exchange to a destination.

They have the following:

• Source name: the source exchange

• Destination name: the name of the queue, stream or exchange

• Destination type: queue for queues and streams, exchange for exchanges

Alternate Exchanges

Used to receive messages from exchanges where the message was unrouteable.

Alternate Exchanges are typically fanout with a single unrouted queue.

How to define

It is recommended to define them using policies.