Quick video tutorials from the folks that made Canvas, a group that now includes you. These are mostly around 5 minutes. You have 5 minutes right?

Extending Canvas: Writing a custom function in a plugin

Writing a custom function to add forex data to Canvas

Starting with the Canvas plugin boilerplate, this video will take you through the steps required to create a custom function to get forex data using the 1force API.

Details about the 1force API can be found here, and functional code can be found in the canvas-extras repo.

Note that you'll need to have X-Pack installed in Elasticsearch and Kibana in order to start up Canvas and use your plugin. See the X-Pack download page for details.