Running alsa inside daemon snap

Trying to run alsa inside daemon snap, I have add system-usernames: part to make the snap daemon not run root.

The snap works when it is not running as daemon

This is my yaml file:

name: app-name
base: core18
version: '0.2'  # Just for humans, typically '1.2+git' or '1.3.2'
summary: Single-line elevator pitch for your amazing snap # 79 char long summary
description: |
  This is my-snap's description. You have a paragraph or two to tell the
  most important story about your snap. Keep it under 100 words though,
  we live in tweetspace and your description wants to look good in the snap
  store.

  #grade: stable # must be 'stable' to release into candidate/stable channels
  #confinement: strict # use 'strict' once you have the right plugs and slots

grade: devel  # Must be 'stable' to release into candidate/stable channels
confinement: devmode
#architectures: [all]

parts:
  alsa-mixin:
    plugin: dump
    source: https://github.com/diddlesnaps/snapcraft-alsa.git
    source-subdir: snapcraft-assets
    build-packages:
      - libasound2-dev
    stage-packages:
      - libasound2
      - libasound2-plugins

  app-name:
    after: [alsa-mixin]
    plugin: dump
    source: .
    override-build: |

      cd scripts/bashScripts/
      ./compileAllCFiles.sh   # Have to be executed when working directory is this file location
      cd ../..

      snapcraftctl build

    build-packages:
      - wget
      - unzip
      - git
      - gcc
      - g++
      - make
      #      - python3-pip
      #      - libevent-dev
      #      - libperl-dev
      - libatlas-base-dev
      #      - libasound2-plugins
      - libasound-dev
    stage-packages:
      - libatlas-base-dev
      - libevent-dev

layout:
  /usr/lib/$SNAPCRAFT_ARCH_TRIPLET/alsa-lib:
    bind: $SNAP/usr/lib/$SNAPCRAFT_ARCH_TRIPLET/alsa-lib

system-usernames:
  snap_daemon: shared

apps:
  demo:
    command-chain: ["snap/command-chain/alsa-launch"]
    command: scripts/cScripts/demo $SNAP
    daemon: simple
    plugs: [network, network-bind, gpio, hardware-observe, audio-playback, audio-record, pulseaudio, alsa]

And this is the output that I get:

ubuntu@ubuntu:~$ sudo systemctl status -n 100 snap.app-name.demo.service 
‚óŹ snap.app-name.demo.service - Service for snap application app-name.demo
   Loaded: loaded (/etc/systemd/system/snap.app-name.demo.service; enabled; vendor preset: enabled)
   Active: failed (Result: exit-code) since Tue 2020-07-14 14:42:13 UTC; 13s ago
  Process: 6969 ExecStart=/usr/bin/snap run app-name.demo (code=exited, status=1/FAILURE)
 Main PID: 6969 (code=exited, status=1/FAILURE)

Jul 14 14:42:13 ubuntu systemd[1]: snap.app-name.demo.service: Service hold-off time over, scheduling restart.
Jul 14 14:42:13 ubuntu systemd[1]: snap.app-name.demo.service: Scheduled restart job, restart counter is at 5.
Jul 14 14:42:13 ubuntu systemd[1]: Stopped Service for snap application app-name.demo.
Jul 14 14:42:13 ubuntu systemd[1]: snap.app-name.demo.service: Start request repeated too quickly.
Jul 14 14:42:13 ubuntu systemd[1]: snap.app-name.demo.service: Failed with result 'exit-code'.
Jul 14 14:42:13 ubuntu systemd[1]: Failed to start Service for snap application app-name.demo.

This is a link to the project if it more convenient for you.
The .c file that I run is located in Alsa-snap-not-working/Again/scripts/cScripts/snowboy/examples/C/demo.c