@droneblocks/node-red-dexi/src/ros2-subscribe.js

You want to make sure you don't lose any of your flow development. Make sure to map the host "flows" directory to the container directory as shown below. This will store the flow on your host machine if/when the container is destroyed.

module.exports = function (RED){
    var ROSLIB = require('roslib')

    function ROS2SubscribeNode(config) {
      RED.nodes.createNode(this, config);
      var node = this;

      node.server = RED.nodes.getNode(config.server);

      if (!node.server || !node.server.ros){
        return;
      }

      node.closed = false;

      // if topic has not been advertised yet, keep trying again
      function topicQuery(topic){
        if (node.closed){ return; }

        node.server.ros.getTopicType(topic.name, (type) => {
          if (node.closed){ return; }

          if (!type){
            node.status({fill:"yellow", shape:"ring", text:"waiting for topic"});
            node.tout = setTimeout(()=>{topicQuery(topic)}, 1000);
          } else {
            topic.subscribe(function(data){
              var o = JSON.parse(JSON.stringify(data))
              node.send({payload: o});
            });
            node.status({fill:"green", shape:"dot", text:"subscribed"});
          }
        })
      }

      function subscribe(){
        // A reconnect calls this again; drop any retry still pending from the
        // previous connection so the 1s loops don't accumulate.
        if (node.tout) { clearTimeout(node.tout); node.tout = null; }

        node.topic = new ROSLIB.Topic({
          ros : node.server.ros,
          name : config.topicname
        });

        topicQuery(node.topic);
      }

      node.server.on('ros connected', subscribe);

      // The server can already be connected when this node is created - a
      // deploy of modified nodes only does not restart the config node, so
      // 'ros connected' has already fired and will not fire again.
      if (node.server.ros.isConnected){
        subscribe();
      } else {
        node.status({fill:"grey", shape:"ring", text:"connecting"});
      }

      node.server.on('ros error', () => {
        node.status({fill: "red", shape:"dot", text:"error"});
      });

      node.on("close", function() {
        node.closed = true;
        if (node.tout) { clearTimeout(node.tout); }
        if (node.topic && !node.server.closing){
          node.topic.unsubscribe();
        }
      });
    }

    RED.nodes.registerType("ros2-subscribe", ROS2SubscribeNode);
  };