Receiver¶

Sorting the List¶

You can specify the sorting keys and sorting direction when list receivers, using the option --sort. The --sort option accepts a string of format key1[:dir1],key2[:dir2],key3[:dir3], where the keys used are receiver properties and the dirs can be one of asc and desc. When omitted, Senlin sorts a given key using asc as the default direction.

For example, the following command sorts the receivers using the name property in descending order:

$ openstack cluster receiver list --sort name:desc

When sorting the list of receivers, you can use one of type, name, action, cluster_id, created_at.

Paginating the List¶

In case you have a huge collection of receiver objects, you can limit the number of receivers returned from Senlin server, using the option --limit. For example:

$ openstack cluster receiver list --limit 1

Yet another option you can specify is the ID of a receiver object after which you want to see the list starts. In other words, you don’t want to see those receivers with IDs that is or come before the one you specify. You can use the option --marker for this purpose. For example:

$ openstack cluster receiver list \
    --limit 1 --marker 239d7212-6196-4a89-9446-44d28717d7de

Combining the --marker option and the --limit option enables you to do pagination on the results returned from the server.

Webhook Receiver¶

When creating a webhook receiver, you are expected to use the option --cluster to specify the target cluster and the option --action to specify the action name. By default, the openstack cluster receiver create command line creates a receiver of type “webhook”. User can also explicitly specify the receiver type using the option --type, for example:

$ openstack cluster receiver create \
   --cluster test-cluster \
   --action CLUSTER_SCALE_OUT \
   --type webhook \
   test-receiver

Senlin service will return the receiver information with its channel ready to receive HTTP POST requests. For a webhook receiver, this means you can check the “alarm_url” field of the “channel” property. You can use this URL to trigger the action you specified.

The following command triggers the receiver by sending a POST request to the URL obtained from its channel property, for example:

$ curl -X POST <alarm_url>

Message Receiver¶

A message receiver is different from a webhook receiver in that it can trigger different actions on different clusters. Therefore, option --cluster and option --action can be omitted when creating a message receiver. Senlin will check if the incoming message contains such properties.

You will need to specify the receiver type “message” using the option --type when creating a message receiver, for example:

$ openstack cluster receiver create \
    --type message \
    test-receiver

Senlin service will return the receiver information with its channel ready to receive messages. For a message receiver, this means you can check the “queue_name” field of the “channel” property.

Once a message receiver is created, you (or some software) can send messages with the following format to the named Zaqar queue to request Senlin service:

{
  "messages": [
    {
      "ttl": 300,
      "body": {
        "cluster_id": "test-cluster",
        "action": "CLUSTER_SCALE_OUT",
        "params": {"count": 2}
      }
    }
  ]
}

More examples on sending message to a Zaqar queue can be found here:

http://git.openstack.org/cgit/openstack/python-zaqarclient/tree/examples