Exec Node, connection refused in service mode, ok when lnode red launched from terminal

[plouc]

Hello,
I have a flow executing commands to pulseaudio on a raspberry pi.
The flow works great when i launch node-red from the terminal (trough ssh), but when node red run as a service it is doing this error:
"
Command failed: pactl list sink-inputs
Connection failure: Connection refused
pa_context_connect() failed: Connection refused
"

I found this topic which i think is related:

The exec node fails to execute a command that works in the terminal

Hello everyone and thank you for all your answers avaliable on this forum which allowed me to discover node-red and a little programming. I am a total newbie and my question may seem silly to you: What can prevent an exec node from executing a command that works in the terminal? Let me explain : I would like to "mute" and "unmute" the raspberry 3b sound output with an exec node (i use pulseaudio). I tried many command found on various sources but: no succes. For example, the following two co…

If i understood well this is "because pulseaudio requires an Xwindow environment to run"

So how should i change the nodered.service file to enable the Xwindow environnement in service mode?

Thanks a lot for your help, i'm pretty new to linux and any help will be much appreciated!

[Colin]

Having done some research (ie google) it appears that it may be that if you want to access pulseaudio from node-red running as a system service then you will have to run pulseaudio as a system service too. Apparently it runs by default as a User service rather than a System service. I am working at the edge of my knowledge here though, so I might be wrong. As to how to run pulseaudio as a system service rather than a user service I don't know.

[plouc]

hi Colin and thanks for your answer.

Indeed, after questionning chatGPT for some time, it finally helped me to find a solution which is working!

If i understood well, it is indeed needed to start pulseaudio as a service.

So there is it's solution:

Modifying the file node-red.service with this content will make sure that pulseaudio runs as a service before starting node-red:

[Unit]
Description=Node-RED graphical event wiring tool
Wants=network.target
# here
After=pulseaudio.service
Documentation=http://nodered.org/docs/hardware/raspberrypi.html

[Service]
Type=simple
User=pi
Group=pi
WorkingDirectory=/home/pi

Environment="NODE_OPTIONS=--max_old_space_size=2048"
EnvironmentFile=-/home/pi/.node-red/EnvironmentFile

# and here
ExecStartPre=/usr/bin/pulseaudio --start
ExecStart=/usr/bin/env node-red-pi $NODE_OPTIONS $NODE_RED_OPTIONS
KillSignal=SIGINT
Restart=on-failure
RestartSec=20
SyslogIdentifier=Node-RED

[Install]
WantedBy=multi-user.target

at least it works for me!