general-mq

General purposed interfaces for message queues. Now we provide the following implementations:

• AMQP 0-9-1
• MQTT

By using these classes, you can configure queues with the following properties:

• Unicast or broadcast.
• Reliable or best-effort.

Notes

• MQTT uses shared queues to implement unicast.
• AMQP uses confirm channels to implement reliable publish, and MQTT uses QoS 1 to implement reliable publish/subscribe.

Relationships of Connections and Queues

The term connection describes a TCP/TLS connection to the message broker. The term queue describes a message queue or a topic within a connection. You can use one connection to manage multiple queues, or one connection to manage one queue.

A queue can only be a receiver or a sender at a time.

Connections for sender/receiver queues with the same name

The sender and the receiver are usually different programs, there are two connections to hold two queues.

For the special case that a program acts both the sender and the receiver using the same queue:

• The AMQP implementation uses one Channel for one queue, so the program can manages all queues with one connection.
• The MQTT implementation MUST uses one connection for one queue, or both sender and receiver will receive packets.

Test

Please prepare a RabbitMQ broker and a EMQX broker at localhost for testing.

• To install using Docker:

  $ docker run --rm --name rabbitmq -d -p 5672:5672 rabbitmq:management-alpine $ docker run --rm --name emqx -d -p 1883:1883 emqx/emqx

Then run the test:

$ cargo test --test integration_test -- --nocapture

Example

Launch RabbitMQ and then run AMQP example:

$ cargo run --example simple

Launch EMQX and then run MQTT example:

$ RUN_MQTT= cargo run --example simple