How to connect a snap interface

Snap interfaces grant or deny a confined snap's access to host resources such as cameras, removable media, audio recording, hardware devices, and shared services. When an application cannot see a resource that the host can see, the interface connection is often the first place to check.

Interfaces connect a snap plug to a slot. Many safe interfaces connect automatically during installation, while others require a manual snap connect command because they expose hardware, private files, or another sensitive host capability.

A completed connection should appear in snap connections <snap> with the expected plug and slot. The final proof is the application using the resource, because a visible connection only proves the access rule was applied.

1. List the snap's current interface connections.

   $ snap connections vlc
   Interface       Plug                Slot              Notes
   audio-playback  vlc:audio-playback  :audio-playback   -
   camera          vlc:camera          -                 -
   home            vlc:home            :home             -

   A dash in the Slot column means the plug is not connected.

2. Inspect the interface before granting access.

   $ snap interface camera
   name:    camera
   summary: allows access to all cameras
   plugs:
     - vlc
   slots:
     - snapd

3. Connect the snap plug to the system slot.

   $ sudo snap connect vlc:camera :camera

   Connect only the interface needed for the task. Interfaces such as camera, audio-record, and removable-media expose real host resources.

4. Confirm that the plug is connected.

   $ snap connections vlc
   Interface       Plug                Slot              Notes
   audio-playback  vlc:audio-playback  :audio-playback   -
   camera          vlc:camera          :camera           manual
   home            vlc:home            :home             -

5. Test the application access that previously failed.

   $ vlc v4l2:///dev/video0
   VLC media player opens the camera input

   Use the application action that triggered the missing-access symptom, such as opening a camera, recording audio, or browsing removable media.

6. Disconnect the interface when temporary access is no longer needed.

   $ sudo snap disconnect vlc:camera :camera