RabbitMQ

RabbitMQ

RabbitMQ is a message broker. In essence, it accepts messages from producers, and delivers them to consumers. In-between, it can route, buffer, and persist the messages according to rules you give it.

The RabbitMQ server is an implementation of an Advanced Message Queuing Protocol (AMQP) broker. It is written on the widely-used Erlang/Open Telecom Platform (OTP), an "always available‟ platform that has been in production use in carrier grade telcos since the late 1990s. The core server is unusually compact, with only 12,000 lines of code. Because RabbitMQ implements the open AMQP protocol, it is not necessary to know Erlang, and many users prefer to manage the broker using Java or Ruby.

RabbitMQ, and messaging in general, uses these terms:

• Producing: means nothing more than sending

• Producer "P": A program that sends messages

• Queue: is the mailbox that lives inside RabbitMQ. The messages that flow through RabbitMQ and your applications can be stored only inside a queue. A queue is an infinite buffer where you can store as many messages as you like

Many producers can send messages that go to one queue - many consumers can try to receive data from one queue.

• Consuming: is receiving messages
• Consumer "C": is a program that mostly waits to receive messages

Producer, consumer, and broker do not have to reside on the same machine; indeed in most applications they don't.

AMQ

The Advanced Message Queuing Protocol (AMQP) is an open standard for passing business messages between applications or organizations.  It connects systems, feeds business processes with the information they need and reliably transmits onward the instructions that achieve their goals.

The defining features of AMQP are message orientation, queuing, routing (including point-to-point and publish-and-subscribe). AMQP mandates the behaviour of the messaging provider and client to the extent that implementations from different vendors are truly interoperable, in the same way as SMTP, HTTP, FTP, etc. have created interoperable systems. Consequently any tool that can create and interpret messages that conform to this data format can interoperate with any other compliant tool irrespective of implementation language

AMQP is designed to efficiently support a wide variety of messaging applications and communication patterns. It provides flow controlled, authentication and/or encryption based on SASL and/or TLS, message-oriented communication with message-delivery guarantees such as:

• at-most-once (where each message is delivered once or never)
• at-least-once (where each message is certain to be delivered, but may do so multiple times)
• exactly-once (where the message will always certainly arrive and do so only once)