LUV is not the answer: Continuous delivery of a model driven development platform

Abstract

The OutSystems Platform is a visual model-driven development and delivery platform that allows developers to create enterprise-grade cross platform web and mobile applications. The platform consists of several inter-dependent components, most notably Service Studio, the Platform Server, and LifeTime. Service Studio is an integrated development environment used to create applications that are then compiled by the Platform Server. LifeTime is used to stage applications between different environments (e.g., development, testing, production). Our meta-model is versioned using a version number that we call Last Upgrade Version (LUV). Service Studio, the Platform Server, and the models they create/process are associated with a particular LUV. As a general rule, a platform component is only able to process models with the same LUV as the component itself. This approach is not very flexible: a change to the meta-model requires releasing a new set of platform components that our customers then need to install. Although there's low resistance to installing new versions of Service Studio, the same is not true for the Platform Server. Thus, for all practical purposes LUV changes are tied to releases of major versions of the OutSystems Platform. In this paper we share the techniques that allowed us to transition to a Continuous Delivery process in which our meta-model can evolve freely with no impact on our installed base.