Start Sense tasks using REST API

Use Butler’s REST API to start Sense tasks

If the Butler config file is properly set up it’s possible to start any Sense task by doing a PUT HTTP call to /v4/reloadtask/{taskId}/start endpoint.

A great use case is to have upstream systems that feed Qlik Sense with data trigger a Sense task when new data is available.
That way Sense doesn’t have to poll for new data, with less system resources used in both upstream system and in Sense.

AND users get the new data as quickly as possible!

Helper functions available in .qvs file

If you what to start reload tasks from the Sense load script that is easy.

Just include the butler_subs.qvs file from the GitHub release package and you get (among many other things) a helper function that’s called StartTask. It takes a single taskId parameter, which means that starting a reload task from an app’s load script is as simple as

Call StartTask(<TaskId>)

The general Butler 5.0 demo app Butler 5.0 - demo app (many APIs!).qvf (link) contains such a demo (and many others).

Need to pass along parameters to a task? There’s a Sub for that!

Sometimes you need to send parameters to a reload task (or rather to the load script of the app associated with the task).
This can be done by using the StartTask_KeyValue helper function/Sub.

That Sub takes a taskId as parameter (similarly to its StartTask sibling), but it also takes parameters for a full key-value pair:

Call StartTask_KeyValue('fbf645f0-0c92-40a4-af9a-6e3eb1d3c35c', 'MyNamespace', 'An important key', 'The value', 3000)

The parameters are

  • The namespace to store the key-value pair in (required).
  • The key (required).
  • The value (required).
  • An time-to-live valud in milliseconds (optional). When the ttl times out the key-value pair is automatically deleted.

Documentation about Butler’s key-value store is available here.

An example showing how task chaining with parameters can be done using key-values is found here.

Requirements for starting tasks via REST API

These config file settings must be set up before Butler can use the REST API to start tasks:

  • Connection to Qlik Sense:
    • Butler.configQRS.*
  • Configure REST server itself:
    • Butler.restServerConfig.enable: true
    • Butler.restServerConfig.serverHost: <IP or hostname where Butler’s REST server is running>
    • Butler.restServerConfig.serverPort:
  • Enable the start task API endpoint
    • Butler.restServerEndpointsEnable.senseStartTask: true

Seeing is believing

The video below is available at Ptarmigan Labs' YouTube channel and also in the Butler playlist.



Last modified 2021-02-24: v5.0.0 (f409521)