Thumbnailer should be packaged as a snap

[James Henstridge]

We need to package Thumbnailer as a snap. Some requirements are:

  1. package should use strict confinement
  2. service should be usable from other strictly confined snaps
  3. thumbnailer-admin should be able to talk to thumbnailer-service
  4. ???

[James Henstridge (jamesh)]

thumbnailer-admin can't talk to thumbnailer-service. Ideally communication like this between apps from a single snap should be unrestricted:

https://bugs.launchpad.net/snappy/+bug/1659724

thumbnailer-service hits problems due to missing gdk-pixbuf loader cache. Seems to be an issue with desktop-launch script:

https://github.com/ubuntu/snapcraft-desktop-helpers/issues/42

[Daniel van Vugt (vanvugt)]

Thumbnailer sounds like something that should already be part of other snaps, not something that is potentially stand-alone...?

[James Henstridge (jamesh)]

Script to temporarily work around the gdk-pixbuf bug: http://paste.ubuntu.com/23891990/

[James Henstridge (jamesh)]

Fixed version of script: http://paste.ubuntu.com/23892004/

[Michi Henning (michihenning)]

> Thumbnailer sounds like something that should already be part of other snaps, not something that is potentially stand-alone...?

If each snap includes its own thumbnailer, each snap will redundantly store thumbnails (making the idea of a cache much less useful). Moreover, all the databases for the thumbnails will eat disk space like crazy.

[James Henstridge (jamesh)]

And yet another version that updates xdg-mime too: http://paste.ubuntu.com/23892565/

After generating the mime data and pixbuf loaders for both snaps, I was able to successfully perform an album art request from one snap to the other. So that's the minimum functionality working.

[James Henstridge (jamesh)]

Looks like snapcraft-desktop-helpers has been updated to mostly fix these problems. Still some rough edges, but the above script should become unnecessary soon.

[James Henstridge (jamesh)]

A pull request for a "thumbnailer" snappy interface:

https://github.com/snapcore/snapd/pull/2783