In my free time, I run a small blog that uses Amazon S3 to host static content and Amazon CloudFront to distribute it world-wide. I use a home-grown, static website generator to create and upload my blog content onto S3.
My blog uses two S3 buckets: one for staging and testing, and one for production. As a website owner, I want to update the production bucket with all changes from the staging bucket in a reliable and efficient way, without having to create and populate a new bucket from scratch. Therefore, to synchronize files between these two buckets, I use AWS Lambda and AWS Step Functions.
In this post, I show how you can use Step Functions to build a scalable synchronization engine for S3 buckets and learn some common patterns for designing Step Functions state machines while you do so.