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

		c.UpstreamConnectionOptions.TcpKeepalive.KeepaliveTime = &wrappers.UInt32Value{Value: uint32(keepalive.Time.Seconds)}
	}

	if keepalive.Interval != nil {
		c.UpstreamConnectionOptions.TcpKeepalive.KeepaliveInterval = &wrappers.UInt32Value{Value: uint32(keepalive.Interval.Seconds)}
	}
}

// Build a struct which contains service metadata and will be added into cluster label.