if $programname == 'myapp' then {
    /var/log/myapp/myapp.log
    stop
}

[Unit]
Description=myapp

[Service]
User=myapp
ExecStart=/usr/bin/myapp
StandardOutput=syslog
StandardError=syslog
SyslogIdentifier=myapp

[Install]
WantedBy=multi-user.target

/var/log/myapp/myapp.log {
  rotate 7
  daily
  size 100MB
  compress
  missingok
  notifempty
  postrotate
    sudo systemctl restart rsyslog.service
  endscript
}