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Learnings from Building an AppImage
For some time I am offering an AppImage of Kraft to make installations for users as easy as possible. Unfortunately real linux packages are big effort for the variety of distributions, and having one way to rule them all seems very appealing.
My first AppImage versions were pretty faulty when looking into details. So I spent some time to improve it recently, with the great help of the friendly people from AppImage community.
Here is my little report about what I have learned. If there is something I can do better, please let me know (unless it is use $OTHERTOOL).
How to build an AppImage?
At first, it makes sense to build the AppImage automatically via Github Actions. GH Actions are powerful, and well integrated. I also looked into using the openSUSE Buildserver for that, which works, but Github Actions seemed easier.
I got convinced by @TheAssasin to use AppImageCraft to build the image. That simplifies the process significantly by hiding a lot of auto generating things under the hood. While that leads to very clean and short config files for the AppImage build, it is harder to deal with issues that might come up because things are covered.
If I would not have had help from the dev that I know personally, I probably would not have survived the process. Yet, AppImageCraft is an awesome utility, yet a bit better documentation would help a lot.
Python Components
Kraft has a few Python components that are called from Kraft to do specialized tasks that I did not want to reimplement in C++. For example, it uses the awesome tool weasyprint to generate PDF from html.
While the AppImage can call a weasyprint installation that is installed on the host system that is not a good solution as there is no way to control if the required tool is really installed. So bundled Python is needed with all the dependencies for the external deps.
To achieve that, there is a very useful linuxdeploy-plugin called conda that uses conda to install Python. It installs the required python libs via pip and make them available in the bundle. Very convenient.
Pathes
To be a good citizen in the AppImage world, the app needs to be careful with pathes. When running in the AppImage, it is advisable to not use for example classes like QStandardPath directly or even worse hardcode paths that do any loading of files the app needs. Since the file tree of the AppImage is just mounted somewhere in the host system, the app needs to consider that it is not installed in standard locations.
A good rule of thumb when locating a file to load is to always check relative to the binary path first (ie. ../share/kraft/data/), and if that does not exist, continue to check the standard paths of the host system.
In Kraft there were already utility methods to adjust paths which I could simply extend to work fine in the AppImage. Still, that is kind of fiddly as there are more places to consider than one expects.
Locate translation files
Also a result of the challenge described before is that the app did not find the translation files to load in the filesystem of the AppImage. The translation system (KLocalizedString in Kraft) does obviously not check the correct path inside the AppImage mount.
Setting an additional relative path to look up translations at runtime fixes that problem.
Icons
Another issue that required quite some work were icons. Kraft used icons from the system theme quite a lot. As long these are installed, because the user has the same fitting desktop environment, that is not an issue, and icons are found.
However, if the icon theme is not installed, the app just lacks icons which make it bad looking or even hard to use.
That can be solved by using own icons as fallback in the app. For simplicity and consistency I switched to a complete set of own icons that are now coming with Kraft. They are bundled to the app with the Qt resource system now.
Dependencies to the Outside
Last but not least: When preparing an app for AppImage it needs to be checked if the app has binary dependencies that can (or should) not be packaged into the AppImage for efficiency reasons. Kraft for example uses Akonadi for contacts. With that users can use KAddressbook to manage addresses and Kraft uses the address lists via Akonadi. Life is too short for reinvention of an Addressbook.
Of course one could think of bundling the entire Akonadi and KAddressbook into the AppImage of Kraft. But that seems overkill, as that would mean bundling a lot of stuff, and would bring KDE users two instances of KAddressbook (the one from their desktop installation and the one from the AppImage). Seems not a good idea.
So this seems to be the only downside of the new Kraft AppImage now: It can not use the Akonadi based address management. To fix that, there needs to be a non binary dependant way. There could for example be a way to sync contacts to a local file system and let Kraft pick them up from there. That way, users could use the address management they want (also for example google) and Kraft could still pick addresses from there. That needs more thoughts.
The good news on this that Kraft is still fully functional as the Akonadi integration is great, but optional.
Summary
An AppImage seems to be a great way of distributing desktop applications, because there is only one build to run on all distributions. Well, fingers crossed…
However, building an AppImage that really works flawlessly is not a simple task, as this blog hopefully illustrates a bit.
One thing would have helped me: A simple option to understand when the app loads things from the host system, rather than from within the AppImage, for example as commnd line switch when running the AppImage. That would have eased the path adjustment development described above.
What is next in that area: User friendly updating of the AppImage and a solution to the address management problem.
All changes were merged in Kraft master today, the resulting AppImages can be found here.
PDF Quirk Version Update
The good thing about this quiet holidays is that there is time to work on projects. I had a few nice changes of PDF Quirk laying around, and now finalized them to a new version. Please welcome PDF Quirk version 0.95!
What is PDF Quirk?
PDF Quirk is a little desktop utility to create PDF files from images, targeted to non nerdy desktop users.
Sending PDFs is (still) often a requirement in offices where people are asked to transfer PDF files via email, or better by pushing them through their private ownCloud.
The source images can either be loaded from file, or directly scanned with an hardware scanner. For that, PDF Quirk utilizes the tool scanimage from the SANE Projekt, to avoid reinventing the wheel. Configured once, that works like a charm.
Having scanned or picked the source images, they can be deskewed, turned and rearranged, and finally converted to a good quality PDF file with reasonable file size.
New Version 0.95
The new version brings a few features and some fixes:
- Images can deskewed now
- Basic PDF options like margin, paper size and orientation can be set
- The UI got a little cleanup
- Translations were added, first new language is German
- Dependencies were reduced, new Qt based PDF generator was implemented
- Builds with Qt5 and Qt6
Interested?
Check out PDF Quirks Website for more information.
PDF Quirk is free software. Please contribute through the Github repository.
ownClouds Virtual Files on the Linux Desktop
it could already be read somewhere that 2021 will be the year of Linux on the desktop 😀
Fine with me. Just to support that, I did a little hackery over XMas to improve the support for ownClouds virtual file system on the Linux Desktop.
What are Virtual Files?
In professional usecases, users often have a huge amount of data stored in ownCloud. Syncing these completely to the desktop computer or laptop would be too much and costly in bandwidth and harddisk space. That is why most mature file sync solutions came up with the concept of virtual files. That means that users have the full structure with directories and files mirrored to their local machines, but have placeholder of the real files in the local file manager.
The files, however, are not on the disk. They get downloaded on demand.
That way, users see the full set of data virtually, but save time and space of files they never will need on the local system.
The ownCloud Experience
ownCloud has innovated on that topic a while ago, and meanwhile support virtual files mainly on Windows, because there is an elaborated system API to work with placeholder files. As we do not have this kind of API on Linux desktops yet, ownCloud desktop developers implemented the following solution for Linux: The virtual files are 1 byte sized files with the name of the original file, plus a suffix “.owncloud” to indicate that they are virtual.
That works, yet has one downside: Most file managers do not display these placeholder files nicely, because they loose the MIME type information. Also, downloading and also freeing up the space of downloaded files is not integrated. To summarize, there is a building block missing to make that useful on Linux.
Elokab-files-manager with ownCloud
I was wondering if it wasn’t possible to change an existing file manager to support the idea of virtual files. To start trying I found the Elokab-files-manager which is a very compact, yet feature rich file manager built on Qt. It is built with very few other dependencies. Perfect to start playing around with.
In my Github fork you can see the patches I came up with to make Elokab-fm understand ownCloud virtual files.
New Functionality
The screenshot shows the changes in the icon view of Elokab-fm.
To make that possible, Elokab-fm now pulls some information from the ownCloud Sync Client config file and connects to the sync client via local socket to share some information. That means, that the sync client needs to run to make that work.
Directories that are synced with ownCloud now show an cloud overlay in the center (1).
The placeholder files (2) which are not present on the local hard drive indicate that by showing a little cloud icon bottom right. However, other than before, they are displayed with their correct name and mime-type, which makes this already much more useful.
Files, which are on the local disk as the image (3) show their thumbnail as usual.
In the side panel (4) there are a few details added: The blue box on the bottom indicates that the file manager is connected to the sync client. For the selected virtual file (2), it shows an button that downloads the file if clicked which would turn it into a non virtual, local file. There is also an entry in the context menu to achieve that.
Status
This is just a proof of concept and a little XMas fun project. There are bugs, and the implementation is not complete. And maybe Jürgen‘s idea of a FUSE layer to improve that is the better approach, but anyway. It just shows what is possible with virtual files also on Linux.
If you like that idea, please let us know or send a little PR if you like. We do not wanna fail providing our share on the year of the Linux Desktop, right? 😉
Building it from my Github branch should be fairly easy, as it only depends on Qt.
For openSUSE users, I will provide some test packages in my home project on Open Build Service.
Screensharing with MS Teams and KDE: Black Screen
In the day job we use Microsoft Teams. The good news is that it is running on the Linux Desktop, and specifically KDE. So far, so good, however, there was a problem with screensharing for me.
Whenever I tried to share my KDE screen, the screen became black, surrounded with a red rectangle as indicator for the shared area. The people who I shared with also just saw the black area, and also the mouse pointer as me.
The problem is described in a bugreport and there are two ways of solving it:
- Enable compositing: The red indicator rectangle requires that the window manager supports compositing. KWin can of course do that, and with that enabled, sharing works fine including the red rectangle.
- If compositing can or should not be used there is another workaround: As the bug report shows, renaming the file
/usr/share/teams/resources/app.asar.unpacked/node_modules/slimcore/bin/rect-overlayso that it is not used by teams fixes it as well. Obviously you wont have the red rectangle with this solution.
That said, it is of course preferable to use an open source alternative to Teams to help these evolve.
Kraft Version 0.95
The authors are happy to announce the new release 0.95 of Kraft. Kraft is free desktop software for managing office documents like quotes and invoices in the small enterprise for the Linux desktop.
With version 0.95 we do a big step forward in the way of generating documents: Until now (more than fifteen years!) Kraft uses the ReportLab python library to create high quality PDF documents.
While this has served us well, it has always been cumbersome to adopt the template for users needs. ReportLab uses a XML format as the template which has a bit of a steep learning curve and is not really easy with syntax.
This changes now: From version 0.95, Kraft supports the cool project WeasyPrint. The principle remains the same: The document is built of a text based template which defines the look of the output document. That gets filled with the document data and gets converted to a PDF document. But unlike ReportLab, Weasyprint is HTML based. Many people know a bit of HTML and thus will have an way easier time to adopt the template to personal needs.
Apart from the ease of use, it is much more simple to do modern report design with Weasyprint, as it supports the wide range of CSS styling.
That is a great improvement, as adopting Krafts output to personal needs is much more intuitive now. For now, Kraft supports both rendering engines, but ReportLab based reports are deprecated now and support will end in future releases of Kraft.
Along with integration of Weasyprint the text templating library Grantlee was added, as it is the standard in the KDE/Qt world, well maintained and widely available. The ctemplate library which was used for that so far will also be deprecated.
The other great improvement in this release is that Kraft now has a user manual embedded which will give new users a guiding help. It will open in the browser once the user clicks on the menu entry in the help menu, also without internet connection. It was started by a community member and it will grow and improve over time.
As usual this new version also ships an amount of bug fixes and small improvements which can be found in the Changelog.
We wish all users big fun with this remarkable new version of Kraft.
Welcome PDF Quirk
How often have you scanned a letter, a certificate or whatever and looked for the right way to call $UTILITY to convert it to a PDF that can be shared via internet?
For this very common use case I could not find a tool to make that really easy for the Linux desktop. Given my mission to help making the Linux desktop more common in the small business world (do you know Kraft?) I spent some time starting this little project.
Please welcome PDF Quirk, the desktop app to easily create PDFs out of images from storage or directly from the scanner!
It is just what this screenshot shows: A one page app to pick images from either the harddisk or from a scanner if configured, and save it right away to a multi page PDF file. The only option is to have either monochrome or color scan. No further scan chi-chi, just nice PDFs within seconds.
Of course I did not want to spend too much time and reinvent the wheel. PDF Quirk uses ImageMagicks convert utility and the command line scan client scanimage of the SANE Project in the background. Both are welknown standard commands on Linux, and serve well for this purpose.
Maybe you find PDF Quirk useful and wanna try it. You find it on Github, or packages on the openSUSE Buildservice.
Contributions and comments are very welcome. It is a fun little project!
Eighty Percent ownCloud
Recently the German computer magazin C’t posted an article about file sync solutions (“Unter eigener Regie”, C’t 23, 2018) with native sync clients. The article was pretty positive about the FOSS solution of… Nextcloud! I was wondering why they had not choosen ownCloud’s client as my feeling is that ownCloud is way more busy and innovative developing the desktop client for file synchronization together with community.
Code lines changed as of Nov. 10, 2018
That motivated me to do some investigation what the Nextcloud client actually consists of (at due date Nov. 10, 2018). I was looking into the NC desktop client git repoository grouped the numbers of commits of people that can be associated clearly to either the ownCloud- or Nextcloud project, or to “other communities” or machine commits. Since the number of commits could be misleading (maybe some commits are huge?) I did the same exercise with numbers of changed lines of code.
When looking on the changed lines, the first top six contributors to the Nextcloud desktop client are only active in the ownCloud project. Number seven is an “other community” contributor whos project the client was based on in the beginning. Number eight to eleven go to Nextcloud, with a low percentage figure.
# of commits to the Nextcloud Desktop repository as of Nov. 10, 2018
As a result, far more than 80% of the changed lines of the Nextcloud client is actually work that ownClouders did (not considering the machine commits). In the past, and also today. The number would be even higher if it considered all the commits that go into the NC repo with an NC author, but are actually ownCloud patches where the original author got lost on the way by merging them through a NC branch. It looks like the Nextcloud developers were actually adding less commits to their client than all “other community” developers so far.
No wonder, it is a fork, you might think, and that is of course true. However, to my taste these numbers are not reflecting a “constructive” fork driving things forward when we talk about sync technology.
That is all fine, and I am proud that the work we do in ownCloud is actually stimulating two projects, with different focus areas nowadays. On the other hand, I would appreciate if the users of the technology would take a closer look to understand who really innovates, drives things forward and also fixes the nasty bugs in the stack. As a matter of fairness, that should be acknowledged. That is the motivation that keeps free software contributors busy and communities proud.
Change in Professional Life
This November was very exciting for me so far, as I was starting a new job at a company called Heidolph. I left SUSE after working there for another two years. My role there that was pretty far away from interesting technical work, which I missed more and more, so I decided to grab the opportunity to join in a new adventure.
Heidolph is a mature German engineering company building premium laboratory equipment. It is based in Schwabach, Germany. For me it is the first time that I am working in company that doesn’t do only software. At Heidolph, software is just one building block besides mechanical and electronic parts and tons of special know how. That is a very different situation and a lot to learn for me, but in a small, co-located team of great engineers, I am able to catch up fast in this interesting area.
We build software for the next generation Heidolph devices based on Linux and C++/Qt. Both technologies are in the center of my interest, over the years it has become more than clear for me that I want to continue with that and deepen my knowledge even more.
Since the meaning of open source has changed a lot since I started to contribute to free software and KDE in particular, it was a noticeable but not difficult step for me to take and move away from a self-proclaimed open source company towards a company that is using open source technologies as one part of their tooling and is
interested in learning about the processes we do in open source to build great products. An exciting move for me where I will learn a lot but also benefit from my experience. This of course that does not mean that I will stop to contribute to open source projects.
We are still building up the team and look for a Software Quality Engineer. If you are interested in working with us in an exciting environment, you might wanna get in touch.
Kraft Version 0.82
A new release of Kraft, the Qt- and KDE based software to help to organize business docs in small companies, has arrived.
A couple of days ago version 0.82 was released. It mainly is a bugfix release, but it also comes with a few new features. Users were asking for some new functions that they needed to switch to Kraft with their business communication, and I am always trying to make that a priority.
The most visible feature is a light rework of the calculation dialog that allows users to do price calculations for templates. It was cleared up, superflous elements were finally removed and the remaining ones now work as expected. The distinction between manual price and calculated price should be even more clear now. Time calculations can now not only done in the granularity of minutes, as this was to coarse for certain usecases. The unit for a time slice can now be either seconds, minutes or hours.
New calculation dialog in 0.82
Apart from that, for example sending documents per email was fixed, and in addition to doing it through thunderbird, Kraft can now also utilize the xdg-email tool to work with the desktop standard mail client, such as KMail.
Quite a few more bugfixes make this a nice release. Check the full Changelog! Update is recommended.
Thanks for your comments or suggestions about Kraft!
Kraft Version 0.80 Released
I am happy to announce the release of the stable Kraft version 0.80 (Changelog).
Kraft is desktop software to manage documents like quotes and invoices in the small business. It focuses on ease of use through an intuitive GUI, a well choosen feature set and ensures privacy by keeping data local.
After more than a dozen years of life time, Kraft is now reaching a new level: It is now completely ported to Qt5 / KDE Frameworks 5 and with that, it is compatible with all modern Linux distributions again.
KDE Frameworks 5 and Qt5 are the best base for modern desktop software and Kraft integrates seamlessly into all Linux desktops. Kraft makes use of the great KDE PIM infrastructure with KAddressbook and Akonadi.
In addition to the port that lasted unexpectedly over 12 months, Kraft v. 0.80 got a whole bunch of improvements, just to name some examples:
More Flexible Addressbook Integration
As Akonadi is optional now, Kraft can be built without it. Even if it was built with, but Akonadi for whatever reason is not working properly, Kraft still runs smoothly. In that case it only lacks the convenience of address book integration.
The Address book access was also nicely abstracted so that other Addressbook backends can be implemented more easily.
GUI Improvements
Even though the functionality and GUI of Kraft was not changed dramatically compared to the last stable KDE 4 version, there were a few interesting changes in the user interface.
- A new, bigger side bar simplifies navigation.
- In the timeline view, a click on years and month in the treeview show summaries of the selected time span, ie. the number of documents with financial summaries per month or year.
- A filter allows to limit the view on the current week or month.
Reduction of dependencies
Kraft makes broad use of the core Qt5 libraries. The required KDE dependencies were reduced to a bare minimum. Akonadi libraries, which enable KDE PIM integration are now optional. The former dependency on heavyweight web browser components were completely removed and replaced by the far more simple richtext component of Qt.
These changes make it not only easier and more transparent to build Kraft but allow make a port to other platforms like MacOSX more easy in the future.
Under the Hood
A countless number of bugfixes and small improvements went in. Also updates to the newer C++ concepts where applicable make the rather mature code base more modern and better maintainable.
The Reportlab based PDF document creation script was updated and merged with a later version for example.
Deployment
Installing Kraft is still a bit complicated for unexperienced users, and distributions sometimes haven’t made a good job in the past to provide the latest version of Kraft.
To make it easier to test, there is an AppImage of Kraft 0.80 available that should be runable on most modern distributions. Just download a single file that can be started right away after having added the executable permissions.
Linux packages are already built for openSUSE (various versions) or Gentoo.
Kraft’s website will contain a lot more information.
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