Support dynamic worker loading

[penalosa]

Support cloudflare/workerd#4383

---

• Tests
  • Tests included
  • Tests not necessary because:
• Public documentation
  • Cloudflare docs PR(s):
  • Documentation not necessary because: this is an experimental pre-release feature
• Wrangler V3 Backport
  • Wrangler PR:
  • Not necessary because: not available in v3

[pkg-pr-new]

create-cloudflare

npm i https://pkg.pr.new/create-cloudflare@10012

@cloudflare/kv-asset-handler

npm i https://pkg.pr.new/@cloudflare/kv-asset-handler@10012

miniflare

npm i https://pkg.pr.new/miniflare@10012

@cloudflare/pages-shared

npm i https://pkg.pr.new/@cloudflare/pages-shared@10012

@cloudflare/unenv-preset

npm i https://pkg.pr.new/@cloudflare/unenv-preset@10012

@cloudflare/vite-plugin

npm i https://pkg.pr.new/@cloudflare/vite-plugin@10012

@cloudflare/vitest-pool-workers

npm i https://pkg.pr.new/@cloudflare/vitest-pool-workers@10012

@cloudflare/workers-editor-shared

npm i https://pkg.pr.new/@cloudflare/workers-editor-shared@10012

wrangler

npm i https://pkg.pr.new/wrangler@10012

commit: 34d24b0

[changeset-bot]

🦋 Changeset detected

Latest commit: 34d24b0

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 5 packages

Name	Type
miniflare	Minor
wrangler	Minor
@cloudflare/pages-shared	Patch
@cloudflare/vite-plugin	Major
@cloudflare/vitest-pool-workers	Patch

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR

[github-actions]

Failed to automatically backport this PR's changes to Wrangler v3. Please manually create a PR targeting the v3-maintenance branch with your changes. Thank you for helping us keep Wrangler v3 supported!

Depending on your changes, running git rebase --onto v3-maintenance main penalosa/support-dynamic-worker-loading might be a good starting point.

Notes:

• your PR branch should be named v3-backport-10012
• add the skip-v3-pr label to the current PR to stop this workflow from failing

[danlapid]

Maybe @kentonv will have some comments

[petebacondarwin]

Surely minors?

[petebacondarwin]

What does id mean in this binding.
I guess my question is, "What does it mean to have multiple Worker Loaders?"

[kentonv]

Miniflare should randomly-generate this ID instead. It turns out the edge runtime doesn't support multiple bindings to the same worker loader namespace so there's not much reason to expose this.

[kentonv]

Oh wait, no need to randomly generate. It can just be left null (not empty string, but null/omitted), in which case workerd will do the right thing.

[petebacondarwin]

Will it be needed for production deployments? In other words can we just remove it from wrangler.jsonc altogether? Or just ignore it in local dev?

[kentonv]

Production does not support this option at all, that's why I recommend removing it.

[petebacondarwin]

Not accessible from getPlatformProxy()?

[petebacondarwin]

Approved as this is good as it stands but I do think it would be nice to support getPlatformProxy() if it doesn't already.

[kentonv]

I'd love to see this merged and released soon as I need it for a project. :)

[threepointone]

Let's talk about this before landing it? Just want to make sure we agree on the api and how we're going to roll it out. @kentonv you can use this locally immediately with the prerelease builds npm i https://pkg.pr.new/wrangler@10012

[threepointone]

soft blocking just so we can chat about this

[penalosa]

@threepointone this isn't a stable release—it's going out as an unsafe binding. We can (and probably will) change the API/binding config before graduating to a stable binding

[kentonv]

Not sure if this is a problem in this PR or pre-existing, but I noticed that when I run wrangler dev, this binding is displayed wrong:

Your Worker has access to the following bindings:
Binding                                                      Resource             Mode
env.worker-loader (LOADER)                                   Unsafe Metadata      not supported

The binding name and type are swapped in the display -- it should say:

env.LOADER (worker-loader)                                   Unsafe Metadata      not supported

(The binding seems to work, though. This is just a display problem.)