Layman

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Layman is Gentoo's primary overlay management tool, offering centralized repository management for end users.

Features

With app-portage/layman users can manage their overlays in a simple, centralized manner. The Layman application provides an overview of available remote overlay repositories and allows the user to select one or more for the system. Once selected, the user can update the repositories (similar to emerge --sync), add local overlays, and more.

Installation

USE flags

Installing Layman is a breeze. First check the USE flags that the Layman package supports; most of the USE flags trigger which kinds of remote repository types layman supports (such as git repositories, cvs repositories, etc.).

Optional USE flags for app-portage/layman:
USE flag (what is that?) Default Recommended Description
bazaar No Support for dev-vcs/bzr based overlays.
cvs No Support dev-vcs/cvs based overlays
darcs No Support dev-cvs/darcs based overlays
g-sorcery No Support app-portage/g-sorcery based overlays
git No Support dev-vcs/git based overlays
mercurial No Support dev-cvs/mercurial based overlays
squashfs No Support mounting squashfs image overlays locally read-only
subversion No Support dev-vcs/subversion based overlays
sync-plugin-portage No Install the sys-apps/portage sync module
test No Workaround to pull in packages needed to run with FEATURES=test. Portage-2.1.2 handles this internally, so don't set it in make.conf/package.use anymore

Emerge

Next install the Layman package:

root #emerge --ask app-portage/layman

Configuration

There are two methods how to integrate layman into portage. Recent sys-apps/portage versions support both methods at the same time, so there is no need to configure portage (except configurations mentioned in this section).


This article has some todo items:
  • Please specify version number for very old (portage) versions

Using 'make.conf' method (older method)

This is an older method, still widely used. Very old portage versions support only this method.

Note
Modifying layman.cfg might be unnecessary, depending on layman version.

Configure layman to use make.conf method in /etc/layman/layman.cfg. Older layman installations will have this already set:

FILE /etc/layman/layman.cfg
# Repository config types used by layman
# (repos.conf, make.conf)
conf_type : make.conf

Insert a reference to Layman in /etc/portage/make.conf

root #echo "source /var/lib/layman/make.conf" >> /etc/portage/make.conf

Adding the source command to the /etc/portage/make.conf (performed in the command above) will ensure that Portage, when asked, will check the content of the various overlays managed by Layman in the /var/lib/layman/make.conf file. In effect, it will update the PORTDIR_OVERLAY variable with directories Layman uses. If a special directory has been previously defined for PORTDIR_OVERLAY in /etc/portage/make.conf, make sure its value is not overwritten with the value Layman provides.

FILE /etc/portage/make.confEnsuring that layman's PORTDIR_OVERLAY is not overwritten
PORTDIR_OVERLAY="${PORTDIR_OVERLAY} ..."

Using 'repos.conf' method (default method for app-portage/layman-2.3.0 or later )

This method uses a new portage plugins system. Layman will create its configuration file in /etc/portage/repos.conf/ directory. There is no need for PORTDIR_OVERLAY changes in /etc/portage/make.conf.

Configure layman to use repos.conf method in /etc/layman/layman.cfg. New installations of layman will probably have this already set correctly:

FILE /etc/layman/layman.cfg
# Repository config types used by layman
# (repos.conf, make.conf)
conf_type : repos.conf

Create /etc/portage/repos.conf/ directory, if it does not exist yet.

If you have app-portage/layman-2.3.0 or later installed, you can force a rebuild of layman's repos.conf files:

root #layman-updater -R

Usage

Basic invocations

The Layman man page (see External resources) provides a full overview of the available functions within Layman. However, for most users, the following commands suffice for overlay management activities.

To fetch and display a list of all the overlays available through official references:

root #layman -L

To add an overlay in the list generated by the local list:

root #layman -a <name>

To add an unofficial overlay

root #layman -o <url of repository xml file> -f -a <name>

To remove an overlay from the local list:

root #layman -d <name>

To update a specific overlay:

root #layman -s <name>

To update all overlays:

root #layman -S

Mountable overlays with layman-mounter

Since the release of layman-2.2.0, support for squashfs overlay types has been included. layman will interact with squashfs overlays by mounting them as read-only on the filesystem. On the initial install of the squashfs overlay, it will be mounted as read-only. However, after a reboot the overlay will no longer be mounted and the ebuilds in that overlay will not be accessible by the system.

In order to assist users in handling these mountable overlays, a utility was added that goes by the name of layman-mounter.

To find all overlays that are currently mounted, type:

root #layman-mounter -l

To find all overlays that are installed by layman that can be mounted, type:

root #layman-mounter -L

To mount the mountable overlays, type:

root #layman-mounter -m <name>

To unmount the overlays, type:

root #layman-mounter -u <name>

Setting overlay priorities with Layman

As each overlay is assigned a unique priority, layman provides a simple way of defining priorities for overlays it manages. For more information about overlay priorities see the overlay article.

The file /var/lib/layman/installed.xml contains some information about the overlays, among which is the priority attribute in the repo tag. The number there determines only the priority relative to the other overlay entries, 50 is the default value. layman then analyses this file and sets the order of the overlay entries in the PORTDIR_OVERLAY variable defined in /var/lib/layman/make.conf.

As the file /var/lib/layman/make.conf is automatically generated by layman based on the settings in /var/lib/layman/installed.xml, it is strongly recommended that only /var/lib/layman/installed.xml is used to set the priorities.

To add a personal overlay, and to ensure that the overlay has a higher priority, add the overlay before /var/lib/layman/make.conf is sourced.

FILE /var/lib/layman/make.confExample layman overlays setting
PORTDIR_OVERLAY="
/home/jdoe/gamerlay
/var/lib/layman/lisp
/var/lib/layman/Spring
${PORTDIR_OVERLAY}" #the variable defined in /etc/portage/make.conf is now expanded
                    #when /var/lib/layman/make.conf is sourced in /etc/portage/make.conf

However, this can be also "fooled" by defining the PORTDIR_OVERLAY in /etc/portage/make.conf after /var/lib/layman/make.conf has been sourced.

FILE /etc/portage/make.confCustom overlay setting
source /var/lib/layman/make.conf #this sources the PORTDIR_OVERLAY variable defined by layman.
                                 #however, the variable expanded by layman was empty
PORTDIR_OVERLAY="/home/user/overlay ${PORTDIR} ${PORTDIR_OVERLAY}" #now the layman defined overlays take precedence,
                                                                   #but the user defined overlay still has the lowest priority

This "trick" is merely an opportunity offered by shell variable expansion.

Adding custom overlays

To add overlays which are not listed when layman -L is ran, find their repository XML files and add them using the -o option.
Example: repositories.xml in brother-overlay

In case the overlay does not provide a repository XML file, crete it manually in the /etc/layman/overlays folder.

For example, if Larry the cow were to create an overlay:

FILE /etc/layman/overlays/larry.xmlLarry the cow's ngix overlay
<?xml version="1.0" ?>
 
<repositories version="1.0">
	<repo priority="50" quality="experimental" status="unofficial">
		<name>larry</name>
		<description>nginx server for the barn computer from Larry the cow.</description>
		<homepage>https://github.com/gentoo/nginx-overlay</homepage>
		<owner>
			<email>larry@gentoo.org</email>
		</owner>
		<source type="git">https://github.com/gentoo/nginx-overlay.git</source>
	</repo>
</repositories>

NEW: With the addition of layman-2.2.0 a new utility was added to assist users in this process that goes by the name of layman-overlay-maker. As long as the overlay information has been properly added via the prompts,layman-overlay-maker will create a XML defined overlay and save into /etc/layman/overlays or the specified in the layman configuration file for overlay_defs.

layman-overlay-maker can become a useful tool in assisting users who would like to submit a patch to have their overlays added to the official repositories.xml file.

To use the utility simply invoke it by name:

root #layman-overlay-maker

and go through its prompts until completion.

When finished run:

root #layman -a <name>

See also

External resources