The poor man’s PHP daemon

We have this project lying around from a while back that’s based on PHP/AngularJS and also sports a socket.io server for (among other things) a real time chat. Pretty nifty (no, we didn’t do the design :)). The socket part is powered by a NodeJS process, and since we didn’t feel like (nor did the client have budget for) rewriting all our PHP code to Javascript, we used dNode-PHP (well, actually a fork with a few small project-specific adjustments) to let the Javascript code in the NodeJS process communicate with our existing PHP libraries. So now we had two processes which is suboptimal but worked at the time.

As a poor man’s solution (time pressure, limited budget, etc.) these processes were simply kept running in a permanent screen on the server. In theory, that worked well enough for then – the idea was that once the client found new budget, we’d finally properly daemonize them. And our server doesn’t reboot that often anyway, so remembering to restart the screen and processes on those occasions wasn’t a big deal.

Of course, that day never came.

There was however one annoying issue: PHP’s database resource would go stale after a while. According to the docs it should automatically reconnect, only it didn’t. This brought the need to manually restart those processes every once in a while (we put the MySQL timeout to a week to alleviate the burden, but the exact moment was random depending on the last moment of activity. Of course, one could argue that a site that’s completely inactive for >7 days regularly isn’t worth the effort, but a) that wasn’t our problem and b) the client was still working on his marketing plan. Fair enough).

Today I got fed up with it, had an hour to spare, and the marketing plan was ready as well. Time to bite the bullet; here’s what I came up with.

1. The NodeJS process

That part was easy; essentially I followed the instructions here. We don’t use Ubuntu but rather Debian, but it should be similar on all *nix systems.

2. The dNode-PHP process

This is where it got interesting, and which had been the actual bullet I’d been putting off biting. PHP isn’t very well suited to run as a daemon. It’s possible, but that doesn’t mean it’s desirable, in the same sense as writing out all your CSS in <script>document.write('<style>...<' + '/style>')</script> tags is only a theoretical option. But in this case it was still better than duplicating code in Javascript.

Now, there are ways to turn a PHP script into an actual daemon. It was still overkill for our purposes, so I simply went with a cronjob that killed any existing process and restarts it every hour. If the client ever needs an actual daemon, we’ll get to that then 🙂

Yes, this “daemon” is a beggar, but as they say: beggars can’t be choosers…

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