if err != nil {
			return nil, err
		}

		keepAliveIntervalEnv := target.EnvMQTTKeepAliveInterval
		if k != config.Default {
			keepAliveIntervalEnv = keepAliveIntervalEnv + config.Default + k
		}
		keepAliveInterval, err := time.ParseDuration(env.Get(keepAliveIntervalEnv,
			kv.Get(target.MqttKeepAliveInterval)))
		if err != nil {
			return nil, err
		}

		queueLimitEnv := target.EnvMQTTQueueLimit