Systemctl Dynamic Path: AWS EC2 + AWS Linux2

[JJSagan]

Hi All,

The recommended setup for nvm/npm/nodejs is per user.

Lets assume you created a user nodebb, installed nodejs under it, and revised .bashrc to set environment variables to point to the latest version (standard procedure):
export NVM_DIR="$HOME/.nvm"
[ -s "$NVM_DIR/nvm.sh" ] && . "$NVM_DIR/nvm.sh" # This loads nvm
[ -s "$NVM_DIR/bash_completion" ] && . "$NVM_DIR/bash_completion" #

Systemctl expects full path to executable. Unfortunately, that path may change when nodejs gets updated.

So how do we hack systemctl to use a dynamic path?

1. Generate the env variables and dump them into a file
2. Load the file into systemctl environment

See config below:

[Unit]
Description=NodeBB Service
After=system.slice multi-user.target mongod.service syslog.target

[Service]
Type=idle
User=nodebb

StandardOutput=syslog
StandardError=syslog
SyslogIdentifier=nodebb

ExecStartPre=/bin/bash -c -l '/usr/bin/env > /tmp/tmp_env ; /bin/echo NODE_ENV=production >> /tmp/tmp_env'

EnvironmentFile=/tmp/tmp_env
WorkingDirectory=/path_to_nodebb

ExecStart=/usr/bin/env node loader.js --no-silent --no-daemon
Restart=always

[Install]
WantedBy=multi-user.target

Pay attention: Type=idle replaces Type=simple.

Good luck!
JJ.