[Unit]
Description=Crystal estimation worker
After=network.target

[Service]
Type=simple
User=www-data
Group=www-data
# The repo lives in crystal2/, not crystal/ — the previous paths here pointed at
# a directory that does not exist, so the unit could never have started.
WorkingDirectory=/var/www/html/crystal/crystal2
ExecStart=/usr/bin/python3 /var/www/html/crystal/crystal2/worker/worker.py
Restart=always
RestartSec=5
# journald rather than a file in /var/log: the service runs as www-data, and a
# log path it cannot create is a service that will not start.
#   journalctl -u crystal-worker -f
StandardOutput=journal
StandardError=journal

[Install]
WantedBy=multi-user.target