Dashboard

A graphical dashboard for the engine — containers, images, volumes, networks and a wctr terminal — built with go-widgets, running in the browser on the same engine and API as wctr. Every action shows the wctr command it stands for. This is dashboard v0.8.0.

What it does

• The Start, Stop and Restart buttons use the engine’s /start, /stop and /restart, and show the matching wctr start|stop|restart NAME line in the footer and in the terminal. Stop returns once the container has exited.
• The status bar shows the storage, from GET /system/df (for example IndexedDB 2MB of 1GB (persistent)).
• It follows GET /events instead of polling. When the stream drops, it refreshes and reconnects from the last event.
• The Volumes view shows each volume’s size and use count, and can create, inspect, remove (with force) and prune; each action shows its wctr volume … line.
• A container’s detail shows its mounts and a Stats tab: a memory gauge against the limit, a sparkline of recent readings, bytes written, log size and pids. CPU is shown as -- because it is not measured.
• The run dialog accepts -v NAME:/path[:ro].
• Networks view and Join class (v0.5.0): the networks, the networks of each container, and a Join class… dialog for a teacher’s relay.
• Surfaces view (v0.6.0): one pane per GPU surface a container opens (wasi-gfx:surface, rendered by the gpu module in the engine’s worker), titled with the container and the surface number, with its size and frame rate. A closed surface keeps its last frame, greyed, until you dismiss it.
• Surface input (v0.8.0): a pane forwards pointer events (down, up, move, in surface pixels, scaled from the letterboxed frame; events outside the frame are dropped) and key events (the KeyboardEvent.code, the text when it is one character, the modifiers) to the guest, through gpu v0.6.0’s webgpu.SurfaceInput. A press on a pane’s frame gives it the focus (drawn in the accent colour); only the focused pane sends keys, and it takes every key except F6, which leaves it. Pointer moves are coalesced to one per surface per frame. A closed surface takes no input. The playground uses dashboard v0.8.0 since playground v0.6.0.
• Open shell (v0.7.0): an “Open shell” toolbar action and a Shell tab in a container’s detail, the equivalent of wctr exec -it CONTAINER sh. It starts a TTY exec of /bin/sh at the terminal’s size, sends the keys as raw bytes, follows resizes, and shows the exit code when the shell ends. Request bodies of unknown length are streamed over the bridge, which carries the shell’s stdin. The container’s image needs a /bin/sh.
• It was tested live in Chromium and Firefox.

Live demo: https://go-wasmcontainers.github.io/dashboard/. Source: go-wasmcontainers/dashboard.

The terminal widget

The terminal in the dashboard is the Terminal widget that go-widgets/toolkit v0.342.0 adds: a subset of xterm, safe for untrusted output. It has no reply channel (nothing the output prints is ever sent back), and OSC, DCS and APC sequences are dropped.

Limitations

• The standalone demo keeps its state in memory: nothing persists across a reload. In the playground the dashboard runs on the persistent engine worker instead.
• Browsers keep Ctrl-W, Ctrl-T and Ctrl-N, so the terminal cannot use them.
• dashboard.wasm was 20.45 MB raw and 5.32 MB gzipped when measured. Dashboard v0.4.2 made it smaller (go-widgets toolkit v0.345.1), and no newer figure has been measured.

In the playground

The dashboard is the playground’s default UI since playground v0.3.0 (Containers, Images, Volumes, Networks, Terminal). The terminal-only page stays at ?ui=terminal.