Platform Team/Guide/Sweets Usage

This guide describes how to use Sugar Labs' Packaging Management System. See also introduction page and Packaging guide.

Installation

Required packages

First, install PackageKit related packages. The following command will also install Polkit authentication agent for Gnome sessions (if you start sugar emulator from Gnome Desktop Environment).

Important notes for XO users:
Some XO images might mount /var/cache/yum to the tmpfs. With this limited cache capacity, it will be mostly impossible to install anything of large size from the Fedora repositories. To work around this limitation, become a root user and enter the umount /var/cache/yum command in the Terminal activity or a console. To persist this change for subsequent boots, remove the corresponding line from the /etc/fstab file.

Fedora specific instructions:

sudo yum install gnome-packagekit

Debian and Ubuntu specific instructons:

sudo apt-get install packagekit-gnome

After installing PackageKit, you need to restart the DBus system bus. The easiest way is to just restart the machine.

Install

Enter in Terminal activity, or any other terminal:

wget http://download.sugarlabs.org/sweets/sweets/installer.sh
sh installer.sh

Relogin from X session to take into account the new PATH environment variable value.

Besides, sweets might be run from the sources.

Upgrade

Enter in Terminal activity, or any other terminal:

sweets upgrade

Usage

Read the Sweets Glossary to understand the basic concept (and overview of the bigger picture). The rest of the text will operate with the following terms:

• SWEET, the full interface URL, like http://sweets.sugarlabs.org/sdk/sugar, or the short one, like sdk/sugar;
• COMMAND, sweet's command that indicates how to run a particular sweet; by default, sweets have only the run command, but it is possible to have several commands;
• VERSION, sweet's version

See the Sugar via Sweets section for real examples of how to use Sweets to run Sugar Shell.

Launch

To launch a sweet with verbatim passing of optional ARGUMENTS:

sweets <SWEET> [<ARGUMENTS>]

Sometimes sweets support several launching commands; it is possible to specify one during the launch:

sweets <SWEET>:<COMMAND>

To run a particular, but not the latest, version:

sweets <SWEET> =|>=|<= <VERSION>

To get the full list of available versions:

sweets status <SWEET> -v

To get information, e.g., a list of supported commands, about a sweet:

sweets show <SWEET>

Troubleshooting

After getting any unpredictable Sweets behaviour, read the following notes.

Keep feeds up-to-date

Feeds are being updated from time to time. After experiencing any problems, and for refreshing the local feeds cache, it will be useful to re-download feeds. Use, once, the -R command line argument for the launch command (make sure that -R goes before the SWEET, because using it afterwards will cause passing it as a SWEET's argument):

sweets -R <SWEET>

Analyze dependencies tree

If sweets can't find a proper implementation, see the e lines in the output of:

sweets status <SWEET> -vdd

Keep the system in consistent state

Asking Sweets to launch a sweets might mean installing new packages via PackageKit. In most cases, PackageKit can handle possible issues with native packages and, at worst, will fail as well, in order to stop any further Sweets operations. Nevertheless, it can be useful to keep unbroken native packages.

Search

It is possible to search sweets among locally known ones and those registered on http://sweets.sugarlabs.org (not yet implemented). The search is based on the Xapian search engine. Thus, it is possible to use Xapian's query language.

For command format is:

sweets search <QUERY>

Notice that partial search is enabled. So, the query tele will be treated as tele* to search all words that start from tele.

sweets supports the following search prefixes based on recipe options:

• interface the first interface from the implementations list, e.g., http://sweets.sugarlabs.org/sdk/sugar;
• sweet the first interface from the implementations list in short Sweets notations, e.g., sdk/sugar;
• implement the list of implemented interfaces;
• associate the list of associated interfaces;
• name the short name of a sweet;
• summary sweet's summary;
• description long sweet's description;
• category list of category names;
• license list of licenses;
• type sweet's type, which might be library, application or activity;
• keep if activity, that a sweet is representing, is favorited;
• tags the list of sweet's tags;
• mime_types the list of activity MIME types, that a sweet is representing or supports.

So, it is possible to search only among particular sweet attributes, like name:telepathy to search only among particular sweet names.

sweets support additional notation for exact searching in the form of prefix:=string. For example the query name:=sugar will find sweets only with exactly sugar as a name and omit names like sugar-base. If the search string contains spaces, wrap it within double quotes, name:="Sugar Commander". Note, wildcards do not work in the exact search case where asterisks will be treated literally.

Sugar via Sweets

To try Sweets in practice, run several Sugar versions. On the Sweets level, there are not any restrictions to using Sweets on any GNU/Linux distribution. Successful usage depends only on the presence of PackageKit and the quality of the sweet packages (sweets). For now, sugar sweets are well aware of Fedora, Debian/Ubuntu, and Gentoo package names and not so well aware of openSUSE and Mandriva. Sugar sweets launchs were tested on some recent Fedora and Ubuntu releases. The quality of other GNU/Linux distribution support depends only on how often Sweets is used on these distributions and the reporting of problems by the community.

Note, Sugar Shell does not start the authentication agent, and preparing sugar to start can be processed only in a Desktop Environment, e.g., Gnome (or launch authentication agent manually).

There are two sweets for Glucose:

• sdk/sugar, for pristine Glucose;
• dextrose/sugar, for Glucose with Dextrose patches applied.

To see what Glucose versions these sweets provide, type in a terminal:

 sweets status sdk/sugar -v

To launch a recent stable Sugar version in emulator mode, type in a terminal:

sweets sdk/sugar:emulator

By default, the most recent stable version will be used. To run a particular version, execute with additional arguments:

sweets sdk/sugar:emulator = 0.88

For now, since there is no Sweets support in the Shell to run activities as sweets, Glucose sweets contain Fructose and Sugar Platform dependencies as suggested ones. To run Sugar with injection of all suggested dependencies, use the -S|--force-suggested command-line argument:

sweets -S sdk/sugar:emulator

If you need to develop Sugar, see Sweets Packaging guide's instructions.

Sugar sweet from X sessions

To start Sugar in the session mode, i.e., not from Xephyr, it will be useful to add a new X session. Place sweets invocation into your ~/.xsession file:

PATH=$HOME/.local/bin:$PATH
sweets sdk/sugar

and create a /usr/share/xsessions/sweets.desktop desktop file:

[Desktop Entry]
Encoding=UTF-8
Name=Sweets
GenericName=Sweets
Exec=/etc/X11/Xsession
Type=Application

After getting a login screen, Sweets session should be present in the sessions list.

Current limitations

• For now, sweets knows only enough about the glucose dependencies to install them from native packages in Debian, Ubuntu, Fedora, Mandriva, openSUSE, and Gentoo.
• Activities can't reuse sweets benefits.

Feedback

• Submit your bug report or feature request.
• Subscribe to the sugar-devel mailing list and email with the subject prefixed with [SWEETS].
• Ask your question on IRC channels, #sugar (not logged) or #sugar-newbies (logged).