luisgg / aurex-meta Goto Github PK

Introduction
============
The aurex-meta source package generates binary metapackages for aurex (in a similar way to ubuntu-meta), but with some important differences:
 - 'self-contained metapackages': seeds are not stored in external repositories, but included in the source, just like when I write 'lliurex-meta' some time ago ...
 - 'multiples sources/origins support': This is the most significant innovation in relation to {Ubuntu|LliureX}-meta. Aurex metapackages are built from multiples archive repository URL's and multiple distributions (-updates, -security, o anything else ...) support.
 - '(reprepro) filter-list creation': aurex-meta can generate filter-list files (in the format of dpkg --get-selections) for each source. These files can beused with reprepro to update the distribution repository from multiple sources.

Aurex-meta is a good example of the aurex project philosophy: "NOT an Ubuntu derivative, just an add-on", and is a very useful tool to generate custom metapackages/repositories merging Ubuntu with other repos as PPAs, derivatives or local repositories, "picking" the best of each source to generate a single repository.

Metapackages and seeds
======================
Metapackages are built using "standard ubuntu-like seeds" (not transgenic seeds at this moment", so you must read the documentation of Ubuntu's 'germinate' tool.
Seeds are stored under directory 'seeds' (surprise !!!). There are tree subdirs:
	- $CURRENT_DIST (lucid): aurex specific and changes
        - ubuntu.$CURRENT_DIST / platform.$CURRENT_DIST : original seeds from Ubuntu
DO NOT CHANGE files under ubuntu.$CURRENT_DIST / platform.$CURRENT_DIST. To modify an original Ubuntu seed, copy the file under seeds/$CURRENT_DIST and edit. The edited file will overridethe original one (under ubuntu.$CURRENT_DIST or platform.$CURRENT_DIST).
The provided script 'update-seeds' download and updates original Ubuntu seeds from launchpad in directories ubuntu.$CURRENT_DIST / platform.$CURRENT_DIST. In case of change, old ubuntu seeds are stored in ubuntu.$CURRENT_DIST.<TIMESTAMP> or platform.$CURRENT_DIST.<TIMESTAMP> as backup. Sorry, but no "changes inspection" tools are includes, so use 'diff -uNr ...' or your favorite diff utility.

Configuration
=============
The basic configuration file is 'aurex-meta.conf'. The files is just sourced in update-scripts. The variable names are easy to understand (IMHO). This variables are basically used by the update scripts to expand templates (see templates section in this file). Empty varibles are usually generated in scripts, so be careful when changing the file.

Templates and variables
=======================
Some files (like the germinate configuration file 'update.cfg') are generated from templates. The templates can refer variable with the notation: _@_VARIABLENAME_@_. The template filenames use file extension '.in' 'as usual'.
Variables must be included in aurex-meta.conf, NO OTHER VARIABLES will be expanded. Scripts can change the variable value before expansion, but the variable must appear in aurex-meta.conf (because of that the presence of empty variables).
Files associated to templates are automatically replaced with template expansion in update-scripts, so do not edit directly the generated files, make the required changes in the templates or update variable values in the configuration file.

Update and generate metapackages
================================
The 'update-metapackages' script uses germinate-update-metapackage to grow seeds into the final depends and recommends package lists. The script uses custom option --multiple-dists, so the aurex patched version is required.
The script generates the required configuration file for germinate (update.cfg) from the template 'update.cfg.in', the 'aurex-meta.conf' configuration file and the 'sources' directory (explained in the next section).

sources
=======
the directory 'sources' contains arbitrary files (with standard 'sources.list' format). This files will be used to configure 'archive_base/default:' parameter in the germinate-update-metapackage configuration, acting as "apt package sources" to generate package lists from seeds.
You can supply a '.list' sources-list file or a '.list.in' template to generate the source.

reprepro package lists
======================
'update-lists' script generates and updates ".pkg" files in 'lists' directory. The script generates a file for each 'sources' file, with the same name but with '.pkg' extension. The files are in the format of dpkg --get-selections, so they are suitable to use as filter with reprepro.
In order to generate lists, 'update-lists' simulates the installation of CURRENT metapackages in a debootstrap chroot environment to detect required packages from each source.
The chroot contains an standard Ubuntu debootstrap. The required customization can be archieved AFTER debootstrap installation with some OPTIONALS variables in aurex-meta.conf. The variables and action order is:
 - CUSTOM_DEBOOTSTRAP_SOURCESLIST: filename of sources.list file to replace /et(apt/sources.list in chroot. If not specified, directory sources is expanded, and all the resulting sources.list files concatenated.
 - CUSTOM_DEBOOTSTRAP_COPY: (local) directory to copy (rsync) into root directory of debootstrap. You can use this option to override any file in chroot.
 - CUSTOM_DEBOOTSTRAP_PKGS: space separated list of packages to install into the chroot
 - CUSTOM_DEBOOSTRAP_CMD: custom command to execute in the chroot after debootstrap, custom install and custom copy. The next step is just the simulated installation of metapackages.
'update-lists' supports option "--current-target=<DIRNAME>" to re-use a debootstrap dir to speed the process. Customization is not skipped.
Note that 'update-lists' uses debootstrap and REQUIRES root privileges.

update scripts and package building
===================================
The full process is:
 1.- run update-seeds, verify Ubuntu changes (if any) and edit your own seeds.
 2.- run update-metapackages, to update metapackage lists. If required, verify changelog, and add binary packages to debian/control.
 3.- build the debian packages and submit then to your own repo.
 4.- run update-lists and use the generated files to update your repository with repro.

Notice that after adding new metapackages (in step 2), you must complete step 3 BEFORE using these metapackages in seeds, because germinate-updatemetapackage uses CURRENT repositories to validate seeds.


That's folks. Enjoy, feel free to test and report bugs and improvements to <[email protected]>