如何在heroku上的多个worker dynos上构建计划任务，其中每个worker dyno都会继续执行一批不同的行

Question

I'm trying to build an application on heroku, and it's pretty clear how to add more worker dynos to finish the same task.

However, what i'm trying to do here is to create a cron job that runs multiple worker dynos where every one of them runs an incremental batch of tasks, imagine the following code:

// those are variables coming from a cron
var limit;
var start;

connection.query("SELECT * FROM posts LIMIT " + limit + ", " + start, function(error, videos) {
    // do something
});

What I need to do here is as follows: create a clock worker, that runs a script every 2 hours, this should scale the worker dynos number up, pass to every one of them the limit and the start variables and scale back down when the tasks finish.

I would really appreciate any help/guidance with that.

Answer 1

I haven't actually had to do this yet but its in my list of to-dos. At first glance I didn't see any way to do this with heroku but the solution that is looking most worthwhile is to build EC2 AMIs with Node running on a known port; launch them with the scheduler and pass out jobs to the listening apps. As long as you pass in the db connection string your EC2s will be able to pull info from your db and pass back results.