t3-code-android-nightly/.repos/alchemy-effect/examples/cloudflare-microvm-shell

cloudflare-microvm-shell

A browser terminal that executes shell commands on an AWS Lambda MicroVM, wired Cloudflare Worker → Durable Object → MicroVM, with command output streamed back to the browser as it is produced.

browser terminal ──ws──▶ Worker ──▶ Durable Object ──https /exec──▶ MicroVM
     (SPA)                (routes)     (session state)   (streams)   (runs sh)

• Worker (src/worker.ts) serves the terminal SPA, binds the MicroVM control plane (RunMicrovm / GetMicrovm / CreateAuthToken), and on each WebSocket upgrade provisions the session's VM and hands its endpoint + auth token to the Durable Object.
• Durable Object (src/shell-session.ts) owns one terminal session: it keeps the VM coordinates in storage (so the VM is reused across commands, not re-booted), POSTs each command to the VM's streaming /exec route, and forwards stdout/stderr to the browser chunk-by-chunk.
• MicroVM (src/shell-image.ts) is an effectful image: the module is both the image declaration and the in-VM server. The bundled Effect program spawns sh -c <command> (scoped ChildProcessSpawner) and streams its interleaved stdout/stderr, ending with an __EXIT__:<code> trailer.

Run it in dev

bun alchemy dev

Open the printed http://localhost:… URL, type a command (echo hello, uname -a, ls -la /) and press enter. Under alchemy dev the Worker and Durable Object run in local workerd while the MicroVM runs on the Floci emulator — the cross-cloud STS assume-role and the VM's TLS data plane are wired automatically (the emulator CA is trusted via NODE_EXTRA_CA_CERTS).

To exit the first-apply smoke check without keeping the session alive:

ALCHEMY_DEV_ONCE=1 bun alchemy dev

Deploy it live

bun alchemy deploy

A live deploy requires the AWS Lambda MicroVM preview entitlement on the account (the control-plane APIs are gated). Everything else — the Worker, the Durable Object, the cross-cloud IAM User + assume-role Role — is standard.