Enable cache directory path to be set explicitly

[fwouts]

Changes

This enables the cache directory, which is by default node_modules/.cache/snowpack, to be set explicitly via CLI flag or configuration. This can be useful in situations where, for example, you are running Snowpack for a project that isn't in the current working directory.

Example usage

CLI

snowpack dev --cache-dir-path .snowpack-cache

API

await snowpack.startServer({
  config: snowpack.createConfiguration({
    buildOptions: {
      cacheDirPath: path.join(__dirname, ".snowpack-cache"),
    },
    ...
  }),
  lockfile: null,
});

Testing

This is simply piping through configuration values. Happy to add a test, but I'm not sure it's needed :)

Docs

There doesn't seem to be explicit documentation for every CLI flag at this stage, so no documentation was added.

[vercel]

This pull request is being automatically deployed with Vercel (learn more).
To see the status of your deployment, click below or on the icon next to each commit.

🔍 Inspect: https://vercel.com/pikapkg/snowpack/DZtXhuAtNyNJZ6JR11y3PcHaYHKE
✅ Preview: https://snowpack-git-fork-fwouts-custom-cache-dir-pikapkg.vercel.app

[FredKSchott]

Nice!!! I'm actually just getting ready to merge #3028 which changes some of this behavior. I'd love to add this support after that gets merged (I'll help rebase if there are any conflicts).

[fwouts]

No worries at all, I'm happy to take care of merge conflicts. Good opportunity to get more familiar with the codebase!

[fwouts]

@FredKSchott merge conflict is dealt with :)

[fwouts]

By the way, I noticed that Snowpack is noticeably slower since #3028 was merged. On a relatively simple project (slow-storybook branch in this repo), it went from 24 seconds to prepare the cache on the previous commit (aa1de0b), to 82 seconds (commit 25ed288). I noticed it hasn't been released yet, so it's probably a known issue. Happy to file one otherwise!

[drwpow]

This looks good to me! Only one last request before merging: we actually do have information on CLI flags if you run snowpack --help. Can you add this in there (snowpack/src/index.ts)? Then we can merge & ship this.

[drwpow]

Also please add documentation for this here, as well: https://www.snowpack.dev/reference/configuration#buildoptions

[drwpow]

I like this deterministic hash approach 👍🏻

[drwpow]

@fwouts I was not aware of that. Taking a look at that reproduction now.

[drwpow]

@fwouts you‘re right—the recent changes really do slow down the streaming builds 😕. That’s definitely worth opening up an issue about if you have time to.

[fwouts]

@fwouts you‘re right—the recent changes really do slow down the streaming builds 😕. That’s definitely worth opening up an issue about if you have time to.

Sorry! I no longer use Snowpack so I may not be in the best position to follow up on this 😶 I will of course address the feedback on the current PR to get it in a mergeable state though!