Cannot access file /usr/share/alsa/alsa.conf

snapd
1

Hello !

I’m trying to build my first snap, and of course, it builds ok but it’s not running :slight_smile:

I’m trying to enumerate the machine’s sound devices, using alsa (libasound2).

The enumeration goes well, but then I try to open the device to get its details, and that when the app fails :slight_smile:

ALSA lib conf.c:3750:(snd_config_update_r) Cannot access file /usr/share/alsa/alsa.conf
ALSA lib control.c:954:(snd_ctl_open_noupdate) Invalid CTL hw:0
Can't open card 0: No such file or directory

The error occurs when calling snd_ctl_open() (at line 72 in src/ui/ui.c if you clone the repository).

I’m new to snaps, so I might have made something wrong. I’ve looked on this forum and stackoverflow and some random, probably outdated, blogposts, but I couldn’t make it work.

Here’s my snapcraft.yaml file :

name: picaster
version: "0.3-git"
summary: PiCaster
description: |
  PiCaster is a podcast recording and streaming application,
  easy to use for beginners, but with enough functionality
  to suit the needs of intermediate or experienced podcasters.

confinement: devmode

apps:
  picaster:
    command: desktop-launch picaster
    plugs: [alsa,pulseaudio,home,gsettings,x11,desktop,network,network-bind,removable-media]

grade: devel

parts:
  picaster:
    after: [desktop-gtk3]
    plugin: autotools
    source-type: git
    source: https://github.com/picaster/picaster.git
    build-packages:
      - build-essential
      - libgtk-3-dev
      - libasound2-dev
    stage-packages:
      - libasound2

Should you want to compile the repo “by hand” :

sudo apt install build-essential libgtk-3-dev libasound2-dev
git clone https://github.com/picaster/picaster.git
cd picaster
autoreconf -fiv
./configure datadir=$(pwd)
make

Then run src/picaster

Thanks for your help !

2

alsa is a bit weird in that it hardcodes paths in its configuration files so you need to jump through a number of hoops to get it to work to snap things that use it when starting from scratch.

IIRC, @Wimpress and/or @lucyllewy made this easier for people. Perhaps they can comment?

3

I’ve build some “remote parts” which are attempting to fix things, but there’s still an issue with the paths they generate because of https://bugs.launchpad.net/snapcraft/+bug/1766878

4

Thanks, I’ve subscribed to the bug’s notifications and I shall report back when it’s fixed.

5

IF you do not use the $SNAPCRAFT_PROJECT_NAME variable anywhere in your snapcraft.yaml (which you do not seem to do), you should be safe from this bug and be able to just use the remote part.