How to check the global file or directory against all deployed nodes?

Question

I'm working on an IoT application, where I have a node that keeps a list of what devices are connected to it that updates when a new message arrives.

For now I'm using the context to save the data, which is wiped on restart.

Using the node's id, I could save the list on a global JSON file, or have a file per node, but I run into a wall when it comes to maintenance.

Whenever I delete a node, its info is now trash. Is there a better way than to just check the global file or directory against all deployed nodes and delete what I don't need? And if there isn't, how do I get all current nodes?

Answer 1

Nodes have a on close callback which you could use to clean up when a node is deleted. Details can be found here

There are 2 versions of the callback, one that handles async actions and one that doesn't.

this.on('close', function(done) {
    doSomethingWithACallback(function() {
        done();
    });
});

and

this.on('close', function() {
    // tidy up any state
});