@openworkers/adapter-astro

Astro 7 adapter for OpenWorkers.

Installation

bun add -d @openworkers/adapter-astro

Usage

// astro.config.mjs
import { defineConfig } from 'astro/config';
import openworkers from '@openworkers/adapter-astro';

export default defineConfig({
  output: 'server',
  adapter: openworkers()
});

Output

dist/
  _worker.js     # The worker: one script, no imports
  _routes.json   # Route manifest for edge routing
  assets/        # Client files and prerendered pages

The worker serves prerendered pages from the ASSETS binding and renders all other routes.

Bindings

The adapter resolves cloudflare:workers to the OpenWorkers globals, so code written for Cloudflare can read its bindings:

---
import { env } from 'cloudflare:workers';

const value = await env.KV.get('key');
---

Astro.locals.runtime holds env and ctx for each request. astro:env reads its variables from env.

Astro.locals.invoke

A worker that runs in openworkers-embed has an EMBED binding. Astro.locals.invoke(command, args) calls the Rust function the host registered under that name, and returns its JSON result:

---
const user = await Astro.locals.invoke('get_user', { id: 42 });
---
<p>{user.name}</p>

In an endpoint or an action, call context.locals.invoke. Extend the type of the adapter in src/env.d.ts:

import type { Locals as OpenWorkersLocals } from '@openworkers/adapter-astro';

declare global {
  namespace App {
    interface Locals extends OpenWorkersLocals {}
  }
}

export {};

A worker without an EMBED binding gets an error when it calls Astro.locals.invoke.

Limits

• The Sharp image service is a native module. When the project uses it, the adapter selects the passthrough image service, and /_image serves the original file.
• The runtime has no Node modules. The build shows a warning when the worker imports one.
• astro dev and astro preview run on Node, not on OpenWorkers.

Deployment

# Create the worker and bind a storage bucket as ASSETS
ow workers create my-app
ow storage create my-storage
ow env create my-app-env
ow env bind my-app-env ASSETS my-storage --type assets
ow workers link my-app my-app-env

# Build and upload
bun run build
ow workers upload my-app ./dist