Platform Team/Guide/Sweets Packaging

Introduction

The purpose of this Guide is describing how to get benefits of Sugar Services for your library/application, simplify support fork flows and let your users(developers) use your code in simple and convenient way.

This guide is about how to package your code to services, if you are looking for method how to install some software from native packages, see Native packages usage guide.

If service is not wrapper for native package and could be used by other developers, please consider possibility to create service page using template.

Detailed description

The result for service development process will be regular 0install files that are placed to subdirectory on http://download.sugarlabs.org/services/ with name which is identity for the service in the rest of 0sugar infrastructure. Service's subdirectory will contain:

runtime.xml, regular 0install feed file which will be used as a runtime dependency
buildtime.xml, regular 0install feed file which will be used as a buildtime dependency
bunch of tarballs with sources and binaries, feed files contain links to these files

Feed files, in addition to several information fields, contain tags that describe implementations of the service(i.e. releases). At the same time, feed file contains implementations for various service versions and the same version could be represented by several implementations:

source implementation in <implementation> tag with attribute arch == *-src, with links to source tarball and instructions how to build it
no arch implementation in <implementation> tag with attribute arch == *-*, which can be used as-is on different platforms e.g. pure python services
one or several binary implementations in <implementation> tags, that contain binaries of the same source implementation but for various architectures(attribute arch)
package implementation in <package-implementation> tag, to reuse native packages, see Native packages usage for more info.

0sugar tool

To start developing services, install injector tool, and 0sugar - main tool to maintain services infrastructure.

0alias 0sugar http://download.sugarlabs.org/services/0sugar/runtime.xml

While working, 0sugar creates dist/ directory in project's root and uses it as a rsynced copy of service's directory on the server. So, you need ssh access to sunjammer server, create ticket for shell.sugarlabs.org category on http://bugs.sugarlabs.org/.

0sugar commands are:

init, create service/ directory and default service.info file
clone, rsync entirely dist/ from the server
dist, create source or any arch tarball/implementation in dist/ directory and tweak dist/feed.xml correspondingly
If there is second option-less argument, it will be treated as a path of tarball to release(e.g. you can create such tarball by make distcheck command for autotools based projects), otherwise 0sugar will tar all project files(and try to avoid temporary files as much as possible)
dist will create
- any arch archive, if build-command field was omitted in service.info
- source archive, if service.info has build-command field
dist_bin, create binary tarball/implementation for current arch in dist/ directory and tweak dist/feed.xml correspondingly
if second argument was passed, it will be treated as a name of service.info section with additional requires fields
push, rsync dist/ to the server
lint, check feed file on the server
will run FeedLint application for http://download.sugarlabs.org/services/ feed

Feed files in dist/ directory could be changed manually but keep in mind that dist* commands will rewrite entries for current service version.

Versioning scheme

There could be two different versioning scheme for services.

Upstream versions

If service is just a wrapper around existed project with its own versioning scheme then there is even no need in any mentioning of versions in service.info file. Particular version will be chosen on every 0sugar dist* command invoking or will be fetched from native packaging systems(if service doesn't provide binaries and only contains information about already well packaged in various GNU/Linux distributions).

Native versions

The rest of services will use scheme:

<version>-<revision>

<version> is a version field from service.info file which is a plain number
<revision> is an auto incremented number which is beeing changed by 0sugar push command (like Subversion revision)

Commands dist and dist_bin rewrite releases with the same version versions and don't remove other releases.

Libraries have also age parameter which is libtool like age version part. age won't be exposed in version string but will be present in feed files and 0sugar will check it while deciding what dependency version should be chosen.

Stability status

One of core differences from Sucrose development process is having not stable "releases" (here, release is a result of ``0sugar push`` command). So, services need stability status. Internally each service release will have one of 0install stability statuses:

stable, final stable release
testing, let interested in testing people, try last changes that are not yet stable
developer, just more extreme version of testing
buggy, already released versions(of any status) could be marked as buggy after a while to force people upgrade to new bugfix version
insecure, extreme version of buggy

0sugar push w/o arguments will push local changes as is. If you want to push with particular stability status, use 0sugar push <status>.

By default all users will use only stable versions and won't upgrade to new versions even if there are stable ones. To force people to upgrade from buggy versions, see bugfix releases workflow.

Development workflows

Service developer can follow one of several step-by-step scenarios:

Activity specific Services HOWTO if your activity uses its own binaries
Binary-less Services HOWTO to make any architecture service e.g. python based
Binary Services HOWTO services that contain binaries
Upstream Services HOWTO if your activity or service uses project which is not part of Sugar Platform, follow this howto to create wrapper around upstream project and just add its name to requires section of .info file
Wrap native packages HOWTO this is a special one, if some project is already well packaged to various GNU/Linux distributions but is not Sugar Platform component, just create "fake" service.

Release workflows

Having only stable releases

All releases of your services will have stable stability status.

when your code is ready to release
0sugar dist* to make bundles
0sugar push stable to rsync bundles to the server
if it was wrong time to release and you want to re-release it, repeat previous steps to rewrite wrong release

Bugfix releases

Services assume simple versioning scheme, if you found bugs in stable version:

either 0sugar push stable release once more(users will not mess this new copy of release with previous ones)
or 0sugar push stable release with incremented version field
if bugs are critical, mark previous release as buggy or insecure to force users upgrade their old releases. If you re-pushed release w/o incrementing version number, you should use revision number

0sugar push {buggy|insecure} {version[-revision]}

Development releases

If you want to test your new version among interested people:

do all steps that are mentioned in previous workflows
but use either testing or developer status for push command
users who interested in testing(enabled testing mode) will get your new development version
you don't have to change version all time for micro releases, 0sugar will implicitly change revision of new pushes and users will download last changes

Tips

Via binding's variables, service's root directory will be accessible for service users, so for python services(for example), better to use subdirectory for service's import modules like Toolkit does - there is toolkit subdirectory in Toolkit's root.

Be careful with machine architecture, especially in making binaries in VMs e.g. XO-1 arch is i586 but built in XO VM, binaries could have i686 thus won't start(0install won't let) on XO-1. Use --arch 0sugar's argument to set targeted architecture explicitly.

Documentation