Write plugin for Gnome Software

[probonopd]

Gnome Software is supposed to be modular and supposedly supports plugins for other software distribution mechanisms such as AppImage. Is there any documentation on how to write a plugin, preferably in Vala?

Need to investigate gs-plugin-limba.c, too.

[probonopd]

@hughsie of gnome-software states that there is no public plugin API (yet?) but AppImageUpdate integration would be "a great thing to add, and should be pretty easy" and suggests to have a look at the limba plugin and the xdg-app plugin in the wip/hughsie/xdg-app branch which both do a similar thing. He also kindly offers his help if required.

[probonopd]

There is now a snap plugin which possibly could give us some hints on how to write one for AppImage.

GNOME/gnome-software@82b15e9
"This allows you to browse snaps installed on your system and search for snaps from the snap store."

The snap plugin communicates with snapd which seems to do the "real work", such as "list snaps in the store that match the search term and that this system can handle".
So it looks like the snap plugin doesn't rely on AppStream information to make snaps available, but rather communicates with Canonical's Snapcraft store directly.

https://github.com/snapcore/snapd/blob/master/docs/rest.md

For AppImage, we want something more decentral, where the upstream application author is in control.

Also see #48

[hughsie]

There is now stable plugin api. See https://blogs.gnome.org/hughsie/2016/05/19/external-plugins-in-gnome-software/ for a good intro. R

[probonopd]

Thanks @hughsie. If you have a spare minute or two, I'd appreciate your thoughts on #48 (comment)

Note to self: https://people.freedesktop.org/~hughsient/gnome-software/plugins.html

[probonopd]

Trying to compile gs-plugin-example.c I get:

$ gcc -shared -o libgs_plugin_example.so gs-plugin-example.c -fPIC  `pkg-config --libs --cflags gnome-software`  -DI_KNOW_THE_GNOME_SOFTWARE_API_IS_SUBJECT_TO_CHANGE &&  sudo cp libgs_plugin_example.so `pkg-config gnome-software --variable=plugindir`
Package gnome-software was not found in the pkg-config search path.
Perhaps you should add the directory containing `gnome-software.pc'
to the PKG_CONFIG_PATH environment variable
No package 'gnome-software' found
gs-plugin-example.c:22:28: fatal error: gnome-software.h: No such file or directory
compilation terminated.

Ubuntu does not seem to have the required gnome-software.h file: Search

[hughsie]

Right, you need gnome-software from git; 3.20 is too old for the external plugin work. We'll only support out-of-tree plugins going forward in a stable release once 3.22 is released, sorry.

[probonopd]

Now that gnome-software 3.22.0 has landed in debian sid, I have been looking for gnome-software.h but it still seems to be missing; is there an ETA for it?

[probonopd]

Alternatively, how would I build gnome-software using JHBuild or manually from git?

[hughsie]

You can build gnome-software using jhbuild buildone gnome-software but in debian I assume you have to install a -dev subpackage to get the plugin headers.

[probonopd]

We'll only support out-of-tree plugins going forward in a stable release once 3.22 is released

@hughsie now that debian carries gnome-software 3.22.5-1 do you think it can be used to write plugins?

https://packages.debian.org/sid/gnome-software

[hughsie]

Yes, very much so.