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
   

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2. THE PROBLEM
   

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3. "As a developer, I want to reach
   users with minimal effort"
   

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4. .exe .dmg ?
   

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5. Approach #1
   OBS
   

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6. „Let‘s take the distribution
   approach and scale it“
   

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7. A system to build distributions in a
   controlled way
   Allow application authors to package
   applications for all major distributions
   CENTRAL IDEA
   

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8. Source
   (from User)
   Base Binaries
   (from OBS)
   OBS checks
   sources and
   binares. And may
   build the source.
   Published Binaries
   

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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...
   

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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...
    

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11. Approach #2
    AppImage
    

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12. „Let‘s take the un-distro
    approch, like Windows and
    macOS“
    

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13. .exe .dmg .AppImage
    

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14. Distribution = base system
    Applications directly from original
    authors (upstreams)
    Like Windows and macOS
    CENTRAL IDEA
    

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15. DEMO
    

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16. EXECUTABLE
    EXECUTABLE
    SQUASHFS IMAGE
    SQUASHFS IMAGE
    AppImage
    • One file per app
    and version
    

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17. EXECUTABLE
    EXECUTABLE
    SQUASHFS IMAGE
    SQUASHFS IMAGE
    AppImage
    • Binary
    • Mounts the image
    with FUSE when
    executed
    

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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
    

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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,...)
    

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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...
    

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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...
    

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22. „This is just very cool.“
    https://plus.google.com/+LinusTorvalds/posts/WyrATKUnmrS
    

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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
    

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24. BUT...
    FOSDEM 2017
    

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25. Author needs a trusted, reliable, auditable build system
    Author needs to track security updates of dependencies
    Author needs to ensure licensing compliance
    BUT...
    

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27. BETTER
    TOGETHER
    

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28. OBS AppImage
    

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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
    

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30. DEMO
    

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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
    

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32. appimage.org
    #AppImage
    build.opensuse.org
    #opensuse-buildservice
    

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33. BACKUP
    

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34. "As a tester, I want to run
    multiple builds without
    messing up my system.“
    

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35. "As a user, I want to
    download an application
    from the original author
    and run it, now!“
    

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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,…
    

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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)
    

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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
    

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