How to play sound in a docker container

Question

I'm trying to dockerize a text to speech application for sharing the code with other developers, however the issue I am having right now is the docker container cannot find the sound card on my host machine.

When I try to play a wav file in my docker container

root@3e9ef1e869ea:/# aplay Alesis-Fusion-Acoustic-Bass-C2.wav
ALSA lib confmisc.c:768:(parse_card) cannot find card '0'
ALSA lib conf.c:4259:(_snd_config_evaluate) function snd_func_card_driver returned error: No such file or directory
ALSA lib confmisc.c:392:(snd_func_concat) error evaluating strings
ALSA lib conf.c:4259:(_snd_config_evaluate) function snd_func_concat returned error: No such file or directory
ALSA lib confmisc.c:1251:(snd_func_refer) error evaluating name
ALSA lib conf.c:4259:(_snd_config_evaluate) function snd_func_refer returned error: No such file or directory
ALSA lib conf.c:4738:(snd_config_expand) Evaluate error: No such file or directory
ALSA lib pcm.c:2239:(snd_pcm_open_noupdate) Unknown PCM default
aplay: main:722: audio open error: No such file or directory

I guess that the main problem is docker container is unable reach the sound card on my host.

So far I have

1. I installed alsa-utils and most of the alsa dependencies within my docker container.
2. Added --group-add audio while running the container by specifying docker run --group-add audio -t -i self/debian /bin/bash

I am not sure if this is even possible with docker(I'm not exactly sure of how hardware resources such as sound cards are shared with containers). I'm using a debian container on a Mac OS Yosemite host.

Answer 1

It is definitely possible, you need to mount /dev/snd, see how Jess Frazelle launches a Spotify container, from

https://blog.jessfraz.com/post/docker-containers-on-the-desktop/

you will notice

docker run -it \
    -v /tmp/.X11-unix:/tmp/.X11-unix \ # mount the X11 socket
    -e DISPLAY=unix$DISPLAY \ # pass the display
    --device /dev/snd \ # sound
    --name spotify \
    jess/spotify

or for Chrome, at the end

docker run -it \
    --net host \ # may as well YOLO
    --cpuset-cpus 0 \ # control the cpu
    --memory 512mb \ # max memory it can use
    -v /tmp/.X11-unix:/tmp/.X11-unix \ # mount the X11 socket
    -e DISPLAY=unix$DISPLAY \ # pass the display
    -v $HOME/Downloads:/root/Downloads \ # optional, but nice
    -v $HOME/.config/google-chrome/:/data \ # if you want to save state
    --device /dev/snd \ # so we have sound
    --name chrome \
    jess/chrome