Usage, Costs, and Benefits of Continuous Integration in Open-Source Projects Michael Hilton Timothy Tunnell Kai Huang Oregon State University, USA University of Illinois, USA University of Illinois, USA
[email protected] [email protected] [email protected] Darko Marinov Danny Dig University of Illinois, USA Oregon State University, USA
[email protected] [email protected] ABSTRACT deployment of software. For example, such automation has Continuous integration (CI) systems automate the compila- been reported [22] to help Flickr deploy to production more tion, building, and testing of software. Despite CI rising as than 10 times per day. Others [40] claim that by adopting a big success story in automated software engineering, it has CI and a more agile planning process, a product group at received almost no attention from the research community. HP reduced development costs by 78%. For example, how widely is CI used in practice, and what are These success stories have led to CI growing in interest some costs and benefits associated with CI? Without answer- and popularity. Travis CI [17], a popular CI service, reports ing such questions, developers, tool builders, and researchers that over 300,000 projects are using Travis. The State of make decisions based on folklore instead of data. Agile industry survey [48], with 3,880 participants, found In this paper, we use three complementary methods to 50% of respondents use CI. The State of DevOps report [49] study the usage of CI in open-source projects. To understand finds CI to be one of the indicators of "high performing IT which CI systems developers use, we analyzed 34,544 open- organizations".