Running Your Own Node.js Version on Heroku

UPDATE (3/3/12) – there’s a much easier way of doing this now – see ‘Specifying a version of Node.js / npm‘ in the Heroku Dev Center. The mechanism described below still works, but you should only go to all this trouble if you want something really custom.

Here’s a completely unofficial, unsupported recipe for running your own Node.js version on Heroku. These instructions are based on those at the Heroku Node.js Buildpack repository, with some extra steps that I found were necessary to make the process work. Note that buildpack support at Heroku is still evolving and the process will likely change over time. Please leave a comment if you try the instructions here and they don’t work – I’ll do my best to keep them up to date.

Before you start, update the heroku gem, so it recognizes the --buildpack option:

gem update heroku

(Thanks to ‘tester’ for leaving a comment reminding me that using an out of date heroku gem can result in the error message ! Name must start with a letter and can only contain lowercase letters, numbers, and dashes.)

Note: If you just want to try out a completely unofficial, unsupported Node.js 0.6.1 on Heroku, just create your app with my buildpack repository:

$ heroku create --stack cedar --buildpack http://github.com/metadaddy-sfdc/heroku-buildpack-nodejs.git

Otherwise, read on to learn how to create your very own buildpack…

First, you’ll need to fork https://github.com/heroku/heroku-buildpack-nodejs. Now, before you follow the instructions in the README to create a custom Node.js buildpack, you’ll have to create a build server (running on Heroku, of course!) with vulcan and make it available to the buildpack scripts. You’ll have to choose a name for your build server that’s not already in use by another Heroku app. If vulcan create responds with ‘Name is already taken‘, just pick another name.

$ gem install vulcan
$ vulcan create YOUR-BUILD-SERVER-NAME

Now you can create your buildpack. You’ll need to set up environment variables for working with S3:

$ export AWS_ID=YOUR-AWS-ID AWS_SECRET=YOUR-AWS-SECRET S3_BUCKET=AN-S3-BUCKET-NAME

Create an S3 bucket to hold your buildpack. I used the S3 console, but, if you have the command line tools installed, you can use them instead.

Next you’ll need to package Node.js and NPM for use on Heroku. I used the current latest, greatest version of Node.js, 0.6.1, and NPM, 1.0.105:

$ support/package_node 0.6.1
$ support/package_npm 1.0.105

Open bin/compile in your editor, and update the following lines:

NODE_VERSION="0.6.1"
NPM_VERSION="1.0.105"
S3_BUCKET=AN-S3-BUCKET-NAME

Now commit your changes and push the file back to GitHub:

$ git commit -am "Update Node.js to 0.6.1, NPM to 1.0.105"
$ git push

You can now create a Heroku app using your custom buildpack. You’ll also need to specify the Cedar stack:

$ heroku create --stack cedar --buildpack http://github.com/YOUR-GITHUB-ID/heroku-buildpack-nodejs.git

When you push your app to Heroku, you should see the custom buildpack in action:

$ cd ../node-example/
$ git push heroku master
Counting objects: 11, done.
Delta compression using up to 4 threads.
Compressing objects: 100% (8/8), done.
Writing objects: 100% (11/11), 4.02 KiB, done.
Total 11 (delta 1), reused 0 (delta 0)

-----> Heroku receiving push
-----> Fetching custom build pack... done
-----> Node.js app detected
-----> Fetching Node.js binaries
-----> Vendoring node 0.6.1
-----> Installing dependencies with npm 1.0.105

Dependencies installed
-----> Discovering process types
Procfile declares types -> web
-----> Compiled slug size is 3.3MB
-----> Launching... done, v6
http://strong-galaxy-8791.herokuapp.com deployed to Heroku

To git@heroku.com:strong-galaxy-8791.git
cd3c0e2..33fdd7a  master -> master
$ curl http://strong-galaxy-8791.herokuapp.com
Hello from Node.js v0.6.1

w00t!

Note: Due to an incompatibility between the default BSD tar on my Mac and GNU tar on Heroku, I saw many warnings while pushing my Node.js app to Heroku, of the form

tar: Ignoring unknown extended header keyword `SCHILY.dev'
tar: Ignoring unknown extended header keyword `SCHILY.ino'
tar: Ignoring unknown extended header keyword `SCHILY.nlink'

These are annoying, but benign – the push completes successfully. If you’re on a Mac and you want to get rid of them, add the line

alias tar=gnutar

just after the opening #!/bin/sh in both package scripts.