rules = [
  {"permit": "allow", "username": "grafana", "action": "subscribe", "topics": ["#"]}
  {"permit": "allow", "username": "grafana", "action": "publish", "topics": ["#"]}
  {"permit": "allow", "username": "admin", "action": "subscribe", "topics": ["#"]}
  {"permit": "allow", "username": "admin", "action": "publish", "topics": ["#"]}
  {"permit": "deny"}
]