Add PNPM support

[cyrillesondag]

Hello,

Within my company, we use pnpm to improve download times for Node.js dependencies. Unfortunately, there is currently no support for this package manager available for paketo-buildpacks.

Have you considered implementing this functionality ?

If this might interest you, I have started working on an implementation based on the pack made for Yarn that is available here: cyrillesondag/paketo-buildpacks-pnpm

Please feel free to share your feedback if you would like me to continue in this direction.
Best regards,

[dmikusa]

@paketo-buildpacks/nodejs-maintainers

[pacostas]

Hello @cyrillesondag Good idea :) Both npm and yarn are supposed to be a drop in replacement of npm and I think in terms of feature parity pretty much are the same, or at least have the same differences in comparison to npm.

I think for supporting pnpm, two parts are needed, the pnpm bulidpack (the one that you currently working on) and the pnpm-install.
For the pnpm this seems to be the way to go, by forking the yarn.

For the pnpm-install, I would suggest going with a fork from npm-install, as npm-install has much more fixes the recent years, as a result more edge cases are covered which will lead to less maintenance and issues in the future. Also, in terms of testing/test coverage, npm-install has almost double the tests, which is something we relying a lot on each release for catching any potential issues each time we introduce a new node version, builder, etc.. Of course you will need some parts from yarn-install to adopt on pnpm-install, as pnpm is an additional package manager similar to what yarn is.

[cyrillesondag]

Hi @pacostas, thanks for your reply.

While working on the PNPM buildpack, I'm encountering some issues with dependency resolution.
Most dependencies are packaged as archives, which works well with libpack. However, PNPM is packaged as a binary (at least in the official GitHub repository), so I'm a bit stuck with libpack because I haven't found a good way to handle this case properly.

I'll give libcnb a try—it seems to handle this scenario better (though it does introduce a Syft dependency).

[pacostas]

Hello @cyrillesondag !

Looking at your implementation, I think you are using jam for packaging https://github.com/cyrillesondag/paketo-buildpacks-pnpm/blob/c3b5299f2b27f7c2e69503167cd05aa60099c80a/scripts/package.sh#L133

Under nodejs buildpacks, the only buildpack that has dependencies is the node-engine https://github.com/paketo-buildpacks/node-engine/blob/main/buildpack.toml so it might be helpful looking at the node-engine project structure, practically the .github and the scripts directories.
Also, I think is a good idea to use jam instead of libpack, as we are also doing an effort in converting all nodejs buildpacks to multi-arch (some of them are already supporting it e.g. npm-install ) That way will be much easier to also transfom pnpm to multi-arch, as we already have done a lot of progress towards multi-arch based on the project structure that node-engine follows. We have also merged the multi-arch implementation on github-config paketo-buildpacks/github-config#1148

[cyrillesondag]

You're perfectly wright !
I completely missed that part.

Thanks!