sox not configured for pulseaudio when packaged in a snap

[Nathan Haines]

I am trying to snap package a whitenoise generator. It consists of a script that calls sox with a command line. Installing the package "sox" is its only dependency.

When running the installed snap, the following error occurs:

nhaines@savanna:~$ spacedrive
play FAIL sox: Sorry, there is no default audio device configured

At first, the only stage package was sox, attempts with and without libsox-fmt-pulse and pulseaudio were also tried with no success. The resultant

At last attempt, the following files are used:

root@spacedrive-snap:~/spacedrive-test# cat snap/usr/bin/spacedrive
#!/bin/sh
echo -n "\033]0;spacedrive\007"
AUDIODRIVER=Pulseaudio; play -n -c1 synth whitenoise lowpass -1 120 lowpass -1 120 lowpass -1 120 gain +14

root@spacedrive-snap:~/spacedrive-test# cat snapcraft.yaml
name: spacedrive
version: 0.1
summary: Generate a space travel engine for background noise
description: |
   Spacedrive simulates the soothing, rhythmic sound of a spaceship's
   space-time warp drive engines to help you concentrate or relax.
confinement: strict

apps:
  spacedrive:
    command: usr/bin/spacedrive
    plugs: [pulseaudio]

parts:
  spacedrive:
    plugin: copy
    files:
      spacedrive: usr/bin/spacedrive

  sox:
    plugin: nil
    stage-packages:
      - sox
      - libsox-fmt-pulse
      - pulseaudio

[John Lenton (chipaca)]

Sorry it's taken so long to get to this.
I'm not at all clear as to why this is a bug in snappy.
Please reopen with more details if it's still an issue.