Start Service with Sudo

Question

I am trying to run an Express API server with sudo permissions and have it automatically start on boot.

The API needs access to bcm2835 library, and I get the following when trying to run node server.js

bcm2835_init: Unable to open /dev/mem: Permission denied /home/pi/Documents/node_modules/rpio/lib/rpio.js:104 return bindfunc(optarg);

Error: Could not initialize bcm2835 library
at bindcall (/home/pi/...) etc.

However it boots up fine running sudo node server.js.

I have created a service file at /etc/systemd/system as follows:

[Unit]
Description=Node API
After=network.target

[Service]
ExecStart=/usr/bin/node /home/pi/Documents/server.js
Restart=always
SyslogIdentifier=controller
User=root
Group=root
Environment=

TimeoutStopSec=30

[Install]
WantedBy=multi-user.target

I found some guidance here and here, but they seem slightly off, since a sub-command needs sudo/root privileges.

How can I run this service with proper permissions so it boots up with the Pi?

I think the boot is failing silently in the background.

Answer 1

/dev/mem must be run as root, so after a fresh install of Raspbian.

1. Create the service

2. Enable the service with systemctl enable nameOfService