KDE software is split into different components, many of which can be built by kdesrc-build. Understanding this organization will help you properly select the software modules that you want built.

Selecting which of the possible modules to build is controlled by the configuration file. After the global section is a list of modules to build, bracketed by module ... end module lines. An example entry for a module is shown in Example 2.1, “Example module entry in the configuration file”.

module module-name
    # Options for this module go here, example:
    make-options -j4 # Run 4 compiles at a time
end module

kdesrc-build only builds the modules you have listed in your configuration file. In addition, the modules are built in the order specified in the configuration file. For this reason you should ensure that the order of modules in your configuration file is consistent with the organization given in the section called “KDE Software Organization”.

There is a sample file that comes with kdesrc-build called kdesrc-buildrc-sample. It is recommended to copy this file to a file called ~/.kdesrc-buildrc (Note the leading period in front of kdesrc-buildrc!). Afterwards, edit the new file to adjust the default options to your liking. (Each option is described in more detail in Chapter 4, Configuring kdesrc-build). The default modules should be enough to ensure a fairly complete KDE installation, however you can remove many of the modules that show up after kdebase if you'd like to save disk space or build time.

kdesrc-build is usually able to guess where to download the source code for a given module quite easily, by using your setting for svn-server and the module name for each module to create a single Subversion URL, which describes exactly where to download the source code from.

With the move to Git, many larger Subversion modules were further sub-divided in the process, and there was no guarantee of where to find a module based just on the module name. Because of this, a concept called “module sets” was developed for kdesrc-build 1.12.1.

By using a module set, you can quickly declare many Git modules to be downloaded and built, as if you'd typed out a separate module declaration for each one. The repository option is handled specially to setup where each module is downloaded from, which every other option contained in the module set is copied to every module generated in this fashion.

global
    git-repository-base kde-git kde:
end global

module qt
    # Options removed for brevity
end module

module-set kde-support-libs
    repository kde-git
    use-modules automoc attica akonadi
end module-set

# Other modules as necessary...
module kdesupport
end module

In Example 2.2, “Using module sets” a brief module set is shown. When kdesrc-build encounters this module set, it acts as if, for every module given in use-modules, that an individual module has been declared, with its repository equal to the module-set's repository followed immediately by the given module name.

In addition, other options can be passed in a module set, which are copied to every new module that is created this way. By using module-set it is possible to quickly declare many Git modules that are all based on the same repository URL. In addition, since kdesrc-build 1.13, it is possible to give module-sets a name (as shown in the example), which allows you to quickly refer to the entire group of modules from the command line.

Module sets use the options

With the migration of KDE source code to be hosted on git.kde.org, there has been an explosive growth in the number of modules (for instance, a single Subversion module called kdegraphics becomes 16 different Git modules).

This was done mostly because each Git module contains the entire project history (this is actually less wasteful of disk space than it sounds for the vast majority of KDE repositories as Git is highly efficient at storing repositories).

KDE allows for grouping Git repositories into collections of related modules (e.g. kdegraphics). These modules can themselves be grouped (e.g. KDE Software Compilation). Git doesn't recognize these groupings, but kdesrc-build can be configured to handle these groups.

The way this is done is by using module sets. Instead of using a specific git:// repository, or a repository name created by git-repository-base, a special repository name, “kde-projects” is used.

kdesrc-build will recognize that the kde-projects repository requires special handling, and adjust the build process appropriately. Among other things, kdesrc-build will:

The following example shows how to use the KDE module database to install the Phonon multimedia library.

module-set media-support
    # This option must be kde-projects to use the module database.
    repository kde-projects

    # This option chooses what modules to look for in the database.
    use-modules phonon/phonon phonon-gstreamer phonon-vlc
end module-set

The following example is perhaps more realistic, and shows a feature only available with the KDE module database: Building all of the KDE graphics applications with only a single declaration.

module-set kdegraphics
    # This option must be kde-projects to use the module database.
    repository kde-projects

    # This option chooses what modules to look for in the database.
    use-modules kdegraphics/libs kdegraphics/*
end module-set

There are two important abilities demonstrated here:

You might decide that you'd like to build all programs within a KDE module grouping except for a given program.

For instance, the kdeutils group includes a program named kremotecontrol. If your computer does not have the proper hardware to receive the signals sent by remote controls then you may decide that you'd rather not download, build, and install kremotecontrol every time you update kdeutils.

As of kdesrc-build 1.16, you can achieve this by using the ignore-modules configuration option.

module-set utils
    repository kde-projects

    # This option chooses what modules to look for in the database.
    use-modules kdeutils

    # This option "subtracts out" modules from the modules chosen by use-modules, above.
    ignore-modules kremotecontrol
end module-set