How to stop recording by camera node through an user input?

edit

I would like to stop the camera node through a different node. I was trying to implement this by sending a message through another node which is read by the camera node But, the problem is that the camera node runs on an infinite loop. Can I get a cpp implementation to stop this while loop through a subscribed message.

#include <ros/ros.h>
#include <image_transport/image_transport.h>
#include <opencv2/highgui/highgui.hpp>
#include <cv_bridge/cv_bridge.h>
#include <sstream> // for converting the command line parameter to integer
#include "std_msgs/Int32.h"

bool camOn = true;


void sendCamera(const std_msgs::Int32::ConstPtr& msg)
{
   if (msg->data == 1){
    camOn = true;}
   else if (msg->data == 2){
    camOn = false;}
}

int main(int argc, char** argv)
{


  ros::init(argc, argv, "image_publisher");
  ros::NodeHandle nh;
  ros::Subscriber sub = nh.subscribe("/camera_status", 1000, sendCamera);
  image_transport::ImageTransport it(nh);
  image_transport::Publisher pub = it.advertise("camera/image", 1);


  cv::VideoCapture cap(0);
  if(!cap.isOpened()) return 1;
  cv::Mat frame;
  sensor_msgs::ImagePtr msg;

  ros::Rate loop_rate(10);
    while(nh.ok()){
      while (camOn) {
        ros::Subscriber sub = nh.subscribe("/camera_status", 1000, sendCamera);
        cap >> frame;
        // Check if grabbed frame is actually full with some content
        if(!frame.empty()) {
          msg = cv_bridge::CvImage(std_msgs::Header(), "bgr8", frame).toImageMsg();
          pub.publish(msg);
          cv::waitKey(1);
        }

        ros::spin();
        loop_rate.sleep();
    }    
  }
}