Rufus Scheduler :first_in option unknown with cron - ruby

Question

I am trying to use the Rufus Scheduler (within Dashing) to schedule a cron job, but also have it run once upon the server spinning up. I am following the readme here where it is saying to do the following:
scheduler.cron '00 14 * * *', :first_in => '3d' do
# ... every day at 14h00, but start after 3 * 24 hours
end
When I try to do this, I get the following error in my job:
`cron': unknown option: :first_in (ArgumentError)
Has anyone come across this?

Answer 1

Dashing is using rufus-scheduler 2.0.24 ( https://github.com/Shopify/dashing/blob/55f90939eae4d6eb64822fd3590f694418396510/dashing.gemspec#L24 ) which doesn't support the first_in feature for cron.
First_in was introduced for cron in rufus-scheduler 3.0.
It seems you're reading the rufus-scheduler 3.x documentation instead of the 2.x one.
The documentation for rufus-scheduler is at https://github.com/jmettraux/rufus-scheduler#rufus-scheduler , on top of it, there is the link to the 2.x documentation ( https://github.com/jmettraux/rufus-scheduler/blob/two/README.rdoc ). You'll have better luck there.
A 2.x alternative would be:
scheduler.in '3d' do
scheduler.cron '00 14 * * *' do
# ... every day at 1400
end
end