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Document updated on Jan 21, 2022

AMQP driver for the Asynchronous Agent

The AMQP driver for Async agents allows you to have KrakenD consuming AMQP queues autonomously. Routines listening to AMQP queues will react by themselves to new events and push data to your backends.

This driver is different from the AMQP backend consumer. As opposed to endpoints, async agents do not require users to request something to trigger an action. Instead, the agents connect to the queue and fire an action when an event is delivered.

Async/AMQP Driver Configuration

The AMQP driver has to be placed inside the extra_config of the async component and allows you connect to an AMQP queue (e.g: RabbitMQ). The settings are as follows:

{
    "async/amqp": {
        "host": "amqp://guest:guest@localhost:5672/",
        "name": "krakend",
        "exchange": "foo",
        "durable": true,
        "delete": false,
        "exclusive": false,
        "no_wait": true,
        "prefetch_count": 5,
        "auto_ack": false,
        "no_local": true
    }
}
Fields of Async AMQP Driver
* required fields

auto_ack boolean
When KrakenD retrieves the messages, regardless of the success or failure of the operation, it marks them as ACK. When auto ACK is not used, only successful backend responses do the ACK, and failing messages are requeued. Defaults to false.
Defaults to false
delete boolean
When true, AMQP deletes the queue when there are no remaining connections. This option is not recommended in most of the scenarios. If for instance, the connectivity between KrakenD and AMQP is lost for whatever reason and it’s the only client, AMQP will delete the queue no matter the number of messages there are inside, and when KrakenD gets the connection again the queue won’t exist and future connections will recreate it again.
Defaults to false
durable boolean
Durable queues will survive server restarts and remain when there are no remaining consumers or bindings. Most of the times true is recommended, but depends on the use case.
Defaults to false
exchange * string
The entity name where messages are retrieved (it will be created, or it must have a topic type if already exists).
Example: "some-exchange"
exclusive boolean
When true, AMQP will allow a single KrakenD client to access the queue. This option is not recommended in environments where the gateway needs high availability and you have several instances running.
Defaults to false
host * string
The connection string, ends in slash. E.g: amqp://user:password@host:5672/.
name * string
The queue name.
no_local boolean
The no_local flag is not supported by RabbitMQ.
no_wait boolean
When true, do not wait for the server to confirm the request and immediately begin deliveries. If it is not possible to consume, a channel exception will be raised and the channel will be closed.
prefetch_count integer
The number of messages you want to prefetch prior to consume them.
Defaults to 10
prefetch_size integer
The number of bytes you want to use to prefetch messages.
Defaults to 0
Scarf

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