Heroku custom clock process fails to run at each interval using cron - node.js

Question

I'm not sure what I'm doing wrong, but I'm trying to follow this article. I have the following Procfile:
web: node index.js
worker: node bot.js
clock: node clock.js
and inside my clock.js, I have:
var CronJob = require('cron').CronJob;
var bot = require('./bot.js');
new CronJob({
cronTime: "* * * * *",
onTick: bot.start(),
start: true,
timeZone: "America/Los_Angeles"
});
and my bot.js is structured like so:
var config = require('./config');
// ... other includes
module.exports = {
start: function() {
// code
}
}
My structure matches the article pretty much exactly, but what's going on? Here are my logs:
2016-12-16T06:00:48.935847+00:00 heroku[web.1]: Starting process with command `node index.js`
2016-12-16T06:00:49.332925+00:00 heroku[worker.1]: Starting process with command `node bot.js`
2016-12-16T06:00:49.736519+00:00 heroku[clock.1]: Starting process with command `node clock.js`
2016-12-16T06:00:50.058125+00:00 heroku[worker.1]: State changed from starting to up
2016-12-16T06:00:50.395082+00:00 heroku[clock.1]: State changed from starting to up
2016-12-16T06:00:51.899971+00:00 app[web.1]: app running on port 21470
2016-12-16T06:00:52.505353+00:00 heroku[worker.1]: State changed from up to crashed
2016-12-16T06:00:52.491705+00:00 heroku[worker.1]: Process exited with status 0
2016-12-16T06:00:52.698864+00:00 heroku[web.1]: State changed from starting to up
So I can see that I'm starting up the worker (which does nothing) and it then crashes. Then my clock starts up , but never calls the worker again? It's definitely not starting up every minute.
Is the article I followed old and no longer applies? How should I correctly call the worker?

Answer 1

Do you have a process.exit(0) command somewhere in bot.start()?
Heroku crashes a dyno when it comes across the command (see this link for more info). If you remove that, it should potentially solve the problem. It would be helpful to post the full bot.start function to verify.