Allow downloading a detailed log in CI
Currently it is possible to download the raw logs from a build in CI, and one of the original use cases for this was for easier reading of large logs. However, would also be useful to show limited logs in the UI, but make detailed debug-level logs available for download if needed. Showing highly detailed logs in the UI is usually just unnecessary noise that makes it hard to see what happened, but when something goes wrong they are essential.
Making gitlab understand different log levels is likely to be very difficult, since different tools indicate log levels in different ways, and there isn't a reliable way of determining what lines are important and what are just detail. My proposal is to simply publish a file named
gitlab-ci.log as the detailed logs if it was written during the build. This leaves it up to the user to decide what it relevant detail, and then just dump it into the file. Practically, this is little different from creating an artifact out of
gitlab-ci.log, but it would be implicit in all builds and could have specific UI.