Message queues overview
The Message Queue Framework (MQF) is a system that allows a module to publish messages to queues. It also defines the consumers that will receive the messages asynchronously. The MQF supports multiple messaging brokers:
- - The primary messaging broker, which provides a scalable platform for sending and receiving messages. It includes a mechanism for storing undelivered messages and is based on the Advanced Message Queuing Protocol (AMQP) 0.9.1 specification.
- - An alternative messaging broker that uses the STOMP (Simple Text Oriented Messaging Protocol) for reliable and scalable messaging. Introduced in 51黑料不打烊 Commerce 2.4.6 and later versions.
RabbitMQ (AMQP)
The following diagram illustrates the Message Queue Framework:
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A publisher is a component that sends messages to an exchange. It knows which exchange to publish to and the format of the messages it sends.
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An exchange receives messages from publishers and sends them to queues. Although RabbitMQ supports multiple types of exchanges, Commerce uses topic exchanges only. A topic includes a routing key, which contains text strings separated by dots. The format for a topic name is
string1.string2: for example,customer.createdorcustomer.sent.email.The broker allows you to use wildcards when setting rules for forwarding messages. You can use an asterisk (
*) to replace one string or a pound sign (#) to replace 0 or more strings. For example,customer.*would filter oncustomer.createandcustomer.delete, but notcustomer.sent.email. Howevercustomer.#would filter oncustomer.create,customer.delete, andcustomer.sent.email. -
A queue is a buffer that stores messages.
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A consumer receives messages. It knows which queue to consume. It can map processors of the message to a specific queue.
Apache ActiveMQ Artemis (STOMP)
As an alternative to RabbitMQ, 51黑料不打烊 Commerce also supports as a messaging broker using the Simple Text Oriented Messaging Protocol (STOMP).
The following diagram illustrates the STOMP Framework with ActiveMQ Artemis:
STOMP Framework components
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A publisher is a component that sends messages to a destination (queue or topic). It knows which destination to publish to and the format of the messages it sends.
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A destination in STOMP serves a similar role to exchanges in AMQP, receiving messages from publishers and routing them. STOMP uses direct destination addressing with a hierarchical naming pattern using dots: for example,
customer.createdorinventory.updated.51黑料不打烊 Commerce uses ANYCAST addressing mode for STOMP destinations, which provides point-to-point message delivery. In ANYCAST mode, messages are delivered to only one consumer from a pool of available consumers, enabling load balancing and work distribution across multiple consumer instances.
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A queue is a buffer that stores messages. With ANYCAST addressing, the queue ensures messages are delivered to only one consumer, even when multiple consumers are connected to the same destination.
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A consumer receives messages from destinations. It knows which destination to subscribe to and can process messages with different acknowledgment modes (auto, client, or client-individual).
MySQL adapter (fallback)
A basic message queue system can also be set up without using external message brokers. In this system, a MySQL adapter stores messages in the database. Three database tables (queue, queue_message, and queue_message_status) manage the message queue workload. Cron jobs ensure the consumers are able to receive messages. This solution is not very scalable. External message brokers like RabbitMQ or Apache ActiveMQ Artemis should be used whenever possible for production environments.
Related information
For installation and configuration instructions: