Flatpak

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Tango-view-fullscreen.pngThis article or section needs expansion.Tango-view-fullscreen.png

Reason: Need info on building apps. (Discuss in Talk:Flatpak#)

From Wikipedia: "Flatpak, named xdg-app until May 2016, is a system for application virtualization for Linux desktop computer environments."

Installation

Install the flatpak or flatpak-gitAUR package.

If you want to have desktop integration using portals you can install the xdg-desktop-portal-gtk package.

Note: If you want to build flatpaks with flatpak-builder you will need to install the optional dependencies of elfutils and patch.

Managing repositories

Add a repository

To add a remote flatpak repository do:

$ flatpak remote-add name location

where name is the name for the new remote, and location is the path or URL for the repository.

Delete a repository

To delete a remote flatpak repository do:

$ flatpak remote-delete name

where name is the name of the remote repository to be deleted.

Managing runtimes and applications

List available runtimes and applications

To list available runtimes and applications in a remote repository named remote do:

$ flatpak remote-ls remote

Install a runtime or application

To install a runtime or application do:

$ flatpak install remote name

where remote is the name of the remote repository, and name is the name of the application or runtime to install.

List installed runtimes and applications

To list installed runtimes and applications do:

$ flatpak list

Update a runtime or application

To update a runtime or application named name do:

$ flatpak update name

Uninstall a runtime or application

To uninstall a runtime or application named name do:

$ flatpak uninstall name

Adding Flatpak .desktop files to your menu

Flatpak expects window managers to respect the XDG_DATA_DIRS environment variable to discover applications. This may require restarting the session or the launcher may not support this. In such a case where you can edit the list of directories scanned, add these to it:

~/.local/share/flatpak/exports/applications
/var/lib/flatpak/exports/applications

This is known to be necessary in Awesome.

Creating a custom base runtime

Tango-view-fullscreen.pngThis article or section needs expansion.Tango-view-fullscreen.png

Reason: This can certainly be improved. It also has problems with D-Bus for GNOME apps. (Discuss in Talk:Flatpak#)
Warning: If you want to release your software to the public as a Flatpak, an Arch-based runtime is unsuitable. In this case, you will want to follow official documentation to integrate your software into the proper Flatpak ecosystem using the common runtimes.
Note: You may want to use an untrusted, unprivileged user account for bundling untrusted software because the software is not sandboxed during app and runtime creation.
Note: When distributing bundles to others, you may be legally obliged to provide the source code of some of the bundled software upon request. You may want to use ABS to build these packages from source.

You can create a custom Arch-based base runtime and base SDK for Flatpak using pacman. You can then use it for building and packaging applications. This is an alternative for personal use to the default org.freedesktop.BasePlatform and org.freedesktop.BaseSdk runtimes.

In addition to flatpak, you need to have installed fakeroot and for pacman hooks support also fakechroot.

First, start by creating a directory for building the runtime and possibly applications.

$ mkdir myflatpakbuilddir
$ cd myflatpakbuilddir

You can then prepare a directory for building the runtime base platform. The files subdirectory will contain what will later be the /usr directory in the sandbox. Therefore you will need to create symbolic links so the default /usr/share etc. from Arch can still be accessed at the usual path.

$ mkdir -p myruntime/files/var/lib/pacman
$ touch myruntime/files/.ref
$ ln -s /usr/usr/share myruntime/files/share
$ ln -s /usr/usr/include myruntime/files/include
$ ln -s /usr/usr/local myruntime/files/local

Make your host OS fonts available to the Arch runtime:

$ mkdir -p myruntime/files/usr/share/fonts
$ ln -s /run/host/fonts myruntime/files/usr/share/fonts/flatpakhostfonts

You need and may want to adapt your pacman.conf before installing packages to the runtime. Copy /etc/pacman.conf to your build directory and then make the following changes:

  • Remove the CheckSpace option so pacman will not complain about errors finding the root filesystem for checking disk space.
  • Remove any undesired custom repositories and IgnorePkg, IgnoreGroup, NoUpgrade and NoExtract settings that are needed only for the host system.

Now install the packages for the runtime.

$ fakechroot fakeroot pacman -Syu --root myruntime/files --dbpath myruntime/files/var/lib/pacman --config pacman.conf base
$ mv pacman.conf myruntime/files/etc/pacman.conf

Set up the locales to be used by editing myruntime/files/etc/locale.gen. Then regenerate the runtime’s locales.

$ fakechroot chroot myruntime/files locale-gen

The base SDK can be created from the base runtime with added applications needed for building packages and running pacman.

$ cp -r myruntime mysdk
$ fakechroot fakeroot pacman -S --root mysdk/files --dbpath mysdk/files/var/lib/pacman --config mysdk/files/etc/pacman.conf base-devel fakeroot fakechroot --needed

Insert metadata about runtime and SDK.

myruntime/metadata
[Runtime]
name=org.mydomain.BasePlatform
runtime=org.mydomain.BasePlatform/x86_64/2016-06-26
sdk=org.mydomain.BaseSdk/x86_64/2016-06-26
mysdk/metadata
[Runtime]
name=org.mydomain.BaseSdk
runtime=org.mydomain.BasePlatform/x86_64/2016-06-26
sdk=org.mydomain.BaseSdk/x86_64/2016-06-26

Add base runtime and SDK to a local repository in the current directory. You may want to give them appropriate commit messages such as “My Arch base runtime” and “My Arch base SDK”.

$ ostree init --mode archive-z2 --repo=.
$ EDITOR="nano -w" ostree commit -b runtime/org.mydomain.BasePlatform/x86_64/2016-06-26 --tree=dir=myruntime
$ EDITOR="nano -w" ostree commit -b runtime/org.mydomain.BaseSdk/x86_64/2016-06-26 --tree=dir=mysdk
$ ostree summary -u

Install the runtime and SDK.

$ flatpak remote-add --user --no-gpg-verify myarchos file://$(pwd)
$ flatpak install --user myarchos org.mydomain.BasePlatform 2016-06-26
$ flatpak install --user myarchos org.mydomain.BaseSdk 2016-06-26

Creating apps with pacman

As an alternative to building applications the usual way, we can use pacman to create a containerized version of the regular Arch packages. Note that /usr is read-only when creating apps, so we can not use Arch’s packages when building an app. To create a real app with pacman, we can either

  • use pacman to create a runtime containing all dependencies
  • and compile the app ourselves as usual or perhaps using pacman with a custom PKGBUILD tailored to Flatpak which uses --prefix=/app for the configure script,

or we can

  • use pacman to create a runtime containing the app installed with pacman
  • and create a dummy app to launch it.

For doing the latter, first create a runtime using pacman such as this one for gedit. The runtime is first initialized and prepared for use with pacman.

$ flatpak build-init -w geditruntime org.mydomain.geditruntime org.mydomain.BaseSdk org.mydomain.BasePlatform 2016-06-26
$ flatpak build geditruntime sed -i "s/^#Server/Server/g" /etc/pacman.d/mirrorlist
$ flatpak build geditruntime ln -s /usr/var/lib /var/lib
$ flatpak build geditruntime fakeroot pacman-key --init
$ flatpak build geditruntime fakeroot pacman-key --populate archlinux

Then the package is installed. The host’s network connection must be made available to pacman.

$ flatpak build --share=network geditruntime fakechroot fakeroot pacman --root /usr -S gedit

You can test the installation before finishing the runtime (without proper sandboxing).

$ flatpak build --socket=x11 geditruntime gedit

Now finish building the runtime and export it to a new local repository. pacman’s GnuPG keys have permissions that may interfere and need to be removed first.

$ flatpak build geditruntime rm -r /etc/pacman.d/gnupg
$ flatpak build-finish geditruntime
$ sed -i "s/\[Application\]/\[Runtime\]/;s/runtime=org.mydomain.BasePlatform/runtime=org.mydomain.geditruntime/" geditruntime/metadata
$ flatpak build-export -r geditrepo geditruntime

Then create a dummy app.

$ flatpak build-init geditapp org.gnome.gedit org.mydomain.BaseSdk org.mydomain.geditruntime

Now finish the dummy app. You can fine-tune the app’s access permissions when sandboxed by giving additional options when finishing the build. For possible options see the Flatpak documentation and the GNOME manifest files. Alternatively, adapt geditapp/metadata to your needs after finishing the build but before exporting. When the metadata file is complete, export the app to the repository.

$ flatpak build-finish geditapp --socket=x11 [possibly other options] --command=gedit
$ flatpak build-export geditrepo geditapp

Install it along with the runtime.

$ flatpak --user remote-add --no-gpg-verify geditrepo geditrepo
$ flatpak install --user geditrepo org.mydomain.geditruntime
$ flatpak install --user geditrepo org.gnome.gedit
$ flatpak run org.gnome.gedit

See also