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
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 tofalse
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 tofalse
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 tofalse
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 tofalse
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