Support for Rails 5.1 on App Engine: installing yarn on the Ruby runtime

[Rafael Soares]

So, I've created a new Rails 5.1 app, worked on it locally (even built some webpack modules) and deployed to App Engine Flex environment.

It worked nicely, but I saw this error message in the console output:

Step 8/10 : RUN if test -d app/assets -a -f config/application.rb; then       bundle exec rake assets:precompile || true;     fi

 ---> Running in 503bf8112b4a

Yarn executable was not detected in the system.

Download Yarn at https://yarnpkg.com/en/docs/install

/app/vendor/bundle/ruby/2.4.0/bin/rake: No such file or directory - yarn

It continued to finish the deploy, and the app worked normally, but I suspect that was because I ran `RAILS_ENV=production rails assets:precompile` locally before deploying (I was following the tutorial for deploying). It probably wouldn't have built the assets.

Is there a way (or is it on the roadmap) to install yarn on the ruby runtime, so we can leverage asset precompilation during deploy, avoiding the need to precompile locally.

Thanks!

[Kenworth (Google Cloud Platform)]

I am currently investigating this issue and will post on this thread when I have an update.

[Kenworth (Google Cloud Platform)]

Hi Rafael,

This is expected behavior at the moment. Our backline team is aware of the Yarn use-case issue and is working on it. You can consult this GitHub thread [1] for a similar issue. It discusses some possible workarounds like customizing the Dockerfile.

[1] https://github.com/GoogleCloudPlatform/ruby-docker/issues/91