Part 3: A Copy per User

Start a user’s sandbox from Golden

src/Api.ts

    const userSandbox = Effect.fn("userSandbox")(function* (user: string) {
      const [existing] = yield* sandboxes.list({ labels: { user } });
      if (existing === undefined) {
        return yield* sandboxes.create({ noEnv: true, autoStop: "10 minutes", labels: { user } });
      }
      const sandbox = yield* sandboxes.connect(existing.id);
      yield* sandbox.resume({ autoStop: "10 minutes" });
      return sandbox;
    });

A user’s first request starts their sandbox from Golden, with the repository already cloned. The label finds it again on their next request.

Their changes stay in their copy

src/Api.ts

        if (request.method === "POST" && url.pathname === "/run") {
          const result = yield* run(yield* request.text).pipe(Effect.scoped);
          return yield* HttpServerResponse.json(result);
        }
        const match = /^\/users\/([a-z0-9-]+)\/files\/(.+)$/.exec(url.pathname);
        if (match !== null) {
          const sandbox = yield* userSandbox(match[1]!);
          if (request.method === "PUT") yield* sandbox.files.write(`repo/${match[2]}`, yield* request.text);
          return yield* HttpServerResponse.json({ content: yield* sandbox.files.readText(`repo/${match[2]}`) });
        }

Each user edits their own copy of the repository. Golden never changes, so the next sandbox started from it doesn’t see their edits.

Resume where they left off

The sandbox stops after ten idle minutes and Boat saves its disk. resume on their next request brings it back with their files, for up to 14 days.

pnpm

pnpm alchemy deploy
curl -X PUT "$URL/users/ana/files/notes.md" -d 'hello'
curl "$URL/users/ana/files/notes.md"

bun

bun alchemy deploy
curl -X PUT "$URL/users/ana/files/notes.md" -d 'hello'
curl "$URL/users/ana/files/notes.md"

npm

npx alchemy deploy
curl -X PUT "$URL/users/ana/files/notes.md" -d 'hello'
curl "$URL/users/ana/files/notes.md"

yarn

yarn alchemy deploy
curl -X PUT "$URL/users/ana/files/notes.md" -d 'hello'
curl "$URL/users/ana/files/notes.md"

Next

Part 4 changes the snapshot.