My users can save their preferred searches. Now I need to give them the possibility to subscribe to them in order to receive an email notification whenever new search results are available (like on Yahoo answers).
I already set up a Mailer that, when manually triggered, is working ok.
Now all I need to do is to call the mailer from a scheduled job but... I really ain't an expert on that field. So, among Whenever, Delayed_job, Sidekiq, Resque Scheduler & co. with which one (or combination of ones) should I go for this kind of task (long-running process with several mailing)?
EDIT
I developed a working example app, available on Github: NotiSearch.
It's pretty well documented so, if you are trying to develop something like it, I'd definitely recommend you to check it out.
PS: I chose to rely on whenever and delayed_job since they don't have external dependencies, if needed it should be easy enough to transition to a more scalable solution.