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Platform Team/Package Management System

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Revision as of 23:01, 26 June 2010 by Alsroot (talk | contribs) (→‎How it works at a glance)



Zero Sugar Distribution

Zero Sugar provides a method that is transparent for users and convenient for doers to deploy software across varying platforms as well as across Sugar releases. Zero Sugar is mainly targeted to support a direct doer-to-user interaction model, i.e., shortcut the chain of transfer of doer-to-distributor-to-user (still, Zero Sugar could be beneficial for distributors, since it unifies the deployment workflow).

Benefits

How Zero Sugar might be useful depending upon your point of view:

Users

Users can run Sugar effortlessly in multiple environments (machine architectures, GNU/Linux distributions, etc.). And since Sugar also stimulates users to be doers, there can be tons of handmade software in the field (mostly duplicates and reinvented wheels, but this is the nature of learning with Sugar—one tries some software, realizes some missing or additional feature, modifies or mimics some code, learns something new, and eventually produces a new creation). It is becoming critical to provide an easy and robust launching scheme for all these pieces of code, without writing long HOWTOs somewhere on a wiki, like "Please, if you are on Ubuntu, install these packages before starting my activity...".

Relying only on a particular distributor, i.e., using activities only from one distributor's channel, makes Sugar less useful or universal. Zero Sugar provides the most convenient and direct deployment method possible between the author of a piece of code and its users.

Doers

Authors of code are always interested in supporting as large an audience of users as possible. And since people can use Sugar in different environments, it is critical to provide an instrument that permits an activity to run on all Sugar platforms. In the case of Python-based activities, the existing practice of just zipping the activity code into .xo files works pretty well. But for arbitrary scripting languages, such as Ruby, that are not part of the Sugar Platform, and for activities that have dependencies that are not included in the Sugar Platform, there is the problem of providing the user with the necessary code.

Zero Sugar tries to solve all the possible issues that prevent activity launching in an heterogeneous Sugar environment.

Also, if you have some development idea in mind, you can start pushing it through the Sucrose release queue to get it into an upcoming (though maybe not the nearest) release. However, since the release process is binary—either your feature is included or not—Zero Sugar offers more flexibility for everyone. For example:

  • some features are of arguable general benefit; Zero Sugar would allow interested end users to efficiently test (and even deploy) such features;
  • some feature are only stable in limited environments; Zero Sugar would allow deployment in limited environments without the risk of destabilizing the rest of Sugar.

Distributors

The Sugar Platform cannot grow endlessly, e.g., installing Sugar from packages should not fetch half of all available packages including several UI toolkits, several programming languages, etc. So, components like Qt or Ruby are (at least at present) not in the Sugar Platform list. But with Zero Sugar, activities could still use such dependencies by installing them from native packaging systems on demand, and without bundling their binaries.

How it works at a glance

Instruments and services that are used within Zero Sugar:

  • 0sugar, the main tool, everything happens via the 0sugar command.
  • 0install decentralized deployment infrastructure.
  • OBS, openSUSE Build Service, build farms and repository of native packages for the GNU/Linux distributions and architectures that OBS supports.
  • PackageKit to install software from native packaging systems.
  • Sugar Labs's resources to host various files.

The process departing point is a spec file which is used by the 0sugar command to accomplish two major tasks:

  • how to build the application and its dependencies,
  • how to deploy the application and its dependencies.

A building step might occur:

  • but, building is not required for scripting languages.
  • on the developer's workstation, to deploy to environments similar to the developer's, or
  • on OBS, to build for the GNU/Linux distributions that OBS supports.

Deployment will happen:

  • via the 0install infrastructure:
    • analogs of the application and its dependencies could be installed from native packaging system, if PackageKit is installed.
    • by downloading from http://download.sugarlabs.org/, if the application was built in the developer's environment,
    • by downloading from OBS repositories, if the application was built on OBS,
  • via native packages, only if the build happened on OBS; users need to follow the regular workflow, for their distributions, to attach to the external OBS repository.

The regular workflow within Zero Sugar will look like:

  • create or modify spec file.
  • if OBS should be used, add additional information to spec file that will be used while interaction with OBS.
  • call 0sugar dist command to create sources distribution files or just distribution files for applications that don't requires compiling.
  • call 0sugar build command, if OBS is not used and application requires compiling.
  • call 0sugar commit command to publish 0nstall information and interact with OBS (if it is enabled).
  • newly created release is accessible via 0isntall or via OBS repositories.

Documentation

Start your exploration beginning with these resources:

See Scalable development model to learn more about the initial intentions for Zero Sugar.

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