password             (string)    MQTT password
qos                  (number)    set the quality of service priority, defaults to '0'
keep_alive_interval  (duration)  keep-alive interval for MQTT connections in s,m,h,d
reconnect_interval   (duration)  reconnect interval for MQTT connections in s,m,h,d
queue_dir            (path)      staging dir for undelivered messages e.g. '/home/events'

		if err != nil {
			return nil, err
		}

		reconnectIntervalEnv := target.EnvMQTTReconnectInterval
		if k != config.Default {
			reconnectIntervalEnv = reconnectIntervalEnv + config.Default + k
		}
		reconnectInterval, err := time.ParseDuration(env.Get(reconnectIntervalEnv,
			kv.Get(target.MqttReconnectInterval)))
		if err != nil {
			return nil, err
		}

		keepAliveIntervalEnv := target.EnvMQTTKeepAliveInterval