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RabbitMQ

{
  "addresses": ["rabbit:5672"],
  "virtual_host": "/",
  "username": null,
  "password": null,
  "default_queue": null,
  "tls": { "enabled": false, "client_certs": [], "trusted_certs": [], "trust_all": false, "hostname_verification": true },
  "topology": {
    "exchanges": [{ "name": "orders", "type": "topic", "durable": true, "auto_delete": false, "arguments": {} }],
    "queues": [{ "name": "billing", "type": "quorum", "durable": true, "auto_delete": false, "arguments": { "x-max-length": 10000 } }],
    "bindings": [{ "exchange": "orders", "queue": "billing", "routing_key": "order.*", "arguments": {} }]
  }
}

addresses is required. An address without a port is reached on 5671 with TLS, 5672 without.

Topology​

The topology (empty by default) is declared as the client starts, before anything else. What exists already, the same way, is left as it is; a declaration the broker refuses (a queue that exists with other arguments) keeps the connection unavailable, saying which. Queues are classic, quorum or stream (the last two durable, and not auto deleted). arguments are the AMQP arguments (x-message-ttl, x-dead-letter-exchange, x-max-length, ...).

Publishing​

Through one channel with publisher confirms: a publish is done once the broker has taken the message. Messages are published mandatory: a message no queue gets is reported as a failed result, instead of being dropped in silence. Options: queue (the default exchange, routed to that queue), or exchange and routing_key.

Consuming​

  • A queue: its consumers share its messages (that is what a queue is). A group is refused: a queue already is one.
  • An exchange and a routing_key: a queue of its own, bound to them, gone with the subscription: every subscriber gets every message.
  • prefetch (100): what the broker sends ahead. at-most-once acks as the message leaves the subscription, at-least-once once it is handed over; what was not acked goes back to the queue.

Streams​

A queue of the stream type is an append-only log. Reading it does not take its messages away, and a subscription starts where it is told (x-stream-offset): from=earliest, an offset (offset_from, each event carries its rabbitmqstreamoffset), a date (from_timestamp, to the second: a stream dates its chunks of messages), or from now on. The server-sent events consumer resumes a stream right after the last message a client got. A queue the topology declares as a stream is known as one; otherwise say stream=true. The other queues refuse to replay.