openSUSE Conference 2017: OBS <B AppImage

Providing desktop applications to multiple Linux-based target systems (distributions) can be cumbersome. Whereas upstream application authors have always had the possibility to offer downloads for Windows and macOS, distributing packages for Linux has traditionally required a lot of additional duplicated effort from maintainers, and does not scale well beyond the core set of applications that are part of the distributions.

Lately, application bundle formats like AppImage, Flatpak, and Snap have gained popularity in the Linux world, with Linux Torvalds calling AppImage "just great" and users appreciating the ease of the "one app = one file" concept.

Providing an application in AppImage format can have many advantages:
- Just one format for many major distributions like openSUSE, Ubuntu, Fedora, CentOS, Debian, and others
- Super simple for users: just download one file, make it executable, and run
- No unpacking or installation necessary
- No root needed
- No system libraries changed
- Works out of the box, no installation of runtimes needed
- Optional desktop integration with `appimaged`
- Optional binary delta updates (only download the bytes that have changed between builds)
- GPG signatures (inside the file)
- Works on Live ISOs and when booting into multiple different distributions

On the flipside, it has been argued that distributing application bundles places additional burden on upstream application authors, who now also need to keep the bundled libraries up-to-date. Tools used by distributions can greatly mitigate this, by ensuring reproducible, up-to-date builds from trusted sources.

In this talk, Open Build Service lead developer Adrian Schröter and AppImage lead developer Simon Peter illustrate the challenges around providing quality application bundles and how they can be solved by using proven distribution methodologies such as those provided by the Open Build Service.

Transcript

1. OBS AppImage openSUSE Conference May 27, 2017 Simon Peter AppImage Adrian Schröter Open Build Service Portable cross-distro application bundles for the Linux desktop
2. THE PROBLEM
3. "As a developer, I want to reach users with minimal effort"
4. .exe .dmg ?
5. Approach #1 OBS
6. „Let‘s take the distribution approach and scale it“
7. A system to build distributions in a controlled way Allow application authors to package applications for all major distributions CENTRAL IDEA
8. Source (from User) Base Binaries (from OBS) OBS checks sources and binares. And may build the source. Published Binaries
9. Authors can get newer applications to mature distributions Application authors can leverage already-packaged dependencies Optimized for base distribution Optional submission to become part of official distribution SOLVES...
10. Still cannot link to a file for Linux Still needs to understand RPM spec files, debian packaging Still need to install applications before using them Still need a package manager, mess around with repositories Still need root rights to install BUT...
11. Approach #2 AppImage
12. „Let‘s take the un-distro approch, like Windows and macOS“
13. .exe .dmg .AppImage
14. Distribution = base system Applications directly from original authors (upstreams) Like Windows and macOS CENTRAL IDEA
15. DEMO
16. EXECUTABLE EXECUTABLE SQUASHFS IMAGE SQUASHFS IMAGE AppImage • One file per app and version
17. EXECUTABLE EXECUTABLE SQUASHFS IMAGE SQUASHFS IMAGE AppImage • Binary • Mounts the image with FUSE when executed
18. EXECUTABLE EXECUTABLE SQUASHFS IMAGE SQUASHFS IMAGE AppImage • Bundle app and everything that is not part of all target systems: icons, i18n, Qt 5, KF5,… • Built on host that as old as the oldest target systems
19. MORE • Binary delta updates using AppImageUpdate – only download what has changed • Sandboxing using, e.g., Firejail • Optional appimaged daemon for desktop integration (menus, icons, MIME types, updates,...)
20. Works for all common Linux distributions Run the latest applications on mature (e.g., enterprise) OSes One app = one file Super simple for users: just download one AppImage file, make it executable, and run No unpacking or installation necessary SOLVES...
21. No root needed No system libraries changed Works out of the box, no installation of runtimes needed Works on Live ISOs, university lab computers,... Can use the same AppImages when dual-booting multiple distributions SOLVES...
22. „This is just very cool.“ https://plus.google.com/+LinusTorvalds/posts/WyrATKUnmrS
23. Krita OFFICIAL APPIMAGES Microsoft PowerShell KDevelop Scribus OpenShot digiKam JetBrains Toolbox MuseScore Kdenlive Subsurface ImagePlay Drawpile ...hundreds more Avidemux https://github.com/probonopd/AppImageKit/wiki/AppImages
24. BUT... FOSDEM 2017
25. Author needs a trusted, reliable, auditable build system Author needs to track security updates of dependencies Author needs to ensure licensing compliance BUT...
27. BETTER TOGETHER
28. OBS AppImage
29. OBS: trusted, reliable, auditable build system that tracks security updates of dependencies, ensures licensing compliance, and hosts build products AppImage: simple bundle format that allows upstream application authors to reach Linux users easily An ideal match! OBS APPIMAGE
30. DEMO
31. Packaging workshop this afternoon: let‘s take your application and package it as an AppImage on OBS Not signed up? Don‘t worry: „Hello world“ at https://build.opensuse.org/package/show/home:probono/QtQuickApp Instructions on https://github.com/probonopd/AppImageKit/wiki/Using-Open-Build-Service OBS APPIMAGE
32. appimage.org #AppImage build.opensuse.org #opensuse-buildservice
33. BACKUP
34. "As a tester, I want to run multiple builds without messing up my system.“
35. "As a user, I want to download an application from the original author and run it, now!“
36. mkdir ­p leafpad/leafpad.AppDir && cd leafpad # Get existing binary wget ­c „http://.../leafpad_0.8.17­2_amd64.deb“ # Turn into an AppDir cd leafpad.AppDir dpkg ­x ../leafpad_*.deb . cp ./usr/share/icons/hicolor/scalable/apps/leafpad.svg . cp ./usr/share/applications/leafpad.desktop . wget ­c https://.../AppRun chmod a+x AppRun cd .. # Package as an AppImage wget ­c https://.../appimagetool.AppImage chmod a+x ppimagetool.AppImage ./appimagetool.AppImageleafpad.AppDir/ HELLO WORLD,…
37. …MORE LIKE THIS # Build on an „old enough“ build system (for which recent compilers and build tools exist, e.g., CentOS 6.x) # Make sure it is relocatable (no hardcoded „/usr“); otherwise patch it # Turn into an AppDir ... chmod a+x AppRun # Bundle any libraries that might not be there in a recent enough version # on each target system # Package the AppDir as an AppImage ... ./appimagetool.AppImage leafpad.AppDir ./Leafpad­x86_64.AppImage # Test on each target system ­ really! (I use Live ISOs)
38. CONTINUOUS APPIMAGE WORKFLOW 2 Push commit to GitHub 1 Prepare build sys- tem, e.g., CentOS 6 with Qt5,… 3 Build and package as an AppImage 4 Upload to, e.g., Bintray, GitHub Releases 5 Post download link on Project homepage