pygame.error: > No available audio device when running pygame inside systemd with pulseaudio

Question

I want to run pygame mixer inside systemd, i used this code as an example:

from pygame import mixer
import signal,sys,time
def signal_handler(signal,frame):
    global inter
    inter=True
    sys.exit(0)

signal.signal(signal.SIGINT, signal_handler)


def play_audio_file(fname):
    if mixer.get_init() != None:
        mixer.quit()
    mixer.init()
    mixer.Sound(fname).play()



while True:
    play_audio_file('/home/mohammad/tmp/ding.wav')
    time.sleep(0.5)

and the following systemd service file:

[Unit]
Description=pygame mixer test
Wants=network-online.target
After=network-online.target

[Service]
Environment=VIRTUAL_ENV=/home/mohammad/env
Environment=PATH=/home/mohammad/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
ExecStart=/usr/bin/python /home/mohammad/tmp/service.py

WorkingDirectory=/home/mohammad/
StandardOutput=inherit
StandardError=inherit
Restart=always
User=mohammad    
[Install]
WantedBy=multi-user.target

When I start the service without other programs the script works as expected (the wav file play repeatedly) but when I start a program that output sound and then start the service I get this error:

Mar 02 01:12:04 mohammad-pc python[3415]: ALSA lib pcm_dmix.c:1099:(snd_pcm_dmix_open) unable to open slave Mar 02 01:12:04 mohammad-pc python[3415]: Traceback (most recent call last): Mar 02 01:12:04 mohammad-pc python[3415]: File "/home/mohammad/tmp/service.py", line 20, in Mar 02 01:12:04 mohammad-pc python[3415]:
play_audio_file('/home/mohammad/tmp/ding.wav') Mar 02 01:12:04 mohammad-pc python[3415]: File "/home/mohammad/tmp/service.py", line 14, in play_audio_file Mar 02 01:12:04 mohammad-pc python[3415]:
mixer.init() Mar 02 01:12:04 mohammad-pc python[3415]: pygame.error: No available audio device

This problem only appears on my manjaro linux machine running pulseaudio, but when I run the same code in my raspberrypi(raspbian strech) which runs alsa only without pulseaudio then the problem is resolved.

I was able to solve the problem (on my manjaro machine of course) by passing the DISPLAY and Home environment variable inside the service file like so:

[Unit]
Description=pygame mixer test
Wants=network-online.target
After=network-online.target

[Service]
Environment=VIRTUAL_ENV=/home/mohammad/env
Environment=PATH=/home/mohammad/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
ExecStart=/usr/bin/python /home/mohammad/tmp/service.py
Environment=DISPLAY=:0
Environment=HOME=/home/mohammad
WorkingDirectory=/home/mohammad/
StandardOutput=inherit
StandardError=inherit
Restart=always
User=mohammad

[Install]
WantedBy=multi-user.target

But I want to understand why would pygame needs these variables and can this be avoided ?

UPDATE 1:

when I included pygame in my main project(other than the example code above) I also needed to include Environment=XDG_RUNTIME_DIR=/run/user/1000 for it to work properly

pygame.error: > No available audio device when running pygame inside systemd with pulseaudio

0 Answers0