Lately I've been doing a lot of work managing batch-processing tasks. Broadly speaking, there are 2 types of trigger for such a task: time-based and logic-based. The former can be easily done by cron/scheduled jobs. The latter can be a bit tricky, mostly because it can involve dependencies on other tasks. In this post, I will talk about how I've been using the AWS Simple Workflow service (SWF) to take some of the headache out of orchestrating tasks.