NPM doesn't install module dependencies when deploying a Grunt app to heroku

Question

I'v made a static single page site using grunt. I'm now trying to deploy it to heroku using the heroku-buildpack-nodejs-grunt for node grunt.

Below is a pic of my root directory:

Here's my Gruntfile package.json:

Procfile:

web: node index.html

When I run $ git push heroku master it gets to the Gruntfile and fails:

-----> Found Gruntfile, running grunt heroku:production task
>> Local Npm module "grunt-contrib-uglify" not found. Is it installed?

The above errors proceed to list all local NPM modules as not found. If I list all loadNpmTasks instead of using "load-grunt-tasks", I get the exact same error.

When I $ heroku logs I get:

Starting process with command `node web.js`
Error: Cannot find module '/app/web.js'

Can anyone see where I've gone wrong?

Answer 1

For anyone passing by here, I wasn't able to solve the problem. This is where I got to:

In my Gruntfile, I moved npm modules from devDependencies to dependencies. Heroku was then able to install these dependencies.

However, when Heroku ran the tasks, it stops at the haml task w/ error "You need to have Ruby and Haml installed and in your PATH for this task to work". Adding ruby & haml to the Gruntfile as engines did not work.

Answer 2

The only thing I can think of is that maybe Heroku installs your devDependencies first, tries to run Grunt, but since it didn't install load-grunt-tasks yet, you don't get the grunt.loadNpmTasks( 'grunt-contrib-uglify' ); line (which load-grunt-tasks does for you), and thus Grunt can't find the package.

Can you try changing your Gruntfile to explicitly list out all npm modules using the grunt.loadNpmTasks() method?

EDIT:

Just remembered another thing I had to do:

heroku labs:enable user-env-compile -a myapp
heroku config:set NODE_ENV=production

(Obviously replacing myapp with your Heroku app name.)

This makes Heroku allow user set environment variables and then sets your server to production. Try that, and set your dependencies and devDependencies as you had them originally (just to see if it works).

Answer 3

I am coming pretty late to the game here but I have used a couple methods and thought I would share.

Option 1: Get Heroku to Build

This is not my favorite method because it can take a long time but here it is anyway.

Heroku runs npm install --production when it receives your pushed changes. This only installs the production dependencies.

You don't have to change your environment variables to install your dev dependencies. npm install has a --dev switch to allow you to do that.

npm install --dev

Heroku provides an article on how you can customize your build. Essentially, you can run the above command as a postinstall script in your package.json.

"scripts": {
  "start": "node index.js",
  "postinstall": "npm install --dev && grunt build"
}

I think this is cleaner than putting dev dependencies in my production section or changing the environment variables back and forth to get my dependencies to build.

Also, I don't use a Procfile. Heroku can run your application by calling npm start (at least it can now almost two years after the OP). So as long as you provide that script (as seen above) Heroku should be able to start your app.

As far as your ruby dependency, I haven't attempted to install a ruby gem in my node apps on Heroku but this SO answer suggests that you use multi buildpack.

Option 2: Deploy Your Dependencies

Some argue that having Heroku build your application is bad form. They suggest that you should push up all of your dependencies. If you are like me and hate the idea of checking in your node_modules directory then you could create a new branch where you force add the node_modules directory and then deploy that branch. In git this looks like:

git checkout -b deploy
git add -f node_modules/
git commit -m "heroku deploy"
git push heroku --force deploy:master
git checkout master
git branch -D deploy

You could obviously make this into a script so that you don't have to type that every time.

Option 3: Do It All Yourself

This is my new favorite way to deploy. Heroku has added support for slug deploys. The previous link is a good read and I highly recommend it. I do this in my automated build from Travis-CI. I have some custom scripts to tar my app and push the slug to Heroku and its fast.

Answer 4

I faced a similar problem with Heroku not installing all of my dependencies, while I had no issue locally. I fixed it by running

heroku config:set USE_NPM_INSTALL=true

into the path, where I deployed my project from. This instructs Heroku to install your dependencies using npm install instead of npm ci, which is the default! From Heroku dev center:

"Heroku uses the lockfiles, either the package-lock.json or yarn.lock, to install the expected dependency tree, so be sure to check those files into git to ensure the same dependency versions across environments. If you are using npm, Heroku will use npm ci to set up the build environment."