The gnome extension

The gnome extension helps with the creation of snaps that use GTK 3, GNOME 42+, and/or GLib.

This is an updated version of the gnome-3-38 extension that will only work with the core22 base snap, built from Ubuntu 22.04 LTS.

Previous Gnome extensions were built to use core18, based on Ubuntu 18.04 LTS and core20, based on Ubuntu 20.04 LTS.

This extension provides many of the components needed for general desktop applications making it useful for a broader set of applications outside of those tailored for the GNOME desktop.

:information_source: Snapcraft extensions enable snap developers to easily incorporate a set of common requirements into a snap. See Snapcraft extensions for further details.

How to use it

This extension currently only works with the core22 base snap (see Base snaps for details). To use it, add extensions: [gnome] to the application definition in your snapcraft.yaml file.

For instance:

        extensions: [gnome]
        command: usr/bin/tali

See GTK3 applications for a comprehensive overview of using extensions with GNOME applications.

Interface connections

The following plugs are provided by the extension and implicitly included in your snapcraft.yaml:

        mount-host-font-cache: false
        interface: content
        target: $SNAP/data-dir/themes
        default-provider: gtk-common-themes
        interface: content
        target: $SNAP/data-dir/icons
        default-provider: gtk-common-themes
        interface: content
        target: $SNAP/data-dir/sounds
        default-provider: gtk-common-themes
        interface: content
        target: $SNAP/gnome-platform
        default-provider: gnome-42-2204

Your app may still need additional plugs, but you can expect the following plugs to be automatically available to your apps as well:

plugs: [ desktop, desktop-legacy, gsettings, opengl, wayland, x11, mount-observe, calendar-service]

See Adding interfaces for more details.

Included packages

The GNOME extension is derived from two separate snaps; a build snap and a platform snap.

The build snap builds compiles libraries from source that are commonly used across GNOME applications. Examples include glib, gtk, and gnome-desktop. These are built to provide newer versions of these packages that exist in the core22 base snap (a subset of the Ubuntu 22.04 archive).

The platform snap takes the build snap and makes all of those libraries available to your snap at build time without needing to include the pieces of the build snap that are unnecessary at runtime (like compilers) in your final snap.

Environment variables

In addition to using the build and platform snaps, the gnome-3-38 extension also sets a collection of environment variables, links, default plugs for the app to use, and a default build-environment for each part in your snap to use.

Build variables

The following “build-environment” section is made available to each part built in your snap.

If you define other build-environment variables, then those will get added to these and the set is used. If you define another value for one of these variables, then the value you’ve defined will be used instead of the value defined within the extension.

-   PATH: /snap/gnome-42-2204-sdk/current/usr/bin${PATH:+:$PATH}
-   XDG_DATA_DIRS: $SNAPCRAFT_STAGE/usr/share:/snap/gnome-42-2204-sdk/current/usr/share:/usr/share${XDG_DATA_DIRS:+:$XDG_DATA_DIRS}
-   LD_LIBRARY_PATH: /snap/gnome-42-2204-sdk/current/lib/$CRAFT_ARCH_TRIPLET:/snap/gnome-42-2204-sdk/current/usr/lib/$CRAFT_ARCH_TRIPLET:/snap/gnome-42-2204-sdk/current/usr/lib:/snap/gnome-42-2204-sdk/current/usr/lib/vala-current:/snap/gnome-42-2204-sdk/current/usr/lib/$CRAFT_ARCH_TRIPLET/pulseaudio${LD_LIBRARY_PATH:+:$LD_LIBRARY_PATH}
-   PKG_CONFIG_PATH: /snap/gnome-42-2204-sdk/current/usr/lib/$CRAFT_ARCH_TRIPLET/pkgconfig:/snap/gnome-42-2204-sdk/current/usr/lib/pkgconfig:/snap/gnome-42-2204-sdk/current/usr/share/pkgconfig${PKG_CONFIG_PATH:+:$PKG_CONFIG_PATH}
-   GETTEXTDATADIRS: /snap/gnome-42-2204-sdk/current/usr/share/gettext-current${GETTEXTDATADIRS:+:$GETTEXTDATADIRS}
-   GDK_PIXBUF_MODULE_FILE: /snap/gnome-42-2204-sdk/current/usr/lib/$CRAFT_ARCH_TRIPLET/gdk-pixbuf-current/loaders.cache
-   ACLOCAL_PATH: /snap/gnome-42-2204-sdk/current/usr/share/aclocal${ACLOCAL_PATH:+:$ACLOCAL_PATH}
-   PYTHONPATH: /snap/gnome-42-2204-sdk/current/usr/lib/python3.10:/snap/gnome-42-2204-sdk/current/usr/lib/python3/dist-packages:/snap/gnome-42-2204-sdk/current/usr/lib/$CRAFT_ARCH_TRIPLET/gobject-introspection${PYTHONPATH:+:$PYTHONPATH}

Runtime variables

The following environment is set when your application is run:

  SNAP_DESKTOP_RUNTIME: $SNAP/gnome-platform

Layouts set

The platform snap’s gjs, webkit2gtk-4.0, and iso-codes are used so they don’t need to be packaged as part of the snap and would greatly inflate the size.

        symlink: $SNAP/usr/lib/$SNAPCRAFT_ARCH_TRIPLET/libgweather-4
        symlink: $SNAP/usr/lib/evolution-data-server
        symlink: $SNAP/usr/bin/gnome-control-center
        bind: $SNAP/gnome-platform/usr/lib/$SNAPCRAFT_ARCH_TRIPLET/webkit2gtk-4.0
        bind: $SNAP/gnome-platform/usr/share/xml/iso-codes
        bind: $SNAP/gnome-platform/usr/share/libdrm

See Snap layouts for further details.

Last updated 1 year, 7 months ago.