gstreamer/Multiplatform+deployment+using+Cerbero.markdown

Multiplatform deployment using Cerbero

Cerbero is the build and packaging system used to construct the GStreamer SDK. It uses “recipe” files that indicate how to build particular projects, and on what other projects they depend. Moreover, the built projects can be combined into packages for distribution. These packages are, depending on the target platform, Windows or OS X installers or Linux packages.

To use Cerbero to build and package your application, you just need to add a recipe explaining how to build you application and make it depend on the gstreamer-sdk project. Then Cerbero can take care of building your application and its dependencies and package them all together.

Read Building from source using Cerbero to learn how to install and use Cerbero.

At this point, after reading the Build from source section in Building from source using Cerbero, you should be able to build the GStreamer SDK from source and are ready to create recipe and package files for your application.

In the Cerbero installation directory you will find the cerbero-uninstalled script. Execute it without parameters to see the list of commands it accepts:

./cerbero-uninstalled

Adding a recipe for your application

The first step is to create an empty recipe that you can then tailor to your needs:

./cerbero-uninstalled add-recipe my-app 1.0

This will create an initial recipe file in recipes/my-app.recipe, which contains the smallest necessary recipe. This file is a Python script; set the following attributes to describe your application:

Attribute Name

Description

Required

Example

name

The recipe name.

Yes

name = 'my-app'

version

The software version.

Yes

version = '1.0'

licenses

A list of licenses of the software (see cerbero/enums.py:License for allowed licenses).

Yes

licenses = [License.LGPLv2Plus]

deps

A list of build dependencies of the software as recipe names.

No

deps = ['other', 'recipe', 'names']

platform_deps

Platform specific build dependencies (see cerbero/enums.py:Platform for allowed platforms).

No

*platform_deps = {Platform.LINUX: ['some-recipe'], Platform.WINDOWS:

'another-recipe'

remotes

A dictionary specifying the git remote urls where sources are pulled from.

No

remotes = {'origin': 'git://somewhere'}

commit

The git commit, tag or branch to use, defaulting to "sdk-version".

No

commit = 'my-app-branch'

config_sh

Used to select the configuration script.

No

config_sh = 'autoreconf -fiv && sh ./configure'

configure_options

Additional options that should be passed to the configure script.

No

configure_options = '--enable-something'

use_system_libs

Whether to use system provided libs.

No

use_system_libs = True

btype

The build type (see cerbero/build/build.py:BuildType for allowed build types).

No

btype = BuildType.CUSTOM

stype

The source type (see cerbero/build/source.py:SourceType for allowed source types).

No

stype = SourceType.CUSTOM

files_category

A list of files that should be shipped with packages including this recipe category. See below for more details.

Cerbero comes with some predefined categories that should be used if the files being installed match a category criteria.

The predefined categories are:

libs (for libraries), bins (for binaries), devel (for development files - header, pkgconfig files, etc), python (for python files) and lang (for language files).

Note that for the bins and libs categories there is no need to specify the files extensions as Cerbero will do it for you.

Yes*

files_bins = ['some-binary']

files_libs = ['libsomelib']

*files_devel = ['include/something'] files_python =

'site-packages/some/pythonfile%(pext)s'

files_lang = ['foo']

platform_files_category

Same as files_category but for platform specific files.

No

platform_files_some_category = {Platform.LINUX: ['/some/file']}

* At least one “files” category should be set.

Apart from the attributes listed above, it is also possible to override some Recipe methods. For example the prepare method can be overridden to do anything before the software is built, or the install and post_install methods for overriding what should be done during or after installation. Take a look at the existing recipes in cerbero/recipes for example.

Alternatively, you can pass some options to cerbero-uninstalled so some of these attributes are already set for you. For example:

./cerbero-uninstalled add-recipe --licenses "LGPL" --deps "glib,gtk+" --origin "git://git.my-app.com" --commit "git-commit-to-use" my-app 1.0

See ./cerbero-uninstalled add-recipe -h for help.

As an example, this is the recipe used to build the Snappy media player:

class Recipe(recipe.Recipe):
    name = 'snappy'
    version = '0.2+git'
    licenses = [License.GPLv2Plus]
    config_sh = 'autoreconf -fiv && sh ./configure'
    deps = ['glib', 'gstreamer', 'gst-plugins-base', 'clutter', 'clutter-gst']
    platform_deps = { Platform.LINUX: ['libXtst'] }
    use_system_libs = True
    remotes = {'upstream': 'git://git.gnome.org/snappy'}

    files_bins = ['snappy']
    files_data = ['share/snappy']

    def prepare(self):
        if self.config.target_platform == Platform.LINUX:
            self.configure_options += ' --enable-dbus' 

Cerbero gets the software sources to build from a GIT repository, which is specified via the git_root configuration variable from the Cerbero configuration file (see the "Build from software" section in Installing on Linux) and can be overridden by the remotes attribute inside the recipes (if setting the origin remote). In this case where no “commit” attribute is specified, Cerbero will use the commit named “sdk-0.2+git” from the GIT repository when building Snappy.

Once the recipe is ready, instruct Cerbero to build it:

./cerbero-uninstalled build my-app

Adding a package for you software

To distribute your software with the SDK it is necessary to put it into a package or installer, depending on the target platform. This is done by selecting the files that should be included. To add a package you have to create a package file in cerbero/packages. The package files are Python scripts too and there are already many examples of package files in cerbero/packages.

Now, to create an empty package, do:

./cerbero-uninstalled add-package my-app 1.0

This will create an initial package file in packages/my-app.package.

The following Package attributes are used to describe your package:

Attribute Name

Description

Required

Example

name

The package name.

Yes

name = 'my-app'

shortdesc

A short description of the package.

No

shortdesc = 'some-short-desc'

longdesc

A long description of the package.

No

longdesc = 'Some Longer Description'

codename

The release codename.

No

codename = 'MyAppReleaseName'

vendor

Vendor for this package.

No

vendor = 'MyCompany'

url

The package url

No

url = 'http://www.my-app.com'

version

The package version.

Yes

version = '1.0'

license

The package license (see cerbero/enums.py:License for allowed licenses).

Yes

license = License.LGPLv2Plus

uuid

The package unique id

Yes

uuid = '6cd161c2-4535-411f-8287-e8f6a892f853'

deps

A list of package dependencies as package names.

No

deps = ['other', 'package', 'names']

sys_deps

The system dependencies for this package.

No

sys_deps= {Distro.DEBIAN: ['python']}

files

A list of files included in the runtime package in the form “recipe_name:category1:category2:...”

If the recipe category is omitted, all categories are included.

Yes*

files = ['my-app']

files = ['my-app:category1']

files_devel

A list of files included in the devel package in the form “recipe_name:category1:category2:...”

Yes*

files_devel = ['my-app:category_devel']

platform_files

Same as files but allowing to specify different files for different platforms.

Yes*

*platform_files = {Platform.WINDOWS:

'my-app:windows\_only\_category'

platform_files_devel

Same as files_devel but allowing to specify different files for different platforms.

Yes*

*platform_files_devel = {Platform.WINDOWS:

'my-app:windows\_only\_category\_devel'

* At least one of the “files” attributes should be set.

Alternatively you can also pass some options to cerbero-uninstalled, for example:

./cerbero-uninstalled add-package my-app 1.0 --license "LGPL" --codename MyApp --vendor MyAppVendor --url "http://www.my-app.com" --files=my-app:bins:libs --files-devel=my-app:devel --platform-files=linux:my-app:linux_specific --platform-files-devel=linux:my-app:linux_specific_devel,windows:my-app:windows_specific_devel --deps base-system --includes gstreamer-core

See ./cerbero-uninstalled add-package -h for help.

As an example, this is the package file that is used for packaging the gstreamer-core package:

class Package(package.Package):
    name = 'gstreamer-codecs'
    shortdesc = 'GStreamer codecs'
    version = '2012.5'
    codename = 'Amazon'
    url = "http://www.gstreamer.com"
    license = License.LGPL
    vendor = 'GStreamer Project'
    uuid = '6cd161c2-4535-411f-8287-e8f6a892f853'
    deps = ['gstreamer-core']

    files = ['flac:libs',
            'jasper:libs', 'libkate:libs',
            'libogg:libs', 'schroedinger:libs', 'speex:libs',
            'libtheora:libs', 'libvorbis:libs', 'wavpack:libs', 'libvpx:libs',
            'taglib:libs',
            'gst-plugins-base:codecs', 'gst-plugins-good:codecs',
            'gst-plugins-bad:codecs', 'gst-plugins-ugly:codecs']
    files_devel = ['gst-plugins-base-static:codecs_devel',
            'gst-plugins-good-static:codecs_devel',
            'gst-plugins-bad-static:codecs_devel',
            'gst-plugins-ugly-static:codecs_devel']
    platform_files = {
            Platform.LINUX: ['libdv:libs'],
            Platform.DARWIN: ['libdv:libs']
    } 

At this point you have two main options: you could either have a single package that contains everything your software needs, or depend on a shared version of the SDK.

Having a private version of the SDK

To have a private version of the SDK included in a single package you don't have to add the deps variable to the package file but instead list all files you need in the files variables. If you decide to go this road you must make sure that you use a different prefix than the GStreamer SDK in the Cerbero configuration file, otherwise your package will have file conflicts with the GStreamer SDK.

Having a shared version of the SDK

If you decide to use a shared version of the SDK you can create a package file like the other package files in the GStreamer SDK. Just list all packages you need in the deps variable and put the files your software needs inside the files variables. When building a package this way you must make sure that you use the same prefix and packages_prefix as the ones in your Cerbero configuration file.

Finally, build your package by using:

./cerbero-uninstalled package your-package 

Where your-package is the name of the .package file that you created in the packages directory. This command will build your software and all its dependencies, and then make individual packages for them (both the dependencies and your software). The resulting files will be in the current working directory.