Category Archives: Discover

Snap in Discover and the GNU/Linux Desktop

Last week I attended a sprint with the Snap team and some other members of the community. One of the things we looked into was the Software Center story at depth so I thought it’s a good moment to give you an update.

Discover’s Snap Backend

Long due, some of you have already been using the testing version of it. During this sprint it was refactored to use the snapd-glib library that should simplify a bit the maintainership of this piece of software.
I’m aiming to having a stable snap back-end for Plasma 5.11.


One of the reasons holding us back was the lack of AppStream support both in few spaces: getting proper information from the application, leveraging the appstream identifiers. This will allow snap software centers to have rich information ready for users to better choose their software.

My understanding is that the development of these features is well under way and should be available to us soon.

Desktop integration

One of the really cool things about Snap is how well it integrates with cloud/IoT stuff. While this makes it really powerful, us desktop users and developers have seen some things that will need tackling eventually. Things like styling, fonts, icons, etc. need to be properly represented in Snap and it’s good to see this coming together nicely.
These were all subjects that were discussed during the meeting, so do get your hopes high!

Discover more in 2017

With 2017 starting, we’re getting ready for the next Plasma 5.9 release and with it a new Discover release.

This will be a special release for two main reasons: further add-ons integration and Kirigami.

New Stuff

One thing pending for a long time was to actually better integrate the different parts of the system that can be integrated. To do so, Discover now will automatically import all knsrc files present on the system and offer them as categories.
We’ll be able to go beyond Plasmoids and Comics (!) and make it possible to explore: Plasma Look and Feel themes, cursors, icon themes, window manager add-ons and different application-specific resources.

This won’t have a big impact on Discover’s performance because the backend code was refactored to be able to have several backends loaded even without knowing all of the resources available. Queries are now asynchronous and parallel.

Discover KNS Addons


Kirigami was adopted in the previous release already, and this release will use Kirigami 2, the port to which did not require much work.

The most significant improvement is the inclusion of keyboard navigation, which was requested by several people and is now finally available. Do you hate it when you’re required to use the mouse? Rejoice!

Extra: Snappy support

It’s 2017, not all of the applications are coming from your distribution anymore. To start getting things in place for different software distribution sources I started working on a Snap backend, which allows us to manage applications coming from this system.
Some work will still be required and it won’t be included by default, since it doesn’t yet support AppStream (although we discussed it and it seems it will happen soon), but if you’re curious feel free to take a look and give your feedback!

GNU/Linux bundled application ramblings

It’s impressive how in the last few months (and especially the last few weeks) the discussion around bundled applications for the GNU/Linux Desktop has sparked.

It’s especially interesting because:

  • The problem is not new.
  • The solutions that have attempted to tackle the problem in the past have been ignored (both by us developers and by distributions).


First, let me try to subjectively summarize the problem: Historically, the resources we get in GNU/Linux come from the distributions. Anything: executables, libraries, icons, wallpapers, etc. There’s been alternatives to all of those, but none has flourished as a globally adopted solution.

This guarantees that everyone using a distribution will have access to the resources the distribution can offer. The more powerful the distribution is, the more we get. There’s limitations nevertheless, so some restrictions have to get in place. The ensemble of limitations and technologies adopted will effectively define the user’s experience.

This works. It has worked for years and, given the technology is in place, it could easily keep working. Like in most engineering solutions there’s drawbacks and properly addressing them can bear some goodness. It seems like now it’s the moment to review this situation. Let’s enumerate some of the problems we have nowadays:

  • We have users using really old versions of our software with issues we’ve solved in versions they can’t use.
  • It’s really hard for GNU/Linux users to get users to test unstable versions of our software.
  • We have users who want to use fresh versions of some software but not in the whole system.

There’s been many solutions to fix those, some easily come to mind: ArchLinux’s AUR (with yaourt), Ubuntu’s PPAs, big-tar application packages, OpenSuse’s OBS, and possibly others.

Far from showing the maturity of the Linux desktop, what this depicts is the deep fragmentation we’re into: we have come up with different solutions that break the established distribution paradigm by lowering the restrictions and considering the resources offered as unsupported (often tainting the whole system).

What has appeared recently is sandboxing. It’s especially interesting because by letting the users execute any binaries we’re increasing the exposition of their systems. Hence, jumping from our distributions’ nest into the lions. As always, sandboxing creates new challenges: It requires changes in applications (or frameworks) to adapt, often creating a user interaction fence (e.g. a popup asking if you let Kamoso access the webcam). For what it’s worth, that’s not new: Android does it, OS X does it, Windows does it (from the Store), Chrome OS does it, etc.

Now where are we?

We need to decide about GNU/Linux’s future. Or at least, we need to understand what Plasma users will have available. So far, most of the noise comes from the big players in the business trying to differentiate their products, meaning incompatible versions.

Without an agreed unified solution, we’ll have to assume we’ll end up having installed snappies, flatpaks, AppImages as well as applications from the distribution. Then it’s just a matter of:

  • Presenting it properly so that the user knows the risks taken by executing an application (!)
  • Make sure we don’t lose many features by sandboxing.

Still, one of the good things of this new approach is that it shouldn’t have to be necessary to have several people dedicated to build every single application and component. If the solution is to add 3 more solutions that will need dedicated people, we’re not really moving forward.


As soon as we’ve decided how we want to work, then the interesting stuff needs to appear. If this is properly engineered, it can bring really interesting possibilities that now we hardly ever find:

  • Newer versions of applications on administered systems (e.g. universities).
  • Enabling stable distributions on professional environments.
  • Beta channels.
  • Binary application 3rd party extensions.
  • Provision of debug symbols (some distros don’t offer them).

To finish the fantastic post, a note for the dreamers:
How easier would all that be in a microkernel architecture?

We need you!

Of course this will be a long journey and we need your collaboration. This year in Randa we started working on all these problems in several different angles. It’s important for the KDE Community to have your support, so we can keep providing quality software. Consider donating, doesn’t need to be a lot, everything counts.

Discover in Plasma 5.7

I haven’t talked about what’s going on in the Discover front for a while, here’s a small heads up on what you’ll get in the next Plasma 5.7 release.

Back Ends

  • PackageKit (and AppStream): This one has received most of the care. It has been rearranged to instant load. Also we made it possible to integrate this backend with KNS/OCS, to show when there’s add-ons ready for an application.
  • KNSBackend: It’s being polished and adapted for new use-cases. First it used to focus on Plasma-centered assets, but we’ve worked towards making it possible to become a viable solution for Application add-ons as well. Furthermore it has been trimmed down to also provide fast startup while keeping its features.
  • QApt: The traditional QApt backend used in Kubuntu is now considered deprecated in favor of PackageKit, which I understand should be available properly on every GNU/Linux distribution, including Kubuntu. We kept it around because there’s been longstanding issues with PackageKit on Ubuntu, but I’m confident these will be solved soon.

Front End

We used to have many of them, they have now been reduced to two: Discover and the Notifier Plasmoid. This allows us to focus one GUI. Of course, you can still use Muon, Apper and Synaptic together with it, for more precise package management.

Regarding Discover, the main focus this year has been: performance, stability and Add-ons.

  • Performance: Mostly back-end work, and it has also benefited from improvements in KF5 and upstream Qt. Updating the dependencies will improve your Discover experience as well as that of other similar applications. Better usage of some model classes was also a nice improvement in some places.
  • Stability: We worked on making sure that things not only are sturdy but that the development process doesn’t get in the way of stability. To that end, I set up a testing framework so that changes are automatically tested, additionally to the manual tests the developers will do at some point.
  • Add-ons: One of the important parts of Discover, is to make sure the user is aware of the nice resources he has available. KNewStuff resources (mostly coming from kde-look and kde-files so far) have been available for a while, albeit mostly for Plasma enhancements. In this next release we allow these to extend applications themselves as well.


Discover‘s future is Kirigami. We have already some work lined up (see the kirigami branch), we are pending some design work so that it shines, but the approach is already quite promising!

Also I’d like to start working on the Flatpak backend, if nobody beats me to it. 😀

Stay tuned!

A special sprint at CERN


I came to the sprint hoping I could iterate 2 issues I’ve had been trying to get sorted with Plasma for a while:

  1. Integration testing for plasmoids
  2. Discuss how to keep pushing Discover for the next releases both with Plasma and the VDG.


The new testing infrastructure is in place and I hope I’ll get to merge soon this week. Feel free to peek: patch1 and patch2.
This is very important because it will allow us to make the testing of plasmoids systematic, to some extent, making it easier to develop plasmoids and containments while maintaining and increasing the delivered quality.

Regarding Discover, there’s lots of ideas. Definitely far more than we can materialize. For now, we’ll be delivering a much more polished experience for 5.6 both on the strictly technical side (better appstream and PackageKit integration, better use of QtQuick in some areas) as well as on the looks side, mainly thanks to Andrew and Thomas who keep pushing me whenever something is not entirely perfect, which is awesome.

Visual Design Group (VDG)

The first special thing was that there was a VDG sprint in parallel. It wasn’t VDG people who joined us, but an actual sprint. This was especially good because it allowed for a fluid back-and-forth of ideas. It’s especially important both to have some designers full of dreams kicking our asses from time to time, as well as some kind of pragmatism back to them so the good ideas can end up being part of our workflows.

Plasma + VDG


Another special thing about the sprint was having the WikiToLearn team over. It was their first actual sprint as well as first time we all met together in a KDE event. I think it worked great, despite being different communities in nature, it’s interesting to see how synergies kept happening. I’m sure there’s good space for collaboration and I’m looking forward to keep working together.



Apparently they have a particle accelerator there. What?!

AppStream offers a Cross-Distribution identifier for applications

One of the problems we’ve historically had in the GNU/Linux world (and especially in KDE, since we’re cross-distribution) is that we’ve always had a hard time at explaining how to install our applications. Basically because it’s different on each distribution.

My first approach to this problem was creating Muon Discover but that’s clearly not enough because, in the end, we seldom look for new applications. Often they will be recommended on a blog post or forum and we’ll want to install it. But then, while recommending it, it will either be a vague “you should try KMail” or a “you should ‘apt-get install kmail’ or whatever applies to your distribution.

What I’m proposing today is to embrace AppStream at the level of URL handlers (for web browser integration). AppStream shows GNU/Linux distributions maturity by offering a solution by letting the upstream projects set the identifier in their appdata.xml file (among other things) and then let distributions name the package however they want, rather keeping to push different naming schemes down each other throats.

AppStream has been supported in Discover for over a year now (only for PackageKit so far) and, since introducing this feature is straightforward, I implemented it in master.
If somebody wants to give it a go, test master and click here: KMail

I think this will be beneficial not only for KDE but any project packaged on GNU/Linux distributions that have a presence on the web and need to find their way in users’ installations. This will of course be limited to getting the URL scheme adopted by our peers.

/me winks at Gnome Software and Ubuntu Software Center.

Porting Muon Discover to KF5

Muon has been a project that I’ve been very eager to port and iterate for a longtime. I’m happy with the 2.0 series, lots of changes were made and it has served us well. More importantly though, we have a solid technology to keep pushing our work on.


Now the first change has been the port to Qt5 and KF5 and adoption of QtQuick 2. This has been one of the few projects that have suffered from it, especially because we did a couple of hacks so that Muon Discover would integrate with the rest of applications’ look and feel. In any case, it’s sorted out now, we adopted the new QtQuick Controls and it works quite good, only problem being the usage of QQuickWidget, but that will be solved eventually, when we have everything we need in place to take the next step towards better integration between KXmlGui and QtQuick.

What to expect?

The most important news is that it will be as good and fresh as it used to be, integrated with the newer look and feel themes, capable of offering different sorts of data, such as applications, wallpapers and plasmoids.

Furthermore, some new features will be introduced with the forthcoming Muon 3.0 that will change how we integrate Muon on our systems. First of all, Appstream is being adopted for good. Now it will be possible to get a useful PackageKit backend, which has been adopted recently.

  • Additionally, for the ArchLinux fans, I did some fixing on the PackageKit libalpm backend so now it can be used again. 😀 Still, work on the Appstream set up is needed and help is very welcome.
  • Since I wanted to use a good PackageKit reference implementation, I looked into Fedora. I’ve been trying to get it working, but haven’t succeeded that much yet. I expected Appstream to be a first class citizen there, and things keep falling apart. We’ll have to work more in this area.
  • Kubuntu will remain using QApt for now. It seems to be working properly and there’s no intentions to change. Debian has also been ported to use use the same backend, we are pending though on some decisions to be taken with regards of metadata sources, that is, Appstream again.

**shrug** Looks like we’ll have to give a good push to Appstream!


I would like to see different Plasma-oriented distributions embracing Muon as a resource management front-end. So far, resource management hasn’t been part of our user experience, with the exception of KNewStuff.

Additionally, there’s a forum thread where a new graphical design is being worked on so it doesn’t look all that clunky (especially managing to make QtQuick Controls applications look good).

All this is already available on our Git repositories. A final version will be released early 2015 together with Plasma 5.2, although I’d like to roll a stable version first, so distributions can start adopting it.