diskimage-builder/diskimage_builder/elements/pkg-map/README.rst
Ian Wienand 97c01e48ed Move elements & lib relative to diskimage_builder package
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
2016-11-01 17:27:41 -07:00

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=======
pkg-map
=======
Map package names to distro specific packages.
Provides the following:
* bin/pkg-map::
usage: pkg-map [-h] [--element ELEMENT] [--distro DISTRO]
Translate package name to distro specific name.
optional arguments:
-h, --help show this help message and exit
--element ELEMENT The element (namespace) to use for translation.
--distro DISTRO The distro name to use for translation. Defaults to
DISTRO_NAME
--release RELEASE The release to use for translation. Defaults to
DIB_RELEASE
* Any element may create its own pkg-map JSON config file using the
one of 4 sections for the release/distro/family/ and or default.
The family is set automatically within pkg-map based on the
supplied distro name. Families include:
+ redhat: includes centos, fedora, and rhel distros
+ debian: includes debian and ubuntu distros
+ suse: includes the opensuse distro
The release is a specification of distro; i.e. the distro and
release must mach for a translation.
The most specific section takes priority.
An empty package list can be provided.
Example for Nova and Glance (NOTE: using fictitious package names
for Fedora and package mapping for suse family to provide a good
example!)
Example format::
{
"release": {
"fedora": {
"23": {
"nova_package": "foo" "bar"
}
}
},
"distro": {
"fedora": {
"nova_package": "openstack-compute",
"glance_package": "openstack-image"
}
},
"family": {
"redhat": {
"nova_package": "openstack-nova",
"glance_package": "openstack-glance"
},
"suse": {
"nova_package": ""
}
},
"default": {
"nova_package": "nova",
"glance_package": "glance"
}
}
Example commands using this format:
pkg-map --element nova-compute --distro fedora nova_package
Returns: openstack-compute
pkg-map --element nova-compute --distro rhel nova_package
Returns: openstack-nova
pkg-map --element nova-compute --distro ubuntu nova_package
Returns: nova
pkg-map --element nova-compute --distro opensuse nova_package
Returns:
* This output can be used to filter what other tools actually install
(install-packages can be modified to use this for example)
* Individual pkg-map files live within each element. For example
if you are created an Apache element your pkg-map JSON file
should be created at elements/apache/pkg-map.