Package managers: Flatpak - Linux Desktop Applications

 

Flatpak is quickly becoming the best way to get Linux desktop applications up and running on a Linux PC. Flatpak applications operate in a sandbox with their own images and environments that download and mirror the existing system in an isolated environment. Once installed, the applications themselves offer a responsive, essentially native experience.

Case in point, all my work requires me to use Google Chrome, Slack, and occasionally Signal on my Linux desktop. All of these can run as Flatpak applications, and in some cases perform even better or more reliably as a Flatpak install vs a native desktop client. 

When first installing Flatpaks, there is some overhead. When installing, if there is a specific environment - say a graphics driver / library - required, than the application will list it as an additional download. This can eat away at disk space versus a native application, but often it is trivial in the long run given the size of modern disk drives, and the fact that most of these environments will be re-used by other applications overtime. 

While not terribly in depth, the above video seeks to demonstrate quickly the different ways for getting started with Flatpaks, how to use the command line interface, and hopefully how to better use Flatpaks to get up an running with Linux on the desktop (i.e. a computer with point and click, not just a terminal).

More information:

https://flatpak.org/

https://docs.flatpak.org/en/latest/basic-concepts.html

Good info from System76

More specific permission settings that may be needed with certain Flatpaks

Fixing filesystem permissions in Flatpak

 

I had a problem with my Flatpak installation of Slack - I couldn't save files. 

I don't recall this being an issue before, but in my new computer with Ubuntu Mate 21.10, it was. 

Turns out the solution is fairly straightforward. 

Flatpak has the option to specify a file path which can then be written to. If this file path is then the default download folder everything is copacetic.

Steps:

Close Slack and make sure it is not running in the background. 

Run flatpak ps to ensure com.slack.Slack is not listed.

Create a directory for storing the download files. This can be in your file manager (Nautilus, Caja, Dolphin, Thunar, etc.), or with the mkdir command.

Once created you can run the following:

flatpak override com.slack.Slack --filesystem=<your full directory path>

*This command needs to be run as root in my testing (use sudo). 

Then start the Slack application again and go to Preferences -> Advanced -> Download location. Set it the same as the directory path just mapped. 

That's it. Files should now be able to be saved to that specific directory. 

Hope it helps anyone who needs to do something similar in Slack or another Flatpak application.