nordisk/nornir

nornir-viz → wasm website — design

Class: design · Function axis: f0 the wasm slice (why a separate crate) · f1 the six wasm-capable facets (vs native-only) · f2 the eframe glow/WebGL app + headless contract · f3 the serve axum host. Strict: only what is built. Sibling: build-design.md (the 🔨 Build tab, which is native-only — see f1). Source crate: nornir-viz-web.

f0 — the wasm slice (crates/nornir-viz-web)

Rickard's ask — "prepare a wasm for nornir viz … website with nornir … nornir viz → server nornir" — is answered by a viz-only crate, not by cross-compiling the whole nornir binary. The nornir crate is a native kitchen sink (redb warehouse, tonic gRPC, tokio, gix, candle/ort, rmcp) that cannot reach wasm32-unknown-unknown. The genuinely portable content of the viz is its facett Facets — pure egui components with CPU painters and no I/O — so nornir-viz-web depends on exactly those and builds them for the browser (lib.rs:1 module doc). The native viz (nornir viz → nornir-ui) is untouched and stays fully working.

f1 — the six wasm-capable facets (and what stays native-only)

WASM_CAPABLE (crates/nornir-viz-web/src/lib.rs:47) is the discoverable legend — the six components nornir's native viz embeds that cross to the browser, each a pure egui + CPU painter with no I/O:

Native-only (the honest gate — NOT in this deck) because each needs a device / filesystem / threads the browser lacks: the 🔨 Build tab (spawns a real cargo build on a worker thread), the warehouse (redb), the gRPC / remote panes (tonic), file dialogs, and the wgpu GPU fast-paths (in wasm the CPU painters draw instead). This split is spelled out verbatim in the crate's module doc (lib.rs:21) so "what crosses" is documented, not guessed.

The deck is seeded with realistic demo data by nornir_viz_deck() -> FacetDeck (lib.rs:58) — no window, no I/O, so the headless self-check can construct it.

f2 — the eframe app + headless contract

NornirVizApp (lib.rs:124) is the eframe app: a facett_core::FacetDeck of the wasm-capable Facets that draws its own tab bar + the active facet. It runs through eframe on glow / WebGL (Cargo.toml wasm target: eframe with default-features = false, features = ["glow"] + wasm-bindgen + console_error_panic_hook) — no winit-native platform backend, no wgpu.

The same headless state_json contract the native viz exposes is exposed here: NornirVizApp::state_json (lib.rs:145) composes every facet's state_json plus the wasm_capable id list, and on wasm main.rs installs it as the window.__nornir_viz_state() JS hook so a browser drive can read what actually rendered.

f3 — the serve host ("nornir viz → server nornir")

nornir-viz-web the binary (crates/nornir-viz-web/src/main.rs) has two faces:

• native, no args — open the viz in a native eframe window (dev loop).
• nornir-viz-web serve --dir <dist> [--addr 127.0.0.1:8080] — the "server nornir" path: an axum static host (main.rs mod serve, run at main.rs:66, feature serve) that serves the built wasm bundle as a website via tower-http ServeDir, with an index.html fallback so any route re-serves the SPA (main.rs:98), until Ctrl-C.

The serve feature is off by default (Cargo.toml [features]) so a plain cargo build and the wasm build pull no server stack. The wasm bundle itself is produced by ./build-wasm.sh (wasm-bindgen) into dist/, then handed to serve.