An Analysis of 35+ Million Jobs of Travis CI

Abstract: Travis CI handles automatically thousands of builds every day to, amongst other things, provide valuable feedback to thousands of open-source developers. In this paper, we investigate Travis CI to firstly understand who is using it, and when they start to use it. Secondly, we investigate how the developers use Travis CI and finally, how frequently the developers change the Travis CI configurations. We observed during our analysis that the main users of Travis CI are corporate users such as Microsoft. And the programming languages used in Travis CI by those users do not follow the same popularity trend than on GitHub, for example, Python is the most popular language on Travis CI, but it is only the third one on GitHub. We also observe that Travis CI is set up on average seven days after the creation of the repository and the jobs are still mainly used (60%) to run tests. And finally, we observe that 7.34% of the commits modify the Travis CI configuration. We share the biggest benchmark of Travis CI jobs (to our knowledge): it contains 35,793,144 jobs from 272,917 different GitHub projects.