Part 2: Start Sandboxes from It

Bind sandboxes and volumes in a Worker

src/Api.ts

import * as Cloudflare from "@alchemy.run/cloudflare";
import * as Modal from "@alchemy.run/modal";
import * as Effect from "effect/Effect";
import * as Layer from "effect/Layer";
import { MyEnv, Warm } from "./Sandbox.ts";

export default class Api extends Cloudflare.Worker<Api>()(
  "Api",
  { main: import.meta.url, compatibility: { flags: ["nodejs_compat"] } },
  Effect.gen(function* () {
    const sandboxes = yield* Modal.CreateSandbox(Warm);
    const volumes = yield* Modal.CreateVolume(MyEnv);
    return {};
  }).pipe(Effect.provide(Layer.mergeAll(Modal.CreateSandboxHttp, Modal.CreateVolumeHttp))),
) {}

CreateSandbox(Warm) boots every sandbox from the warm image. CreateVolume(MyEnv) creates volumes by name in the environment.

Run a command in a fresh sandbox

src/Api.ts

    const volumes = yield* Modal.CreateVolume(MyEnv);

    const run = Effect.fn("run")(function* (user: string, command: string) {
      const home = yield* volumes.getOrCreate(`home-${user}`);
      const sandbox = yield* sandboxes.create({
        command: ["sh", "-c", `cd /work && { ${command}; } > /home/user/.output 2>&1`],
        mounts: [{ volume: home, path: "/home/user" }],
        timeout: "5 minutes",
      });
      const { exitCode } = yield* sandbox.wait("50 seconds");
      return { exitCode, output: yield* home.readFileString("/.output") };
    });

The repository is already there: the sandbox boots from the image, so nothing clones at request time. The sandbox runs the command as its program and stops when it exits. A Worker can’t stream a sandbox’s output yet, so the command writes it to the user’s volume, mounted at /home/user, and the Worker reads it back.

Serve it

src/Api.ts

    return {};
    return {
      fetch: Effect.gen(function* () {
        const request = yield* HttpServerRequest;
        const url = new URL(request.url, "http://api");
        const user = /^\/users\/([a-z0-9-]+)\/run$/.exec(url.pathname)?.[1];
        if (request.method === "POST" && user !== undefined) {
          return yield* HttpServerResponse.json(yield* run(user, yield* request.text));
        }
        return HttpServerResponse.text("not found", { status: 404 });
      }).pipe(Effect.orDie),
    };

Deploy it

alchemy.run.ts

  Effect.gen(function* () {
    const warm = yield* Warm;
    return { image: warm.imageId };
    const api = yield* Api;
    return { url: api.url.as<string>(), image: warm.imageId };
  }),

pnpm

pnpm alchemy deploy
curl -X POST "$URL/users/ada/run" -d 'git log -1 --format=%s'

bun

bun alchemy deploy
curl -X POST "$URL/users/ada/run" -d 'git log -1 --format=%s'

npm

npx alchemy deploy
curl -X POST "$URL/users/ada/run" -d 'git log -1 --format=%s'

yarn

yarn alchemy deploy
curl -X POST "$URL/users/ada/run" -d 'git log -1 --format=%s'

The images are unchanged, so this deploy only adds the Worker.

Next

Part 3 gives each user files of their own.