dckcandClaude Opus 5.5
88739d9495
Each vat is a Durable Object that stores code by hash and runs it as a facet through the Worker Loader: an empty env, no fetch, storage that carries over upgrades. Two sockets with no configured address: whoever starts workerd hands them in (systemd socket activation), so the admin socket is the authority to install code. Tests run a real workerd: install, upgrade, isolation between vats, no fetch, the public port can't install, and code and state survive a crash. They spawn the package binary rather than the .bin shim, which forks workerd, so killing the shim orphaned it and the test run never ended. Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
73 lines
2.5 KiB
JavaScript
73 lines
2.5 KiB
JavaScript
/** @file toybox supervisor: one Vat per name; its app runs as a facet on installed code. */
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import { DurableObject, WorkerEntrypoint } from "cloudflare:workers";
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const hex = (buf) => [...new Uint8Array(buf)].map((b) => b.toString(16).padStart(2, "0")).join("");
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/**
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* Holds the vat's installed code; the app facet holds the app's state.
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*
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* Code is stored by hash so the facet can be rebuilt after hibernation or a
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* restart. The app gets an empty `env` and no `fetch`.
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*/
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export class Vat extends DurableObject {
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constructor(ctx, env) {
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super(ctx, env);
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ctx.storage.sql.exec("CREATE TABLE IF NOT EXISTS bundle (hash TEXT PRIMARY KEY, src TEXT)");
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ctx.storage.sql.exec("CREATE TABLE IF NOT EXISTS current (k INTEGER PRIMARY KEY CHECK (k = 0), hash TEXT)");
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}
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/**
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* Install `src` and run the app on it; the app's storage carries over.
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*
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* @param {string} src an ES module exporting `class App extends DurableObject`
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* @returns {Promise<string>} the code's SHA-256, hex
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*/
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async start(src) {
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const hash = hex(await crypto.subtle.digest("SHA-256", new TextEncoder().encode(src)));
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this.ctx.storage.sql.exec("INSERT OR IGNORE INTO bundle VALUES (?, ?)", hash, src);
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this.ctx.storage.sql.exec("INSERT OR REPLACE INTO current VALUES (0, ?)", hash);
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this.ctx.facets.abort("app", new Error("upgraded"));
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return hash;
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}
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#app(hash, src) {
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return this.ctx.facets.get("app", () => {
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const worker = this.env.LOADER.get(hash, () => ({
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compatibilityDate: "2026-10-01",
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mainModule: "app.js",
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modules: { "app.js": src },
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env: {},
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globalOutbound: null,
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}));
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return { class: worker.getDurableObjectClass("App") };
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});
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}
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fetch(request) {
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const [row] = this.ctx.storage.sql
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.exec("SELECT b.hash, b.src FROM current c JOIN bundle b USING (hash)")
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.toArray();
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if (!row) return new Response("no code installed\n", { status: 404 });
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return this.#app(row.hash, row.src).fetch(request);
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}
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}
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const vatOf = (env, url) => env.VATS.getByName(new URL(url).pathname.split("/")[1]);
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/** The http socket: `/<vat>/...` goes to that vat's app. */
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export class Public extends WorkerEntrypoint {
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fetch(request) {
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return vatOf(this.env, request.url).fetch(request);
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}
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}
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/** The admin socket: `PUT /<vat>` with an ES module body installs and starts it. */
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export class Admin extends WorkerEntrypoint {
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async fetch(request) {
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if (request.method !== "PUT") return new Response("PUT code to /<vat>\n", { status: 405 });
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return new Response((await vatOf(this.env, request.url).start(await request.text())) + "\n");
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}
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}
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export default Public;
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