Keeping Master Green at Scale – Uber Engineering ‘SubmitQueue’

Green refers to a master branch that always successfully compiles and passes all build steps, the opposite being red. It guarantees an always green master branch at scale: all build steps (e.g., compilation, unit tests, UI tests) successfully execute for every commit point. SubmitQueue has been in production for over a year, and can scale to thousands of daily commits to giant monolithic repositories.

Source: eng.uber.com