Fedora, GNOME, Linux

Flathub Experience: Adding an App

Flathub is a new distribution channel for Linux desktop apps. Truly distro-agnostic, unifying across abundance of Linux distributions. I was planning for a long time to add an application to Flathub and see what the experience is, especially compared to traditional distro packaging (I’m a Fedora packager). And I finally got to it this last week.


In Fedora I maintain PhotoQt, a very fast image viewer with very unorthodox UI. Its developer is very responsive and open to feedback. Already back in 2016 I suggested he provides PhotoQt as a flatpak. He did so and found making a flatpak really easy. However it was in the time before Flathub, so he had to host its own repo.

Last week I was notified about a new release of PhotoQt, so I prepared updates for Fedora and noticed that the Flatpak support became “Coming soon” again. So I was like “hey, let’s get it back and to Flathub”. I picked up the two-year-old flatpak manifest, and started rewriting it to successfully build with the latest Flatpak and meet Flathub requirements.

First I updated dependencies. You add dependencies to the manifest in a pretty elegant way, but what’s really time consuming is getting checksums of official archives. Most projects don’t offer them at all, so you have to download the archive and generate it yourself. And you have to do it with every update of that dependency. I’d love to see some repository of modules. Many apps share the same dependencies, so why to do the same work again and again with every manifest?

Need to bundle the latest LibRaw? Go to the repository and pick the module info for your manifest:

"name": "libraw",
"cmake": false,
"builddir": true,
"sources": [ { "type": "archive", "url": "https://www.libraw.org/data/LibRaw-0.18.8.tar.gz", "sha256":"56aca4fd97038923d57d2d17d90aa11d827f1f3d3f1d97e9f5a0d52ff87420e2" } ]

And on the top of such a repo you can actually build a really nice tooling. You can let the authors of apps add dependencies simply by picking them from the list and you can generate the starting manifest for them. And you could also check for dependency updates for them. LibRaw has a new version, wanna bundle it, and see how your app builds with it? And the LibRaw module section of your manifest would be replaced by the new one and a build triggered.

Of course such a repo of modules would have to be curated because one could easily sneak in a malicious module. But it would make writing manifests even easier.

Besides updating dependencies I also had to change the required runtime. Back in 2016 KDE only had a testing runtime without any versioning. Flathub now includes KDE runtime 5.10, so I used it. PhotoQt also uses “photoqt” in all file names and Flatpak/Flathub now requires it in the reverse-DNS format: org.qt.photoqt. Fortunately flatpak-builder can rename it for you, you just need to state it in the manifest:

"rename-desktop-file": "photoqt.desktop",
"rename-appdata-file": "photoqt.appdata.xml",
"rename-icon": "photoqt",

Once I was done with the manifest, I looked at the appdata file. PhotoQt has it in a pretty good shape. It was submitted by me when I packaged it for Fedora. But there were still a couple of things missing which are required by Flathub: OASR and release info. So I added it.

I proposed all the changes upstream and at this point PhotoQt was pretty much ready for submitting to Flathub. I never intended to maintain PhotoQt in Flathub myself. There should be a direct line between the app author and users, so apps should be maintained by app authors if possible. I knew that upstream was interested in adding PhotoQt to Flathub, so I contacted the upstream maintainer and asked him whether he wanted to pick it up and go through the Flathub review process himself or whether I should do it and then hand over the maintainership to him. He preferred the former.

The review was pretty quick and it only took 2 days between submitting the app and accepting it to Flathub. There were three minor issues: 1. the reviewer asked if it’s really necessary to give the app access to the whole host, 2. app-id didn’t match the app name in the manifest (case sensitivity), 3. by copy-pasting I added some spaces which broke the appdata file and of course I was too lazy to run validation before submitting it.

And that was it. Now PhotoQt is available in Flathub. I don’t remember how much time exactly it took me to get PhotoQt to Fedora, but I think it was definitely more and also the spec file is more complex than the flatpak manifest although I prefer the format of spec files to json.

Is not your favorite app available in Flathub? Just go ahead, flatpak it, and then talk to upstream, and try to hand the maintainership over to them.

Fedora, Linux

Flathub, Snap, Fedora: what is more up-to-date?

Yesterday I wondered how Flathub and Snap are doing in terms of proving up-to-date applications and how they compare to Fedora, a traditional and quite progressive Linux distribution.

The comparison is not extremely scientific. I picked (pretty much randomly) 16 apps which are in all three sources, looked up the available version and when it was updated. This subset is not very large. Flathub tends to have popular open source applications well known from Linux distributions. Snap lacks many of these, but has quite a few apps outside the traditional Linux desktop world. And at last Fedora doesn’t have many multimedia apps which include patent-protected codecs (VLC, Kdenlive, MPV,…).

To find out the app version and last update date I relied on Github repositories for Flathub, on uApp explorer for Snap, and on Fedora packages app for Fedora (27).

Looking at the table, you can see that the differences are not big. Flathub generally offers the most up-to-date apps having the latest versions of apps in the list except for missing one minor update for Eye of GNOME, it was also usually the first one to offer it.

The results of Fedora are pretty surprising to me. One of the biggest advantages of Flatpak and Snap they claim they have over traditional Linux distributions is that they ship the latest and greatest, but apparently at least in desktop apps Fedora is not behind and offers the latest versions as well (with two exceptions in this list) and often very close behind or sometimes even before the two competitors.

Of course a distribution model like Flatpak still keeps other advantages (and also disadvantages): sandboxing, you can run it on older distributions (e.g. RHEL 7) etc., but if you’re only after the latest versions Flathub and Snap don’t give you a big advantage over Fedora repositories. And if the Fedora Project offers a Flatpak repository built from Fedora packages as we plan, it can actually be a hit because it will be able to offer up-to-date applications and in a much larger number than current Flathub or Snap Store.

App Flathub Snap Fedora
Darktable 2.4.0, Dec 24 2.2.5, Oct 25 2.4.0, Jan 1
Blender 2.79, Sept 26 2.79, Sept 11 2.79, Sept 30
Corebird 1.7.3, Nov 19 1.7.3, Nov 20 1.7.3, Nov 28
GnuCach 2.6.19, Jan 5 2.6.19, Dec 18 2.6.18, Oct 30
Inkscape 0.92.2, Aug 9 0.92.2, Aug 19 0.92.2, Oct 1
LibreOffice 5.4.4, Dec 20, Dec 1, Dec 19
Nextcloud client 2.3.3, Nov 24 2.3.3, Dec 11 2.3.3, Oct 5
Picard 1.4.2, Sept 27 1.4.2, Oct 7 1.3.2, Jul 14
GNOME Calendar 3.26.2, Oct 5 3.26.0, Sept 22 3.26.2, Oct 11
Evince 3.26.0, Nov 9 3.26.0, Nov 29 3.26.0, Sept 18
Eye of GNOME 3.26.1, Nov 7 3.26.2, Nov 29 3.26.2, Nov 15
gedit 3.22.1, Jul 31 3.22.1, Nov 29 3.22.1, Aug 3
Glade 3.20.2, Dec 15 3.20.0, Nov 29 3.20.2, Dec 10
GNOME Characters 3.26.2, Nov 7 3.26.2, Nov 29 3.26.2, Nov 11
GIMP 2.8.22, Oct 17 2.8.22, Dec 11 2.8.22, Nov 11
HexChat 2.2.14, Apr 12 2.2.14, Feb 5 2.2.14, Dec 12 2016
Fedora, Linux

Fedora Media Writer Available in Flathub

Fedora Media Writer is the tool to create live USB flash drives with Fedora. You can also use dd or GNOME Disks, but Fedora Media Writer is the only graphical tool that is tested with Fedora ISOs (please don’t use UNetbootin and such because they really cause faulty Fedora installations).

Fedora Media Writer is available as an RPM package in Fedora repositories and we provide installation files for Windows and macOS. Those are actually offered to users with Windows and macOS as the default download options at getfedora.org. We’ve provided users of other Linux distributions with a flatpak, but it was hosted in its own repo. Recently we managed to get the flatpak to Flathub which many users have already enabled, so now it’s even easier and faster to install.

Snímek z 2017-11-29 13-12-31