Can't deploy with Kamal after install esbuild

[sbleon]

After installing this gem and using it to install esbuild, the build stage of the Dockerfile doesn't have the tools needed to precompile assets. Here's the error I got:

 [build 6/6] RUN SECRET_KEY_BASE_DUMMY=1 ./bin/rails assets:precompile
 1.342 bin/rails aborted!
 1.342 jsbundling-rails: Command install failed, ensure yarn is installed
 1.370 
 1.370 Tasks: TOP => assets:precompile => javascript:build => javascript:install
 1.370 (See full trace by running task with --trace)
 ERROR: process "/bin/sh -c SECRET_KEY_BASE_DUMMY=1 ./bin/rails assets:precompile" did not complete successfully: exit code: 1

I was able to resolve this issue by adding the following to the build stage of the Kamal-generated Dockerfile after the apt-get install build-essential step.

RUN curl -fsSL https://deb.nodesource.com/setup_20.x -o nodesource_setup.sh && \
    bash nodesource_setup.sh
RUN apt-get install -y nodejs
RUN npm install --global yarn

I don't know if this is something that is generalizable, or if it is needed for all of the various bundlers. But, I suspect that other folks will run into this error and might not have the Docker knowledge needed to fix it.

[dhh]

Not a lot we can do about that. If you generate a new Rails 8 app and you say you want esbuild, that is configured for you. But otherwise this is something you have to do by yourself. Possible we could add something to an FAQ though. Feel free to explore that!

[sbleon]

Thanks, @dhh. I think adding a note to the FAQ would go a long way. Would it be totally crazy to have the javascript:install rake task check for the presence of Kamal and have it output a message like the following?

Kamal detected. See the FAQ for deployment config instructions.
https://github.com/rails/jsbundling-rails?tab=readme-ov-file#faq

[dhh]

Happy to consider a PR! All depends on how invasive it feels etc.