97c01e48ed
Currently we have all our elements and library files in a top-level directory and install them into <root>/share/diskimage-builder/[elements|lib] (where root is either / or the root of a virtualenv). The problem with this is that editable/development installs (pip -e) do *not* install data_files. Thus we have no canonical location to look for elements -- leading to the various odd things we do such as a whole bunch of guessing at the top of disk-image-create and having a special test-loader in tests/test_elements.py so we can run python unit tests on those elements that have it. data_files is really the wrong thing to use for what are essentially assets of the program. data_files install works well for things like config-files, init.d files or dropping documentation files. By moving the elements under the diskimage_builder package, we always know where they are relative to where we import from. In fact, pkg_resources has an api for this which we wrap in the new diskimage_builder/paths.py helper [1]. We use this helper to find the correct path in the couple of places we need to find the base-elements dir, and for the paths to import the library shell functions. Elements such as svc-map and pkg-map include python unit-tests, which we do not need tests/test_elements.py to special-case load any more. They just get found automatically by the normal subunit loader. I have a follow-on change (I69ca3d26fede0506a6353c077c69f735c8d84d28) to move disk-image-create to a regular python entry-point. Unfortunately, this has to move to work with setuptools. You'd think a symlink under diskimage_builder/[elements|lib] would work, but it doesn't. [1] this API handles stuff like getting files out of .zip archive modules, which we don't do. Essentially for us it's returning __file__. Change-Id: I5e3e3c97f385b1a4ff2031a161a55b231895df5b
debootstrap
Base element for creating minimal debian-based images.
This element is incomplete by itself, you'll want to use the debian-minimal or ubuntu-minimal elements to get an actual base image.
If necessary, a custom apt keyring and debootstrap script can be supplied to the debootstrap command via DIB_APT_KEYRING and DIB_DEBIAN_DEBOOTSTRAP_SCRIPT respectively. Both options require the use of absolute rather than relative paths.
Use of this element will also require the tool 'debootstrap' to be available on your system. It should be available on Ubuntu, Debian, and Fedora.
The DIB_OFFLINE or more specific DIB_DEBIAN_USE_DEBOOTSTRAP_CACHE variables can be set to prefer the use of a pre-cached root filesystem tarball. Setting DIB_OFFLINE may cause other element to use cached data, while DIB_DEBIAN_USE_DEBOOTSTRAP_CACHE only functions in the debootstrap element.
The DIB_DEBOOTSTRAP_EXTRA_ARGS environment variable may be used to pass extra arguments to the debootstrap command used to create the base filesystem image. If --keyring is is used in DIB_DEBOOTSTRAP_EXTRA_ARGS, it will override DIB_APT_KEYRING if that is used as well.
The DIB_DEBOOTSTRAP_CACHE variable can be used to cache the created root filesystem. By default this is 0 (disabled) and any other value enables this. If run in offline mode then the most recently cached rootfs is used instead of being built.
The DIB_DEBOOTSTRAP_DEFAULT_LOCALE environment variable may be used to configure the default locale of the base image. It defaults to C.UTF-8.
Note on ARM systems
Because there is not a one-to-one mapping of ARCH to a kernel package, if you are building an image for ARM on debian, you need to specify which kernel you want in the environment variable DIB_ARM_KERNEL. For instance, if you want the linux-image-mx5 package installed, set DIB_ARM_KERNEL to mx5.