rabbitmq-server/deps/rabbitmq_recent_history_exchange

RabbitMQ Recent History Cache

Keeps track of the last 20 messages that passed through the exchange. Every time a queue is bound to the exchange it delivers that last 20 messages to them. This is useful for implementing a very simple Chat History where clients that join the conversation can get the latest messages.

Exchange yype: x-recent-history.

Installation

This plugin ships with RabbitMQ.

Like all other plugins, it must be enabled before it can be used:

[sudo] rabbitmq-plugins enable rabbitmq_recent_history_exchange

Usage

Creating an exchange

To create a recent history exchange, just declare an exchange providing the type "x-recent-history".

channel.exchangeDeclare("logs", "x-recent-history");

Providing a custom history length

Typically this exchange will store the latest 20 messages sent over the exchange. If you want to set a different cache length, then you can pass a "x-recent-history-length" argument to exchange.declare. The argument must be an integer greater or equal to zero.

For example in Java:

Map<String, Object> args = new HashMap<String, Object>();
args.put("x-recent-history-length", 60);
channel.exchangeDeclare("rh", "x-recent-history", false, false, args);

Preventing some messages from being stored

In case you would like to not store certain messages, just add the header "x-recent-history-no-store" with the value true to the message.

Disabling the Plugin

When you disable this plugin, it will delete all the cached messages.

License

See LICENSE.