Using Heroku Scheduler with Node.js

Question

There is literally no tutorial about using Heroku Scheduler with Node.js. Assume that I have a function called sayHello() and I would like to run it every 10 mins. How can I use it in controller. In ruby you write rake function_name() however no explanation made for Node. Can I write '/sayHello' or I should do extra configuration?

Answer 1

Create the file <project_root>/bin/say_hello:

#! /app/bin/node
function sayHello() {
  console.log('Hello');
}
sayHello();
process.exit();

Deploy to Heroku and test it with $ heroku run say_hello then add it to the scheduler with task name say_hello.

Explanation

Take say_hello.js as an example of a Node.js script that you would normally run using $ node say_hello.js.

Turn it into a script by

1. removing the .js ending
2. inserting the 'shebang' at the top: #! /app/bin/node [1][2]
3. moving it into the bin directory [3]

[1] Read about the shebang on Wikipedia.
[2] The node executable is installed in app/bin/node on Heroku. You can check it out by logging into bash on Heroku with $ heroku run bash then asking $ which node.
[3] Heroku requires scripts to be placed in the bin directory. See Defining Tasks in the Heroku Dev Center.

I agree that the Heroku documentation for scheduling tasks is not very clear for anything other than Ruby scripts. I managed to work it out after some trial and error. I hope this helps.