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ruby-on-railsherokuwebpackwebpacker

Error precompiling assets while deploying to Heroku with webpack

I have a project that I've recently upgraded to rails 5.2, and I'm using the webpacker gem. I get the following error trying to deploy to Heroku:

...
remote:        Webpacker is installed 🎉 🍰
remote:        Using /tmp/build_b969a2366f45a65a0c09b6aaa4b24667/config/webpacker.yml file for setting up webpack paths
remote:        Compiling…
remote:        Compilation failed:
remote:        /tmp/build_b969a2366f45a65a0c09b6aaa4b24667/vendor/bundle/ruby/2.5.0/gems/webpacker-3.5.5/lib/webpacker/webpack_runner.rb:11:in `exec': No such file or directory - /tmp/build_b969a2366f45a65a0c09b6aaa4b24667/node_modules/.bin/webpack (Errno::ENOENT)
remote:         from /tmp/build_b969a2366f45a65a0c09b6aaa4b24667/vendor/bundle/ruby/2.5.0/gems/webpacker-3.5.5/lib/webpacker/webpack_runner.rb:11:in `block in run'
remote:         from /tmp/build_b969a2366f45a65a0c09b6aaa4b24667/vendor/bundle/ruby/2.5.0/gems/webpacker-3.5.5/lib/webpacker/webpack_runner.rb:10:in `chdir'
remote:         from /tmp/build_b969a2366f45a65a0c09b6aaa4b24667/vendor/bundle/ruby/2.5.0/gems/webpacker-3.5.5/lib/webpacker/webpack_runner.rb:10:in `run'
remote:         from /tmp/build_b969a2366f45a65a0c09b6aaa4b24667/vendor/bundle/ruby/2.5.0/gems/webpacker-3.5.5/lib/webpacker/runner.rb:6:in `run'
remote:         from ./bin/webpack:15:in `<main>'
...

Locally my 'node_modules' directory is in .gitignore (I believe one of the webpacker install scripts put it there).

Do I need to un-ignore node_modules, or is there something I need to add to the config file to tell the remote where to find webpack?

Here's my package.json:

{
  "dependencies": {
    "@rails/webpacker": "3.5.5",
    "babel-preset-react": "^6.24.1",
    "d3": "^5.7.0",
    "jquery": "^3.3.1",
    "prop-types": "^15.6.2",
    "react": "^16.5.2",
    "react-addons-transition-group": "^15.6.2",
    "react-dom": "^16.5.2",
    "react-transition-group": "^2.4.0",
    "react_ujs": "^2.4.4"
  },
  "devDependencies": {
    "webpack-dev-server": "2.11.2"
  },
  "engines": {
    "yarn": "1.10.1"
  } 
}

I noticed the output from heroku mentioned setting up webpacker paths using config/webpacker.yml, but I can't find any mention in that file of looking for webpack in node_modules - here is the text of webpacker.yml:

# Note: You must restart bin/webpack-dev-server for changes to take effect

default: &default
  source_path: app/javascript
  source_entry_path: packs
  public_output_path: packs
  cache_path: tmp/cache/webpacker

  # Additional paths webpack should lookup modules
  # ['app/assets', 'engine/foo/app/assets']
  resolved_paths: []

  # Reload manifest.json on all requests so we reload latest compiled packs
  cache_manifest: false

  extensions:
    - .jsx
    - .js
    - .sass
    - .scss
    - .css
    - .module.sass
    - .module.scss
    - .module.css
    - .png
    - .svg
    - .gif
    - .jpeg
    - .jpg

development:
  <<: *default
  compile: true

  # Reference: https://webpack.js.org/configuration/dev-server/
  dev_server:
    https: false
    host: localhost
    port: 3035
    public: localhost:3035
    hmr: false
    # Inline should be set to true if using HMR
    inline: true
    overlay: true
    compress: true
    disable_host_check: true
    use_local_ip: false
    quiet: false
    headers:
      'Access-Control-Allow-Origin': '*'
    watch_options:
      ignored: /node_modules/


test:
  <<: *default
  compile: true

  # Compile test packs to a separate directory
  public_output_path: packs-test

production:
  <<: *default

  # Production depends on precompilation of packs prior to booting for performance.
  compile: false

  # Cache manifest.json for performance
  cache_manifest: true

The entire project can be found on github

Solution

  • I finally resolved this issue by rebuilding the /bin directory using the following:

    rails app:update:bin

    I reasoned that I must have corrupted something in that directory. I had started the project using the rails-jquery and rails-react gems and then used the webpacker install scripts to install jquery and react. I decided to use yarn add ... to add jquery and rails so I could manage my dependencies more tightly and consistently with yarn.