削减Uber的CI成本

Hundreds of engineers can commit changes to a single repository in modern software development, particularly within large and fast-paced technology companies [1]. This situation presents a significant challenge: efficiently managing these changes, quickly resolving conflicts, and ensuring that the mainline remains green. A mainline is considered green if all build steps—compilation, unit tests, and UI tests—successfully execute for every commit point in the repository history. Maintaining a green mainline is critical for enabling rapid development and deployment cycles. However, as highlighted in the Bernardo and Alenca study [2], landing changes rapidly while keeping the mainline green becomes increasingly difficult as the codebase grows in size and complexity, further compounded by the concurrency of changes submitted by numerous developers.

在现代软件开发中，数百名工程师可以对单个代码库进行更改，特别是在大型和快速发展的科技公司中 [1]。这种情况带来了一个重大挑战：高效管理这些更改，快速解决冲突，并确保主干保持绿色。如果所有构建步骤——编译、单元测试和UI测试——在代码库历史中的每个提交点都成功执行，则主干被视为绿色。维护绿色主干对于实现快速开发和部署周期至关重要。然而，正如Bernardo和Alenca的研究 [2] 所强调的，随着代码库的规模和复杂性增加，快速提交更改的同时保持主干绿色变得越来越困难，这进一步加剧了众多开发者提交的更改的并发性。

CI (Continuous Integration) systems enable rapid iteration while safeguarding the stability of production systems. As organizations scale, so do the challenges in managing code integration, resolving conflicts, and minimizing the risk of regressions. Without robust CI systems, teams face delayed releases, increased operational overhead, and decreased developer velocity.

CI（持续集成）系统能够快速迭代，同时保护生产系统的稳定性。随着组织的扩展，管理代码集成、解决冲突和最小化回归风险的挑战也随之增加。没有强大的 CI 系统，团队面临发布延迟、运营开销增加和开发者效率下降的问题。

SubmitQueue is designed to continuously land changes efficiently while maintaining a green mainline. More than 4,500 engineers across Uber’s global development centers rely on it every day, contributing to thousands of microservices and tens of mobile apps. This system processes tens of thousands of changes each month. This scale involves managing hundreds of millions of lines of code across six major monorepos and seven programming languages. Subm...