Dynamic routes on Cloudflare fail trying to import node:fs/promises

[rmarscher]

The error in the workerd console is

Cannot process SSR Error: No such module "node:fs/promises".
    at null.<anonymous> (file:///waku-project/.wrangler/tmp/pages-tQnVbB/entries.js:485:11)

That is referencing these changed lines in #860. Before that PR, Cloudflare workerd must have been getting routing information from unstable_buildConfig[0].customData.data.

To reproduce
npm create waku@0.9.3
cd waku-project
npm install

Then edit src/pages/about.tsx and change getConfig to dynamic:

export const getConfig = async () => {
  return {
    render: 'dynamic',
  };
};

Clone the waku repo.
cd packages/waku
pnpm i
pnpm run compile

Copy or link the built package to the waku project. I just replace the dist folder in node_modules/waku/dist.

In the waku project, run a cloudflare build and run a local workerd server via wrangler to serve the built files locally.

npm run build -- --with-cloudflare
npx wrangler pages dev dist

open http://localhost:8788/about in your browser.

[tylersayshi]

For this we could definitely add logic into the fs-router and build process for --with-cloudflare to polyfill fs when dynamic routes are present.

I'll defer to @dai-shi on whether or not that's an ideal approach or not with this though. I haven't looked into the plugins a ton, but maybe this would be considered a responsibility of a cloudflare plugin.

[rmarscher]

Thanks for giving it a look. I'm not sure polyfilling fs is necessary... it seems the platformObject.buildData.fsRouterFiles should be populated. If the build process could pass the fsRouterFiles to the build output vite plugin, it could write to a source file during build that can be imported at runtime and added to the platformObject via the platform server.

For example, the platformObject here - https://github.com/dai-shi/waku/blob/main/packages/waku/src/lib/plugins/vite-plugin-deploy-cloudflare.ts#L86 - would need buildData.fsRouterFiles to be set. It could serialize that to a json file in the worker code bundle. That json file would be imported and passed to the waku server here https://github.com/dai-shi/waku/blob/main/packages/waku/src/lib/builder/serve-cloudflare.ts#L36-L38

[dai-shi]

Thanks for the catch. I'll have a look.