Fedora, GNOME, Linux

Fedora at LinuxDays 2018 in Prague

LinuxDays, the biggest Linux event in the Czech Republic, took place at the Faculty of Information Technology of Czech Technical University in Prague. The number of registered attendees was a bit lower this year, it could be caused by municipality and senate elections happening on Fri and Sat, but the number got almost to the 1300 mark anyway.

Besides a busy schedule of talks and workshops the conference also has a pretty large booth area and as every year I organized the Fedora one. I drove by car to Prague with Carlos Soriano and Felipe Borges from the Red Hat desktop team on Saturday morning and we were joined by František Zatloukal (Fedora QA) at the booth.

linuxdays-fedora
František and me at the booth.

Our focus for this year was Silverblue and modularity. I prepared one laptop with an external monitor to showcase Silverblue, the atomic version of Fedora Workstation. I must say that the interest of people in Silverblue surprised me. There were even some coming next day saying: “It sounded so cool yesterday and I couldn’t resist and install it when I got home and played with it in the night…” With Silverblue comes distribution of applications in Flatpak and there was a lot of user interest in this direction as well.

DSC_0563
Reasons to use Fedora.

I was hoping for more interest in modularity, but people don’t seem to be so aware of it. It doesn’t have the same reach outside the Fedora Project as Flatpak does, it’s not so easy to explain its benefits and use cases. We as a project have to do a better job selling it.

The highlight of Saturday was when one of the sysadmins at National Library of Technology, which is on the same campus, took us to the library to show us public computers where they run Fedora Workstation. It’s 120 computers with over 1000 users (in the last 90 days). Those computers serve a very diverse group of users, from elderly people to computer science students. And they have received very few complaints since they switched from Windows to Fedora. Also they’ve hit almost no problems as sysadmins. They only mentioned one corner case bug in GDM which we promised to look into.

linuxdays-ntk
Carlos and Felipe checking out Fedora in the library.

It was also interesting to see the setup. They authenticate users against AD using the SSSD client, mount /home from a remote server using NFS. They enable several GNOME Shell extensions by default: AlternateTab (because of Windows users), Places (to show the Places menu next to Activities)… They also created one custom extension that replaces the “Power Off” button with “Log Out” button in the user menu because users are not supposed to power the computers off. They also create very useful stats of application usage based on “recently-used” XML files that GNOME creates to generate the menu of frequently used applications. All computers are administrated using Ansible scripts.

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Default wallpaper with instructions.

The only talk I attended on Saturday was “Why and How I Switched to Flatpak for App Distribution and Development in Sandbox” by Jiří Janoušek who develops Nuvola apps. It was an interesting talk and due to his experience developing and distributing apps on Linux Jiří was able to name and describe all the problems with app distribution on Linux and why Flatpak helps here.

On Sunday, we organized a workshop to teach to build flatpaks. It was the only disappointment of the weekend. Only 3 ppl showed up and none of them didn’t really need to learn to build flatpaks. We’ll have the same workshop at OpenAlt in Brno and if the attendance is also low, we’ll know that workshop primarily for app developers is not a good fit for such conferences.
But it was not a complete waste of time, we discussed some questions around Flatpak and worked on flatpaking applications. The result is GNOME Recorder already available in Flathub and Datovka in the review process.

The event is also a great opportunity to talk to many people from the Czech community and other global FLOSS projects. SUSE has traditionally a lot of people there, there was Xfce, FFMPEG, FreeBSD, Vim, LibreOffice…

 

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Fedora, GNOME, Linux

Story of GNOME Shell Extensions

A long time ago (exactly 10 years ago) it was decided that the the shell for GNOME would be written in JavaScript. GNOME 3 was still looking for its new face, a lot of UI experimentation was taking place, and JavaScript looked like the best candidate for it. Moreover it was a popular language on the web, so barriers to entry for new contributors would be significantly lowered.

When you have the shell written in JavaScript you can very easily patch it and alter its look and behaviour. And that’s what people started doing. Upstream was not very keen to officially support extensions due to their nature: they’re just hot patching the GNOME Shell code. They have virtually unlimited possibilities in changing look and behaviour, but also in introducing instability.

But tweaking the shell became really popular. Why wouldn’t it? You can tweak your desktop by simply clicking buttons in your browser. No recompilations, no restarts. So extensions.gnome.org was introduced.

The number of available extensions grew to hundreds and instability some of them occasionally introduced seemed like a fair price for the unlimited tweakability. In the end when the Shell crashed it was just a blink. Xorg held up the session with opened clients, the Shell/Mutter was restarted and the show could go on.

In 2016 GNOME switches to Wayland by default. No Xorg and also nothing to hold up the session with opened clients when the Shell crashes. There is only Mutter as a Wayland compositor, but unfortunately it runs in the same process as GNOME Shell (a decision also made 10 years ago when it also looked like a good idea). If the Shell goes down, so does Mutter. Suddenly harmless blinks became desktop crashes with losing all unsaved data in opened applications.

I read user feedback and problems users are having with Fedora Workstation (and Linux desktop in general) a lot on the Internet. And desktop crashes caused by GS extensions are by far the most frequent problem I’ve seen recently. I read stories like “I upgraded my Fedora to 28 and suddenly my desktop crashes 5 times a day. I can’t take it any more and I’m out of ideas” on daily basis. If someone doesn’t step in and say: “Hey, do you have any GS extensions installed? If so, disable them and see if it keeps crashing. The extensions are not harmless, any error in them or incompatibility between them and the current version of GS can take the whole desktop down”, users usually leave with the experience of unstable Linux desktop. It hurts our reputation really badly.

Are there any ways to fix or at least improve the situation? Certainly:

  1. Extensions used to be disabled when the Shell crashed hard (couldn’t be restarted). Since on Wayland it’s the result of every crash, we should do that after every GS crash. And when the user goes back to GNOME Tweak Tool to enable the extensions again, she/he should be told that it was mostly likely one of the 3rd party extensions that made the desktop crash, and she/he should be careful when enabling them.
  2. Decoupling GNOME Shell and Mutter or/and other steps that would bring back the same behaviour like on Xorg: GS crash would not take everything down. This would require major changes in the architecture and a lot of work and GNOME Shell and Mutter developer community has already a lot on their plates.
  3. Discontinuing the unlimited extensions, introducing a limited API they can use instead of hot patching the GS code itself. This would be a very unpopular step because it’d mean that many of the existing extensions would be impossible to implement again. But it may become inevitable in the future.
Fedora, GNOME, Linux

Why I use Flatpak for 3rd party apps

flatpak-logo

There are more reasons why to run applications as flatpaks. Someone wants to have the latest versions as soon as possible. For me as a user of Fedora which provides up-to-date versions of apps this is not a big motivation. Someone wants to run apps more securely. Again I usually trust software provided by Fedora and Flatpak sandbox is still not as strictly enforced as it should ideally be.

But where I really prefer using Flatpak to RPM packages are 3rd party applications. I’m usually running development versions of Fedora. Pre-releases on my work machine and Rawhide on my home laptop. They have been pretty stable for me, including applications in Fedora repositories. Unfortunately it’s not the case for 3rd party applications. Their authors usually don’t follow distro development closely and although many of them bundle as much as possible to avoid problems with changing dependencies, things break.

I used to use the Spotify client as a package from Negativo17 repos. But when I upgraded to F27, something broke and it stopped working. I’m pretty sure it was fixed later on after people started reporting it, but I didn’t want to stop using Spotify for the time being and didn’t have time to debug and report the issue. So I switched to Spotify flatpak and it has worked for me ever since.

The problem I had with very early stages of pre-released Fedora and Rawhide is that dependecies of GStreamer plugins in RPMFusion were usually broken. So I ended up without system multimedia codecs. It was often the case for VLC from the same repository, too. Then I switched to VLC and GNOME MPV flatpaks. Problem solved.

The last example is Telegram. Until recently I was using the official version. It’s not even provided as an RPM package. You have to download an archive, unpack its content to your home, run the binary which creates a desktop file… not very elegant in 2018, but once you do it, it just works. Well… until it doesn’t. I upgraded to F28 and Telegram suddenly took a lot of time to start up. It hung on some font config error until it timeouted and finally started. It easily took 1 minute. So I switched to Telegram flatpak as well. Works like a charm.

So what I really appreciate about Flatpak is that the apps don’t rely on the underlying system, so if the system changes e.g. due to upgrade to a newer major version apps don’t break. As I said it’s not such a major issue for distro-provided apps, but it’s certainly an issue for 3rd apps and Flatpak solved it for me.

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.

flathub

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 5.4.3.2, Dec 1 5.4.4.2, 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