¶Architecture

Elyra is a Laravel-shaped desktop framework: the same ergonomic building blocks — an application container, service providers, middleware, a typed client — but compiled to a single native binary with no runtime interpreter.

¶The Laravel map

¶Processes and threads

• The event loop + webview live on the main thread (required on macOS).
• A separate multi-thread tokio runtime owns all IPC work.
• The custom-protocol handler is asynchronous: each request is spawned onto tokio and responded to from there, so the UI thread never blocks on a command or an event long-poll.

┌─────────────── main thread ───────────────┐     ┌──── tokio runtime ────┐
│ tao event loop  ──  wry webview (WebKit)   │     │  command dispatch     │
│   └ elyra:// custom protocol handler ──────┼────▶│  middleware pipeline  │
│                                            │◀────┼─  EventBus flushes     │
└────────────────────────────────────────────┘     └───────────────────────┘

¶Request lifecycle (a command)

1. Frontend calls invoke("name", ...args) (or api.name(...)).
2. @elyra/runtime MessagePack-encodes the args and fetches elyra://localhost/__cmd/name.
3. The protocol handler spawns the request on tokio.
4. CommandRegistry::dispatch runs the middleware pipeline, then the command.
5. #[command] decodes the arg tuple, runs your async fn, and MessagePack-encodes the result (or maps a Result::Err to an error response).
6. The bytes are returned; the runtime decodes them into the resolved value.

See wire format for the exact bytes.

¶State ownership

Rust owns the state; the frontend is a projection. Instead of one IPC round per change, the EventBus accumulates events and flushes them as a single batch to a long-poll the frontend holds open — binary, no base64.

¶Crates

framework/   elyra          App, Container/Ctx, Command, EventBus, shell (tao+wry),
                            windows, tray, updater, codegen
macros/      elyra-macros   #[command], #[derive(Model)]
database/    elyra-db       Database (sqlx Any), migrations, models — no GUI deps,
                            so the CLI can use it without linking tao/wry
ratatosk/    ratatosk       the `rata` CLI
runtime/     @elyra/runtime invoke(), channel(), the generated api.*

elyra-db is deliberately GUI-free so rata migrate (and any headless tool) can drive the database without pulling in the windowing stack.

¶Performance principles

1. Binary IPC — MessagePack over the custom protocol via fetch(). No JSON in the hot path; streaming and ArrayBuffer for free.
2. Rust owns state — diffs pushed via the EventBus, batched per flush.
3. Assets from memory — rust-embed + protocol handler, no disk I/O at start.
4. Never block the UI thread — every command runs on tokio.