Distribute as Flatpak

[wvengen]

For ease of installation on multiple Linux distributions, it would be great to have a Flatpak, published on Flathub.

[wvengen]

I've started packaging in this repository. Currently it builds and runs, but needs additional permissions for good desktop integration, installing fluidsynth + soundfont, as well as icon, desktop file and such.

[wvengen]

Is there are preferred package identifier? I've used org.jjazzlab as prefix, since that is used in pom.xml as groupId.

[jjazzboss]

Thanks. "org.jjazzlab" is fine.

[wvengen]

Some questions that came up:

• Do you own the domain name jjazzlab.org? If not, then the id need to stick to jjazzlab.com, because the domain name needs to be owned for Flathub.
• Can we store the desktop file in this (or a related) repository? (flathub note) Perhaps also the AppData file (note this also contains a list of releases)?
• Do you have any release scripts? I would be happy to see if I can adapt them to automate updating the Flatpak on a new release (at least to some extent), somewhere down the line. That would also be a place to keep the logo, desktop file, etc (or perhaps ideally they go in this repository as well).
• Is the dark theme the default theme, or is it supposed to sync with desktop setting? Switching my desktop default didn't change anything for me. Important for screenshots to have the correct default.
• Could you put a screenshot (like this one) with dimensions 1000x700 pixels (not bigger, certainly not smaller than 624x351), e.g. on Github or the website? That would be referenced from the appdata file.

Other than the above, I think the Flatpak packaging is ready for submission.

[jjazzboss]

I'm not familiar with flatpak and don't have much free time recently, so thank you very much !

I do own jjazzlab.com and jjazzlab.org. Actually I am in the process of migrating everything to jjazzlab.org.

For the .desktop/comment on metainfo.xml/Summary, I would prefer "Generate backing tracks for any song"

I have a release bash script which uses nbpackage (Netbeans packager) to manage win/linux/MacOS stuff (JDK bundling + some minor tweaks), but I don't think it will help you much here. For 4.0.2 you would just need to add flag -J-Dmp.token=a67ed8aa58b306c1336dcf74fb99b2f69f1 in the sed command line 65 of jjazzlab.yml file. This is the public MixPanel API key. In the next release this won't be needed anymore.

Dark theme is by default, not synced to OS setting.

You can use https://github.com/jjazzboss/JJazzLab/blob/master/graphics/JJazzLab-1000x700.png

[wvengen]

Thanks for your reply!

I've applied your suggestions and submitted it to Flathub, and got a response that the desktop and metainfo file are expected upstream. Could you put them in the JJazzLab project, e.g. in misc? That also means you would need to add new releases to the metainfo file.

[wvengen]

One other thing that came up: regarding jjazzlab.org, could you add a placeholder text or redirect to jjazzlab.com? The reviewer doesn't approve of its current state and using it for the application id.

That's a bit problematic, since there's no way to verify ownership. If for some reason the transfer did not happen, the application ends up with the wrong id preventing future verification etc.

[jjazzboss]

Migration to jjazzlab.org should be complete next week I think, let's wait a little bit. I'll add the 2 files in my repo.

That also means you would need to add new releases to the metainfo file.

What do you mean ?

[wvengen]

Migration to jjazzlab.org should be complete next week I think, let's wait a little bit.

Super, that sounds great :+1:. If I could be of help, let me know.

I'll add the 2 files in my repo.

Thanks, I'll update the Flatpak manifest. From the next version on, it can be obtained from the source tarball directly.

That also means you would need to add new releases to the metainfo file.

The metainfo file has a list of releases: version, date, and optional info like a changelog. See Flathub's description of releases and Freedesktop's appstream on releases. Note that AppStream is used for various packaging methods, incl. Flatpak, Snap and AppImage.

Looking at existing apps on Flathub, this can also be auto-generated from git tags, e.g. as in this script (though that misses a changelog, I see this for multiple existing apps om Flathub).

[jjazzboss]

I just finished the migration, jjazzlab.com is gone, long live to jjazzlab.org ! :-)
I added the 2 files on master branch in misc/flatpak.

[wvengen]

Thank you, great to see! The desktop and metainfo files are not really Flatpak-specific, they should ideally also be present in other Linux packages. Typically, the desktop file can be installed in /usr/share/applications and the metainfo file in /usr/share/metainfo (Debian wiki, Fedora packaging guidelines). Maybe it's better to put them in misc/ (or misc/desktop/ or even misc/linux) instead of misc/flatpak?

[wvengen]

Note that the desktop file is used to show a launcher in the desktop launcher (think: start menu), and the metainfo file to show the application in something like an appstore (like Gnome Software; useful to read more about installed applications, and if someone includes your packaged program in a repository, then it will be findable in appstore-like programs).

[jjazzboss]

ah ok, moved to misc/

[jjazzboss]

Thanks for the submission, this is cool ! I'll test it tonight.

[jjazzboss]

One question: when I was developing JJazzLab 4, I tested it on a few Linux distros, fluidsynth sometimes made some crackling noise. I googled the issue and found that I had to update some Linux audio settings as explained here: https://jackaudio.org/faq/linux_rt_config.html. Indeed it solved the issue. Do you know if the flatpak could manage this ?

[jjazzboss]

By the ways if you use JJazzLab often, send me your email, I'll send you a donation code to avoid the nagging screen.

[wvengen]

Regarding audio crackling: I haven't found a clear way to know what to set here. For me, running pipewire, exposing the pipewire socket was enough. But under heavy load, real-time priority would be nice. I don't see a common practice in existing audio-related Flatpaks, though --device=all is usually included for MIDI (but as Java MIDI only works with low-level hardware devices, it is not that straightforward to cooperate with in a production setup - perhaps snd-virmidi, my bluetooth-MIDI device couldn't be found at all when running without Flatpak, for example). It is a little overkill, so I have excluded it until it's clearer what is needed here. Examples:

• Surge XT
• VMPK (contains a SuSE specific entry)
• Zrythm (talks with realtime dbus, perhaps that could be useful, does fluidsynth work with that, and do have distributions enabled this generally?)
• Elektroid (misses pipewire entry, but maybe ok if it doesn't speak JACK)
• Audacity (--device=all for ALSA, would need to look into what Flatpak requires for audio to see if that makes sense; Audacity has other needs here).
• LMMS (also pulseaudio and pipewire, also SuSE-specific entry)
• QSynth is a fluidsynth front-end (also pulseaudio and pipewire, --device=all for MIDI, SuSE-specific entry)

My conclusions are:

• Audio output is fine (pulseaudio + pipewire)
• Add SuSE-specific config
• Realtime might benefit from the dbus access, but needs further investigation on how fluidsynth could use it. At first glance fluidsynth may support it.
• MIDI needs work (maybe even on the Java side)

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Something else: you may want to verify your developer identity for the app to show a verified badge.

p.s. During development, the screen was annoying enough for me to find a solution for it. I really hope some finances will come your way, so the screen can be less prominent. If I start using JJazzLab a lot, I would definitely consider donating. Thanks for the offer though, much appreciated!

[jjazzboss]

For audio crackling: ok let's see how it goes as it is. I just verified the app on flathub. Ok for the nag screen :-) Don't hesitate to ping me if you don't have the time to rebuild and patch.