Files
spoon/docs/agent-terminal.md
T

119 lines
7.2 KiB
Markdown

# Interactive terminal
A real shell inside the user's persistent box (`spoon-box-{username}`). There are
two entry points, both bridging to the **same** box:
- The workspace **Terminal** tab — a shell opened at the thread's checkout
(`~/Code/{spoon}/{branch}`).
- The **My Machine** page (`/machine`) — a `~`-rooted shell into the same box.
Both are an xterm.js front end bridged to a bash/tmux PTY via `docker exec` into
the box. There is no per-job `spoon-agent-term-*` container anymore — the box is
long-running and shared by the agent, the editor, and both terminals.
## Architecture
```
browser (xterm.js)
│ 1a. GET /api/agent-jobs/:id/terminal-token (Convex-auth'd, owner only)
│ → { url: "wss://worker…/jobs/:id/terminal?token=…", expiresAt }
│ 1b. GET /api/box/terminal-token (Convex-auth'd; username
│ → { url: "wss://worker…/box/terminal?token=…", expiresAt } derived
│ server-side)
│ 2. WebSocket wss://worker.<domain>/{jobs/:id|box}/terminal?token=…
nginx ── upgrade ──► spoon-agent-worker :3921
│ verify HMAC token (job-scoped or username-scoped)
│ docker exec -it → bash/tmux PTY
spoon-box-{username} (Fedora box; persistent home mounted)
```
- The browser **never** holds the worker secret. The Next app mints a short-lived
HMAC token; the worker verifies it. The job terminal token is minted only after
a Convex ownership check; the box terminal token carries the username derived
**server-side** from the authed user (never from the request).
- Frames: **binary** = stdin/stdout bytes; **text JSON** `{type:"resize",cols,rows}`
= resize. The token's 2-minute expiry is a _connect_ window; an established
session persists.
- The shell prefers `tmux new-session -A -s spoon` (falls back to `bash -l`), so
reconnecting reattaches the same session. The box itself is idle-reaped after
`SPOON_AGENT_BOX_IDLE_MS` (default 30m) once no job or terminal holds it.
## Configuration
| Where | Variable | Required? | Notes |
| -------- | --------------------------------------- | --------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
| Next app | `NEXT_PUBLIC_SPOON_AGENT_WORKER_WS_URL` | **Yes** | Browser-facing worker WS base, e.g. `wss://worker.spoon.gbrown.org` (prod) or `ws://localhost:3921` (dev). **Build-time** (`NEXT_PUBLIC`): for the Docker image it must be passed as a build arg (wired in `docker/Dockerfile` + `docker/compose.yml`, sourced from the build env file), not a runtime env. Unset → the Terminal tab shows "not configured". |
| Next app | `SPOON_AGENT_TERMINAL_SECRET` | No | HMAC secret for signing tokens. Falls back to `SPOON_AGENT_WORKER_INTERNAL_TOKEN`. |
| Worker | `SPOON_AGENT_TERMINAL_SECRET` | No | Must match the Next app's. Falls back to `SPOON_AGENT_WORKER_INTERNAL_TOKEN` (already shared), so by default **no new secret is needed**. |
| Worker | `SPOON_AGENT_BOX_IDLE_MS` | No | Idle-box reap delay, shared with agent jobs (default `1800000`). The terminal holds the box open while connected. |
Because the secret defaults to the already-shared worker token, the **only**
required step is setting `NEXT_PUBLIC_SPOON_AGENT_WORKER_WS_URL` and exposing the
worker over nginx (prod).
## Exposing the worker (prod, nginx)
The worker and nginx are on the same `nginx-bridge` network, so nginx can reach
`spoon-agent-worker:3921` directly — no published port needed. Add a server block
that upgrades WebSockets:
```nginx
server {
listen 443 ssl;
server_name worker.spoon.gbrown.org;
# ssl_certificate ... ; ssl_certificate_key ... ;
location / {
proxy_pass http://spoon-agent-worker:3921;
proxy_http_version 1.1;
proxy_set_header Upgrade $http_upgrade;
proxy_set_header Connection "upgrade";
proxy_set_header Host $host;
proxy_read_timeout 86400s; # keep idle terminals open
proxy_send_timeout 86400s;
}
}
```
Then set on the Next app: `NEXT_PUBLIC_SPOON_AGENT_WORKER_WS_URL=wss://worker.spoon.gbrown.org`.
> The worker's HTTP routes (`/jobs/:id/tree`, `/box/*`, etc.) require the
> internal bearer token, so exposing the worker host only usefully exposes the
> token-gated `/jobs/:id/terminal` and `/box/terminal` upgrades. Still, restrict
> the server block to TLS.
## Dev testing (no nginx)
The dev worker runs on the host at `localhost:3921` (`bun dev:next:worker`), so
the browser can hit it directly:
```
NEXT_PUBLIC_SPOON_AGENT_WORKER_WS_URL=ws://localhost:3921
```
Note: the terminal uses **dockerode** against the Docker socket. In dev with
Podman, point it at the Podman socket (run `podman system service` and set
`DOCKER_HOST=unix://$XDG_RUNTIME_DIR/podman/podman.sock`), or run the worker in
Docker mode. Prod (Docker socket mounted) works as-is.
## Security
- Owner-only: the job token route uses Convex auth + ownership assertion; the
box token derives the username server-side from the authed user.
- Tokens are short-lived (2m connect window), scoped (job-scoped or
username-scoped), and HMAC-signed.
- A shell in the box can reach the network and the repo's git credentials. This
is intended for the single-user self-hosted deployment; do not expose the
worker domain without TLS, and keep the deployment single-tenant.
## Tools in the shell
The box image ships `bash`, `tmux`, `neovim`, `git`, `ripgrep`, `jq`, `python3`,
`node`, `bun`, `pnpm`, `yarn`, `curl`/`wget`, `unzip`, plus QoL tooling (`fzf`,
`fd`, `bat`, `eza`, `zoxide`, `gh`, `gum`, `oh-my-posh`) and the agent CLIs
(`codex`, `opencode`, `claude`). Personalize the shell in **Settings → Dotfiles**
(overlay files + an optional dotfiles repo), applied to the persistent home; see
[dotfiles.md](dotfiles.md).