Using pipe backend

[jagjordi]

Hello,
I am trying to use the pipe backend.
First I tried adding --backend pipe to the docker command but got the error Error parsing command line options: Option 'backend' given more than once.
Then I saw that in the entrypoint script the backend is set based on the OUTPUT env variable, which in the Dockerfile is empty.
I tried passing it to the docker command as follows.

docker run --rm \
    --name "spot" \
    --env "MOD_MDNS_NAME=Super Name For Your Spotify Connect Endpoint" \
    --env "OUTPUT=pipe" \
    --env "DEVICE=/tmp/spotify" \
    --volume /tmp \
    --group-add audio \
    --device /dev/snd \
    --net host \
    --cap-drop ALL \
    --read-only \
    docker.io/dubodubonduponey/spotify

But still I couldn't get it to work, when librespot boots it tryes to use ALSA card. See logs

ALSA lib confmisc.c:855:(parse_card) cannot find card '0'
ALSA lib conf.c:5180:(_snd_config_evaluate) function snd_func_card_inum returned error: No such file or directory
ALSA lib confmisc.c:422:(snd_func_concat) error evaluating strings
ALSA lib conf.c:5180:(_snd_config_evaluate) function snd_func_concat returned error: No such file or directory
ALSA lib confmisc.c:1334:(snd_func_refer) error evaluating name
ALSA lib conf.c:5180:(_snd_config_evaluate) function snd_func_refer returned error: No such file or directory
ALSA lib conf.c:5703:(snd_config_expand) Evaluate error: No such file or directory
ALSA lib pcm.c:2666:(snd_pcm_open_noupdate) Unknown PCM default
[2024-09-21T23:16:56Z ERROR librespot_playback::player] Audio Sink Error Connection Refused: <AlsaSink> Device default May be Invalid, Busy, or Already in Use, ALSA function 'snd_pcm_open' failed with error 'ENOENT: No such file or directory'

Am I doing something wrong?
Thank you!

[marco79cgn]

You have to use both --device /path/to/fifo and --backend pipe parameters, but not via --env. What I did is mounting the fifo (named spotpipe) from the docker host (/home/pi/music) into the container (/mnt/music) as volume.

Try this:

docker run -d --rm \
    --name "spot" \
    --env "NAME=Super Name For Your Spotify Connect Endpoint" \
    --volume /tmp \
    --volume /home/pi/music:/mnt/music \
    --group-add audio \
    --backend pipe \
    --device /mnt/music/spotpipe \
    --net host \
    --cap-drop ALL \
    --read-only \
    docker.io/dubodubonduponey/spotify

At the end I switched to this fork and got it running with this docker-compose.yml:

services:
  librespot:
    image: giof71/librespot:latest
    network_mode: host
    environment:
      - BACKEND=pipe
      - DEVICE=/mnt/music/spotpipe
      - BITRATE=320
      - INITIAL_VOLUME=100
      - DEVICE_NAME=SpotiPi
    volumes:
      - /home/pi/music:/mnt/music