feat: allows to skip node installation

[pftg]

In order to use Bun with Rails, will be great to avoid redundant Node and Yarn installations.

[pftg]

@edmorley @schneems hey guys, could you review this PR

[nertzy]

I have a similar use case. We pre-build our assets as part of our CI pipeline and then push with heroku builds:create. This buildpack then still insists on installing a Node runtime that is not used as part of the Heroku build process.

[edmorley]

(Switching code review request from the Languages team alias to the Ruby language owner)

[schneems]

In order to use Bun with Rails, will be great to avoid redundant Node and Yarn installations.

I'm unfamiliar with bun, looking now. I found https://medium.com/nyc-ruby-on-rails/what-is-bun-d343601fed77 which is paywalled. I found https://bun.sh/. It looks like it's an alternative Node runtime like Deno which is written in Rust https://github.com/denoland/deno. I'm not clear on how it gets installed into a Ruby app or why.

I found rails/rails#49241 linked from Ruby weekly.

You can create a new app like this:

$ mkdir -p /tmp/ecdb467647e9cb8b6dad2775d6eda59f; cd /tmp/ecdb467647e9cb8b6dad2775d6eda59f
⛄️ 3.1.4 🚀 /tmp/ecdb467647e9cb8b6dad2775d6eda59f
⛄️ 3.1.4 🚀 /tmp/ecdb467647e9cb8b6dad2775d6eda59f
$ rails new my_app  --javascript bun --css tailwind --database sqlite3

But then I'm unable to get it to build assets:

$ rake assets:precompile
yarn install v1.22.19
[1/4] 🔍  Resolving packages...
success Already up-to-date.
✨  Done in 0.04s.
yarn run v1.22.19
error Command "build" not found.
info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.
rake aborted!
jsbundling-rails: Command build failed, ensure `yarn build` runs without errors
/Users/rschneeman/.gem/ruby/3.1.4/gems/jsbundling-rails-1.2.2/lib/tasks/jsbundling/build.rake:14:in `block (2 levels) in <main>'
/Users/rschneeman/.gem/ruby/3.1.4/gems/rake-13.1.0/exe/rake:27:in `<top (required)>'
Tasks: TOP => assets:precompile => javascript:build
(See full trace by running task with --trace)

Here's the full rails output https://gist.github.com/schneems/33ae9ace6b120e363a107ef9a8014b54

I'm unclear on how bun is installed on Heroku or how it's invoked. If it's a node runtime then which node should return a zero exit code indicating it's already installed and doesn't need to be reinstalled. If you don't need yarn installed you can delete the yarn.lock file and we won't install it, or alternatively provide a bin/yarn executable which will return zero on which yarn.

It looks like via https://bun.sh/docs/quickstart it doesn't give you a node shim but gives you a new command bun. you could create your own bin/node that redirects arguments to bun and that would also short-circuit our installing node logic.

I found oven-sh/bun#559 but there's not a single recommended way to install it on Heroku.

It's worth noting that in the future we'll be moving away from installing node and yarn and leaving that up to the node buildpack. This is in our CNB, which cannot be used right now https://github.com/heroku/buildpacks-ruby.

[schneems]

I don't think I'll be merging this as it's not a feature I'll be able to forward port to the CNB and there are already mechanisms for avoiding installing those binaries. I think that which node and which yarn along with package.json and yarn.lock files are strong interfaces that we should rely on instead.

If you need help getting bun to work on a Heroku app, please open a support ticket and I can take a look. I can't write a custom buildpack, but I know a lot about buildpacks and could help someone who is interested.

[pftg]

Hey @schneems, thanks for the review.

I do not have any issue installing bun, I have a build pack for this https://github.com/jetthoughts/heroku-buildpack-bun

It looks like via https://bun.sh/docs/quickstart it doesn't give you a node shim but gives you a new command bun. you could create your own bin/node that redirects arguments to bun and that would also short-circuit our installing node logic.

yep, one of the options

Overall, there was no problem installing the bun; the problem was to prevent the installation of nodes and yarn. I'll check your options with stubbing node. Based on the code run("which node").strip, it should work.