Platform Team/Package Management System/1.0/Notes

Retrospection

It is mostly 2 years passed after the time when a meeting, between several Zero Install and Sugar people, happened on #sugar-meeting IRC channel. The meeting was organized by Michael Stone (if I'm wrong, he will correct me) to exchange knowledge and to learn whether Zero Install might be a good fit for use in Sugar activity installation. Thomas Leonard wrote a summary and Michael Stone forwarded it to sugar-devel mailing list.

The idea of using Zero Install in Sugar ecosystem passed several mutations and, eventually, it seems to be that core ideas were settled down and ready to be presented widely in Sugar community.

The pillars

For learning by doing

The one of the core ideas behind Sugar is learning by doing. It is critical to have the tool that will well support doing metaphor, doing not only within regular project teams but also by individuals who tweak the software in the process of learning. But not the least option is sharing results of experiments. Sweets is intended to make both aspects less annoying using the Zero Install system.

To not reinvent the wheels

It will be useful to let people in Sugar community to be concentrated only on software they are developing and reuse existing efforts of GNU/Linux distributions as underliing dependencies for developing software. The PackageKit project gives such possibility.

Infrastructure does matter

The core difference of the final approach with previous evolutions is the idea that successful model should cover the full lifetime cycle of software, from developing by creators to using by the community. Another project, the Open Build System, was chosen for that.

What is Sweets

So, Sweets is a Package Management System based on Zero Install, a decentralized cross-distribution software installation system. It is intended to distribute various software projects created in the Sugar ecosystem, such as libraries, sugar itself, and sugar activities.

This new distribution method is initiated assuming that:

• The method to share software projects should to be as convenient as possible.
• It is important to stimulate users into becoming doers, to modify existing activities, and to share the results of their experiments with other people, i.e., a distribution method should handle different variants of the same project.
• This distribution method is not intended to be the only one, but is targeted more towards direct distribution—from software creators to software users.

The purpose is to create a new distribution method instead of reusing:

1. .xo bundles
   • Work smoothly only for pure python activities, and only if all (and the same) dependencies are installed on all systems. They stop working smoothly if activities use non-standard dependencies or contain binaries.
   • But, are not effective in supporting the use of multiple versions of software, e.g., the results of experiments (the work) of different doers, simultaneously. Users must manually handle the variety of activity versions, e.g., sort out all the local bundles or directories in ~/Activities.
2. native packages
   • Not the shortest way to connect developers with users.
   • In most cases, they don't support multiple versions of the same project.
   • They don't work at all for sharing results of experiments.

At the same time, existing distribution methods are reused in Sweets:

1. .xo bundles is a subset of the Sweets workflow
   • It is possible to bundle an entire directory as a sweet project to use it as a regular .xo file.
2. native packages
   • Sweets is not intended to create one more GNU/Linux distribution. It distributes only projects that people create within the Sugar community; all other software, i.e., dependencies, will be reused from native packages.
   • For cases like Sugar deployments, using the more centralized, regular repositories (third party or official GNU/Linux distributions with native packages) makes more sense. These native packages of Sugar software will be included in Sweets, as well. When people start using Sweets on top of these Sugar distributions, they will have the chance to choose between natively packaged Sugar components and components that came directly from software creators.
   • It is possible, when there is a need, to automatically package sweets into native packages. See Sweets Distribution, for example.

See the Glossary to learn more.

In this release

This is the initial release and have some critical, for Sugar, points missed, e.g., GUI to launch activities using Sweets. The major point for this release is exposing the fact that basic ideas and core implementation is mature enough to make Sweets useful in some workflows and to involve more people to Sweets and Sweets related projects developing, e.g., a la Ubuntu AppCenter for Sugar.

Getting the release

The details instructions can be found in Sweets Usage guide.

First, install PackageKit package with a packages for integration with Desktop Environment you are using, e.g., gnome-packagekit for Gnome. It is important to install exactly integration package to have an authentication agent that depends on particular Desktop Environment. After installation, it might require to relogin from the Desktop Environment session.

Download and run Sweets installer:

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

Relogin from the Desktop Environment session to take into account the new PATH environment variable value that installer will set.

Try the release

To try Sweets on practice, run several Sugar versions. On the Sweets level, there are no any restrictions to use Sweets on any GNU/Linux distribution. The successful usage depends only on the PackageKit presence and the quality of sweet packages (sweets). For now, sugar sweets are well aware about Fedora, Debian/Ubuntu and Gentoo package names and not so well about openSUSE and Mandriva. Sugar sweets launch were tested on some recent Fedora and Ubuntu releases. The quality of other GNU/Linux distributions support depends only on how often Sweets will be used on these distributions.

Note, Sugar Shell does not start authentication agent and preparing sugar start can be processed only in Desktop Environment, e.g., Gnome. To launch recent stable Sugar version in emulator mode, type in a terminal:

sweets sdk/sugar:emulator

To run particular version:

sweets sdk/sugar:emulator = 0.88

After that, it is possible to run Sugar via sweets from the X session.

Further reading

• Sweets home page.
• Sweets Usage - A guide to know how to launch software using Sweets.
• Sweets Packaging - A guide to know how to make your software accessible via Sweets.
• Infrastructure Map - An overview of the Sweets software world.

Looking forward

The next minor, 1.1, release should:

• provide Activity Library activities via Zero Install,
• support search among remote sweets on a client side,
• Initial GUI for browsing local and remote sweets.

Credits

• People who pointed Zero Install out and organized the meeting between Zero Install and Sugar people, Michael Stone.
• Zero Install development team to take care about reviewing the code that was introduced by Sugar workflow needs.
• People who pointed Open Build System out, Jigish Gohil and David Van Assche.
• People who initially tested Sweets and replied with useful feedback, Michael Stone, Rafael Ortiz, Sebastian Silva.
• The Infrastructure Team for their help with setting up services required for Sweets infra.
• The Wiki Team for continuous polishing Sweets wiki pages.
• Activity Central for supporting during the work on 1.0 release final phase.