How can I create variables dynamically from datasource plugin?

How can I create variables dynamically from my datasource plugin?

in case this is not possible so how can I populate a custom variable dynamically from a datasource plugin?

Welcome

for example you can do this using the query in your variable creation screen
name is countries

select name from countries

name the variable countries and it should be available as $countries with a list of country names.

What is your specific datasource?