Separate watch from nunjucks / 100% CPU Issues

Hi, the code below causes nunjucks to use 100% of one CPU core. It makes no difference if i use different template contents, different contexts or the asyc api.

Nunjucks version: 1.1.0 Node Version: v0.10.31

var nunjucks = require('nunjucks');

nunjucks.renderString('my template', {});

setTimeout(function(){}, 1000*3600);

[tyler-johnson]

In case anyone else is looking for a temporary workaround, this is what I am using:

var nunjucks = require("nunjucks");
var chokidar = require("chokidar");

function configureNunjucks(paths, options) {
  var loader = new nunjucks.FileSystemLoader(paths, true);

  var watcher = chokidar.watch(loader.searchPaths, {
    ignoreInitial: true,
    usePolling: false,
    useFsEvents: true
  });

  watcher.on("all", function(event, fullname) {
    if (event == "change" && fullname in loader.pathsToNames) {
      loader.emit('update', loader.pathsToNames[fullname]);
    }
  });

  return new nunjucks.Environment(loader, options);
}

// to use:
var env = configureNunjucks("./views", { autoescape: true });

[jlongster]

The CPU issue looks to be fixed after upgrading to a much better version of chokidar: https://github.com/mozilla/nunjucks/pull/405

I’ve been working on separate the watcher, but I’m not entirely sure it’s a great idea anymore. Technically it’s just hard – how do I take a watcher from the user and use it? The only way to do this is to standardize an interface and force the user to load in a watcher compatible with it and install it. That’s just too much work in my opinion for a feature that should be builtin.

What I think we can do is support multiple watchers. If someone wants to make a PR to take a watcher option that specifies either chokidar or some other watcher, I would be open to it