Failed to capture microphone input using pulseaudio as a systemd unit

Question

I created a small go program that uses these go bindings to record some commands from the default microphone and act accordingly. It works fine as a standalone binary(both as normal user and root user) but when I tried to convert it into a systemd unit the Capture function in the go bindings failed with error saying connection refused.

The program is failing to capture the microphone input when running as a systemd service. The following is the unit file which is pretty much copy-pasted from here.

[Unit]
Description=Commander service providing voice commands

[Service]
ExecStart=/path/to/binary/binary.sh

[Install]
WantedBy=multi-user.target

binary.sh is a simple shell script that for providing environment variables to the go binary. The script is below

#!/bin/bash
cd /path/to/binary
env LD_LIBRARY_PATH=/usr/local/lib ./binary > stdout 2> stderr

The LD_LIBRARY_PATH is needed for pocketsphinx shared libraries which is being used for recognizing commands from audio.

I think something is wrong with the unit file but I don't know what it is. The whole project can be found here.

Any insight would be helpful. Thanks.

PulseAudio generally runs in the context of the logged in user's session, and audio input/output is only possible for programs running inside that session. It should not be possible for a system service to obtain microphone audio from PulseAudio running in a user's session, as that would be a serious security breach. — Michael Hampton, Aug 15 '18 at 14:32
Hi, Michael. That makes a lot of sense. But it should be possible to run a service in user's session using `systemd`..? or do I have to use desktop environment's autostart mechanism to achieve what I want..? — Siddharth Shishulkar, Aug 15 '18 at 15:25
It sounds like this would make sense to run as a systemd user service (just like PulseAudio itself). — Lucas Werkmeister, Aug 16 '18 at 13:45

score 0 · Answer 1 · answered Aug 15 '18 at 11:54

0

pulseaudio is a daemon which probably has yet to get launched ... update your binary.sh with a

sleep 10
echo about to determine whether pulseaudio is up and running
pulseaudio --check
echo if pulseaudio is running above check silently returns

prior to launching your golang binary

answered Aug 15 '18 at 11:54

Scott Stensland

26,870
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Hi Scott, thanks for the input but `pulseaudio` is running. I'm testing the service side-by-side with the binary. The binary is running but the service is giving me problems. I'll add this check though once this problem is solved. – Siddharth Shishulkar Aug 15 '18 at 12:23

score 0 · Answer 2 · answered Mar 25 '22 at 16:48

0

It is required to set XDG_RUNTIME_DIR environmental variable to directory /run/user/<USER_ID>, e.g.

[Service]
Environment="XDG_RUNTIME_DIR=/run/user/1001"
ExecStart=/path/to/binary/binary.sh

answered Mar 25 '22 at 16:48

Vitalii Blagodir

939
9
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Failed to capture microphone input using pulseaudio as a systemd unit

2 Answers2