[Unit]
Description=preseed file generator
Documentation=https://www.npmjs.com/package/preseed
Requires=network.target
After=network.target

AssertFileNotEmpty=/etc/preseed/config.json

[Service]
User=daemon
WorkingDirectory=/etc/preseed

ExecStartPre=+-/usr/bin/env npm install --global preseed
ExecStart=/usr/bin/env preseed -c config.json

[Install]
WantedBy=multi-user.target

## place this file at /etc/systemd/system/preseed.service
## install dependencies and create config files
# npm install --global preseed
# mkdir /etc/preseed
# cp /usr/local/lib/node_modules/preseed/config-example.json /etc/preseed/config.json
# chown -vR daemon /etc/preseed

## Update config file

# systemctl enable preseed
# systemctl start preseed