I have recently added "Heroku Scheduler" addon to my heroku app...
I currently have a free heroku account and have the standard one web dyno....
Now I have set up a scheduled comment to run with scheduler... What will happen if I keep having 0 Worker dynos....
Do I get charged? Does my task just not run? Or does it fall back to the web dyno and gets queued on that one?
Your scheduled task with scheduler will run when you tell it to. It is similar to a worker process, however it runs then stops running once its finish instead of continually being billed. You are billed for the time it runs, but only that time. If your task is a short task running for 1 minute, on an hourly basis then you'd be billed at 24 minutes a day.
Just as an update to my previous comment, all the above as been obviated by the recent dyno and billing changes on heroku. You can now have a free web+workder dyno, provided it sleeps for at least 6 hours per day. There are also other changes making it cheaper to run a small hobby type project, even 24 hours per day.
As Craig mentioned, the scheduler addon will run a task for a set amount of time. It will use the time from your web dyno and it will not spawn a new dyno to complete the task. As a result, your web traffic will be queued during that duration (this is my current understanding of using the scheduler addon for heroku).
