Express.js webserver lasts 5 minutes on production before running out of memory

So I've got a Express.js server setup, but after about 5 minutes on production - http://balupton.com - it crashes and restarts.

The source code of my website is here: https://github.com/balupton/balupton.docpad/blob/master/server.coffee

The docpad reference it uses to create the server is here: https://github.com/bevry/docpad/blob/master/lib/docpad.coffee#L589

It's hosted on http://no.de and here is the out of memory exception that keeps appearing in the logs every 5 minutes or so:

FATAL ERROR: CALL_AND_RETRY_2 Allocation failed - process out of memory
[ Jul  7 14:02:13 Stopping because all processes in service exited. ]
[ Jul  7 14:02:13 Executing stop method (:kill). ]
[ Jul  7 14:02:13 Executing start method ("env `cat开发者_运维百科 /home/node/node-service/profile` /opt/nodejs/latest/bin/node /home/node/node-service/releases/20110707135409/server.js &"). ]
[ Jul  7 14:02:13 Method "start" exited with status 0. ]
Express server listening on port 80 and directory /home/node/node-service/releases/20110707135409/out

I've looked everywhere on this, but I've given up. Can anyone help me?

---

The problem turned out to be with the middlewares. Having the static middleware last meant that when a static file was not found, the static middleware would attempt to send the request to the next middleware - which didn't exist, so it would just keep the request open forever - so very quickly open connections started pilling up (due to spiders crawling non-existant urls) and would crash the server every time it ran out of resources.

The solution was to add a 404 middleware as the last middleware to run like so:

# 404 Middleware
myServerInstance.use (req,res,next) ->
    res.send(404)

This way, when the static middleware doesn't find a file, it sends it on to the next middleware, eventually the 404 middleware will be hit, and send off the 404 rather than keeping the request open forever.