Scale By the Bay 2018

We’re shifting gears to leverage new technologies created since we built Medium 5 years ago, but we need to incrementally gain benefits from the new system along the way and we can’t afford to let it hinder feature development. By taking advantage of GraphQL’s flexibility and our existing infrastructure, we’re able to make widespread yet gradual architectural changes! Come see how Medium is changing lanes without slowing down. Anyone thinking about moving to GraphQL (or thinking about migrating an exisiting architecture in general) can benefit from this talk, but especially anyone who is building their own GraphQL server or needs practical advice on how to successfully migrate a legacy system to GraphQL without “stopping the world,” getting defunded partway through, or building a system no one uses. Abstract Migrating an entire system to new tools and frameworks isn’t an easy task. And doing that while not impacting feature development? That’s even harder. We’ll walk through how Medium is migrating off of our existing system, without hindering product development, and while also incrementally gaining the benefits of a new system along the way. We’ll go over the design of our new architecture, our phased migration approach, and how the layered structure of our GraphQL server (written in Scala with Sangria) was integral to the success of both. - Goals of the migration - Design of the new system - Phased approach - Phase 1: developer experience - IDLs (protobuf) + GraphQL - Phase 2: services + gRPC - GraphQL server layers - Fetchers - Repos - Schema (derivation) - Putting it all together