7 Generating change logs #

With source info tracking enabled, keg will write one or more source info files in addition to the image description in the output directory. In case the image description at hand is single-build, a single file log_sources is written, in case it is multi-build, a file log_sources_PROFILE is written for each profile. This allows for generating individual change logs for the resulting image binaries.

The source info logs contain detailed information about which bits from the keg-recipes tree was used to generate the image description. The source info log files will contain several lines of the following format:

root:/path/to/repository
range:start:end:/path/to/repository/file
/path/to/repository/file_or_dir

The first line specifies the repository location. There will be one for each keg-recipes directory given to keg. Lines starting with range: specify a part of a file in a repository. This is used to track the source location of each key that was in the final image dictionary. The third line format simply specifies a file or a directory in the repository that was used in the image description, and is used for configuration script snippets and overlay files.

This enables the change log generator to produce a change log using the git commit history, selecting only commits that apply to the generated image description.

The generated source info log files, together with the keg-recipes in the place and state they were used to generate the image description, can be used to generate change logs. The keg distribution contains a tool generate_recipes_changelog for that purpose. When called with a source log file as argument, generate_recipes_changelog will use the source information to select matching git messages and produce a change log in chronological order. There are parameters to to narrow down the applicable commit range as well as some formatting options. Refer to Section 3.2, “generate_recipes_changelog” command overview for details.

The keg distribution contains a module for integrating with the Open Build Service, an implementation of a so-called OBS Source Service. It supports automatic handling of change log generation. See Chapter 8, Keg OBS source service for details.