NodeJS and script hangs

[VectraMan]

Detecting that a program will run forever is known as the Halting Problem, and a certain Mr Alan Turing demonstrated quite a while ago that it's mathematically impossible to do so for the general case.

So yes, don't write code that runs forever if you can help it

Though it's relatively simple to have a different thread monitor the execution and if it doesn't get back to the event loop in a certain time, kill the script. This is what browsers do, so I'm a little surprised not to find it in Node.

And because of the obsessively event driven single threaded nature of Node one connection can always affect everything else. It doesn't even need to be a bug: one thing that takes too long will stop it responding to all requests.

I started my career doing software for Windows 3.1 so I'm well aware of the problems ;-) I didn't think I'd be doing it again, but that's progress for you.

For a detailed examination of strategies for error and exception handling in Node, with particular reference to the case of using it in an HTTP server, have a look at Error Handling in Node.js.

Thanks, that's very useful.

[NickFitz]

Detecting that a program will run forever is known as the Halting Problem, and a certain Mr Alan Turing demonstrated quite a while ago that it's mathematically impossible to do so for the general case.

So yes, don't write code that runs forever if you can help it

For a detailed examination of strategies for error and exception handling in Node, with particular reference to the case of using it in an HTTP server, have a look at Error Handling in Node.js.

[VectraMan]

I've been experimenting with Node JS and I was wondering what would happen if the script gets stuck in a loop. I.e. while(true);

I'll tell you what happens: it keeps running that loop; running one core at 100% until the end of time and stops responding to any events, even if they come from other clients/IPs (assuming Node is running a webserver that is). Basically a dead server because of one script bug, which strikes me as quite poor.

The other less than ideal thing I've discovered is that (by default at least) runtime errors result in it calling exit(), which again takes down the whole server rather than just the one connection.

What do people who use NodeJS for serious stuff do? Or is it a case of don't write code with bugs in it?