feat(cloudflare): generated wrangler configuration

[pi0]

Nitro has introduced an experimental (opt-in) way to generate/extend wrangler.toml for cloudflare deployments (#2353, #2355) (However, overwriting the user config is not ideal or recommended, so it remain experimental)

The end goal is to leverage Cloudflare platform features such as Node compat v2 (hybrid) and Async Context with zero-config and ensure we can reliably enable these features.

Thanks to the huge huge efforts and collab with the Cloudflare team and @petebacondarwin, a new solution (~> cloudflare/workers-sdk#7442) is coming to allow frameworks like Nitro to generate a merged wrangler.toml in dist and config that redirects/points wrangler CLI and pages CI to it.

Docs: https://developers.cloudflare.com/workers/wrangler/configuration/#generated-wrangler-configuration

Remarks

• cloudflare.noWranglerDeployConfig: true can be used to opt-out from generating deploy-config in .wrangler/deploy/config.json
• User config wrangler.toml|json is read and always merged with the highest precedence
• Modules and frameworks can extend config by extending cloudflare.wrangler object
• Nitro preset adds defaults
  • compatibility_date defaults to compatibilityDate from framework config
  • compatibility_flags defaults to ["nodejs_compat", "no_nodejs_compat_v2"]

Pages

pnpm nitro build playground --preset cloudflare_pages

dist/_worker.js/wrangler.json:

{
  "compatibility_date": "2024-09-19",
  "pages_build_output_dir": ".."
}

Modules

pnpm nitro build playground --preset cloudflare_module

.output/server/wrangler.json:

{
  "compatibility_date": "2024-09-19",
  "main": "index.mjs",
  "assets": {
    "binding": "ASSETS",
    "directory": "../public"
  }
}

[petebacondarwin]

Given this is using the cloudflare_pages plugin, this should not have an assets section in the user's wrangler.toml.
Nor should it have Durable Objects defined, since these are not valid in Pages projects.

This is likely to break the Pages CI.

Not a problem in real life because the user wouldn't have that. But in terms of testing, I will remove that from the wrangler.toml

[petebacondarwin]

For Pages projects that have a wrangler.toml it is required to have a pages_build_output_dir field in order that the config is considered for deployment. Otherwise it is completely ignored.

Depending on what you want the DX, you could either require the user to add that field themselves, or you could add it as part of the generation of wrangler.json. I think the latter is better, since I believe you want to generate a wrangler.json even if there is no user wrangler.toml.