Bsrgvty

I have Ubuntu 18.04 LTS installed.

I inserted USB-flash to my laptop. It was automounted to /media/username/DISKLABEL and opened in Nautilus. I can read and write objects to it.

How can I access it from the application, which is installed as Snap?

I tried snaps of the following applications such as gedit, arduino-mhall119, organize-my-files. All them show me errors if I navigate to /media folder:

Output of active Snap interfaces is below:

$ snap interfaces | grep -v ".*-$"
Slot Plug
:browser-support organize-my-files
:core-support core:core-support-plug
:cups-control gedit
:desktop gedit,organize-my-files
:desktop-legacy gedit,organize-my-files
:gsettings gedit,organize-my-files
:home arduino-mhall119,gedit,organize-my-files
:network arduino-mhall119,gedit,organize-my-files,pulsemixer
:opengl organize-my-files
:pulseaudio organize-my-files,pulsemixer
:unity7 arduino-mhall119,gedit,organize-my-files
:wayland gedit
:x11 arduino-mhall119,organize-my-files,pulsemixer
gnome-3-26-1604:gnome-3-26-1604 gedit
gtk-common-themes:gtk3-themes gedit
gtk-common-themes:icon-themes gedit
gtk-common-themes:sound-themes gedit
- arduino-mhall119:serial-port
- gedit:avahi-observe
- gedit:mount-observe

Updates:

• connecting mount-observe to Gedit with snap connect gedit:mount-observe does not help.


• it seems that we need special Snap with support of removable-media interface.

So we need special prepared Snap with support of removable-media interface/plugin.

Below is a list of Snap with removable-media plug described in YAML-manifest :

• vlc - VLC
  


• firefox - Firefox
  


• gimp - GIMP
  


• mdl - Markdown lint tool
  


• offlineimap - OfflineIMAP
  


• magic-wormhole - Magic Worm Hole
  


• mattermost-desktop - Mattermost
  


• storjshare-gui - Storj
  


• opentoonz - OpenToonz
  


• opentoonz-morevna - OpenToonz - Morevna Edition
  


• obs-studio - OBS Studio
  


• steamforwindows - Steam for Windows under Wine
  

One can find other Snaps released by SnapCrafters with the following GitHub search link.

So if the application does not have auto-connect of removable-media we need to connect it manually with:

snap connect some-snap-name:removable-media

But not all applications have this plug/interface in YAML-manifest.

It is hard to find packages by supported plugs - so I created issue "Add ability for parametric Snap search with filters (plugs, such as removable-media and so on)" about snapcraft.io site.

The bug about snap command named "snap should provide functionality to find packages with needed plug or connector" was filed to launchpad as bug 1776938.

The interface which needs to be connected is removable-media.

Can access files from removable media in /media and /run/media. This can be used to give an app access to mounted USB sticks and external hard drives on a desktop.

The mount-observe interface only lets you view what is mounted, not access mounts:

Can query system mount information. This is restricted because it gives privileged read access to mount arguments and should only be used with trusted apps.

Neither of these two interfaces will auto-connect. From https://github.com/snapcore/snapd/wiki/Interfaces#removable-media

The Ubuntu Software program will now show a Permissions button on the page of each Snap program you have installed.

Click on Permissions, and a pop-up window gives you the option 'Read/write files on removable storage devices', with a button to the right that you click to turn this on.

You need to activate each program one by one this way, but there is nothing special to remember, other than that the button exists.