Webpacker: Compile as part of `rails assets:precompile`.

[cgarvis]

We were using ReactOnRails before trying Webpacker. In order to get Heroku to compile the assets I had to add the following rake task.

Rake::Task['assets:precompile']
  .clear_prerequisites
  .enhance(['assets:compile_environment'])

namespace :assets do
  # In this task, set prerequisites for the assets:precompile task
  task compile_environment: :webpack do
    Rake::Task['assets:environment'].invoke
  end

  desc 'Compile assets with webpack'
  task :webpack do
    sh 'bundle exec rails webpacker:compile'
  end
end

Anyway we can make this part of webpacker?

[dhh]

Yes, we should definitely make compilation part of the default package for
assets:precompile.

On Thu, Dec 29, 2016 at 7:23 AM, Christopher Garvis <
[email protected]> wrote:

We were using ReactOnRails before trying Webpacker. In order to get Heroku
to compile the assets I had to add the following rake task.

Rake::Task['assets:precompile']
.clear_prerequisites
.enhance(['assets:compile_environment'])

namespace :assets do
# In this task, set prerequisites for the assets:precompile task
task compile_environment: :webpack do
Rake::Task['assets:environment'].invoke
end

desc 'Compile assets with webpack'
task :webpack do
sh 'bundle exec rails webpacker:compile'
endend

Anyway we can make this part of webpacker?

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[puneet-sutar]

@cgarvis Did you also edit the heroku-ruby-buildpack to install node and yarn ? Or are you using some other solution.

I am using webpacker + react
I had to fork the heroku-ruby-buildpack and add code to do the following:

• Install node.
• Install yarn.
• Install node packages using yarn.
• run the webpacker:compile

If the package.json and yarn.lock files were in the root folder(instead of vendor) I could have just used the https://github.com/heroku/heroku-buildpack-nodejs#yarn which would have installed the packages for me and then added the code you have posted above in my codebase.

Thanks in advance for you help!

[cgarvis]

@puneet-sutar I have multiple build packs heroku/ruby and heroku/nodejs. I have a fake package.json and yarn.lock file at the root level.

[audionerd]

@cgarvis Are your fake package.json and yarn.lock at root level exact copies of those in vendor?

[cgarvis]

No.

package.json

{}

yarn.lock

# trick heroku into installing yarn

[audionerd]

Thanks @cgarvis.

I tried that approach, but got this error:

    remote: -----> Preparing app for Rails asset pipeline
    remote:        Running: rake assets:precompile
    remote:        bundle exec rails webpacker:compile
    remote:        sh: 1: ./node_modules/webpack/bin/webpack.js: not found
    remote:        rails aborted!

I'm guessing this is because yarn never ran in the vendor folder, so vendor/node_modules was empty when webpacker:compile was called.

[audionerd]

The following worked for me:

In root Rails app folder:

package.json

{
  "name": "app-name-here",
  "description": "dummy package.json for heroku/nodejs buildpack support",
  "private": true,
  "engines": {
    "node": "6.5.0",
    "yarn": "0.18.1"
  },
  "scripts": {
    "heroku-postbuild": "cd vendor && yarn"
  }
}

yarn.lock

# Dummy yarn.lock to force heroku/nodejs to install yarn

Then add the nodejs buildpack first, before ruby buildpack:

$ heroku buildpacks:add --index 1 heroku/nodejs

Deploy

$ git push heroku master

Caveats:

• This creates an extra unused node_modules folder in Rails root when the Heroku nodejs buildpack runs the dummy install.
• Heroku was confused when I added the nodejs buildpack to an existing Heroku app. Had to add/re-add ruby buildpack. Possibly a fluke with my config. https://devcenter.heroku.com/articles/buildpacks#detection-failure

[puneet-sutar]

@cgarvis @audionerd Nice tricks.

I had tried the fake package.json + yarn.lock + patching rake task to run bin/yarn install and web:compile approach works nicely.

I have also forked the heroku-ruby-buildpack and using it in my project now. If you want to give it a shot https://github.com/puneet-sutar/heroku-buildpack-ruby. Trying to get it merged(https://github.com/heroku/heroku-buildpack-ruby/pull/521).

With this you just need 1 buildpack and don't need an fake files or patching tasks. It will do the following:

1. Detect presence of vendor/yarn.lock and vendor/package.json
2. If above files are present the download and install appropriate version of yarn an package.json(you can specify version as engines in package.json).
3. Install node_modules bin/yarn install
4. Run rake webpacker:compile

[audionerd]

Ah, I see – definitely makes more sense to run yarn via that rake task vs in heroku-postbuild. Like this example:
https://github.com/gauravtiwari/rails-webpacker/blob/master/lib/tasks/assets.rake

That patch looks great. It would be so nice to have yarn installed by the Heroku ruby buildpack.
Not sure if it should be responsible for calling webpacker:compile though, if it's easy enough to hook that into the existing assets:precompile.

[puneet-sutar]

@audionerd Just did not want to patch my rails App. Can always remove the webpacker:compile once webpacker adds it to assets:precompile.

[codebryo]

Not sure if this still helps, but for getting it running on Heroku, I did following:

• Set Buildpacks heroku/nodejs & heroku/ruby
• Create a fake yarn.lock ( Thanks for the tip @cgarvis )
• Extend the Rakefile with:

Rake::Task['assets:precompile'].enhance do
  system('bundle exec ./bin/yarn')
  system('bundle exec rails webpacker:compile')
end

as I locally run the Rails app through foreman or in a Docker container I don't use the Rakefile elsewhere.
Will not be necessary anymore if both steps wander into the assets precompile step anyway :)

[merqlove]

Seems that yarn bug is fixed in master version.
I'm think different now, because i won't recompile packs from the outside of the current engine, so i decide to precompile it & and release within public/dist folder. So any app that uses current engine can pick it up without dependencies 💩.

[dhh]

Fixed:

• Yarn before assets:precompile
• Webpack after assets:precompile

[schneems]

We are working on adding yarn to the buildpack for Rails right now on Heroku, so it won't work yet because we don't have the binaries in place.

[benbonnet]

Admitting you already have the npm modules installed, how one could still use assets:precompile with the ability to remove the yarn command ? Just keep the effective build (the rails one and the webpack(er) one)