Changelog

[0.1.0] - 2026-09-12

Version policy note: the ecosystem stays early — everything is 0.1.0. This entry records the runtime widget work that joined the repo on top of the existing xtop-plugin-samurai crate.

Runtime widget hosts (opt-in)

• New crate xtop-plugin-wasm (xtop-plugin-wasm, feature plugin-wasm in the kernel): loads sandboxed *.wasm widgets in-process with wasmi. Discovery in <config dir>/wasm/ (override XTOP_WASM_DIR), mtime hot reload, status/render/reload debug actions, and an examples/inspect.rs harness that runs a module without the kernel. Sandbox limits: 100M fuel per host→guest call sequence, 64 MiB linear memory, only the host.log import linked.
• New crate xtop-plugin-external (xtop-plugin-external, feature plugin-external): one helper process per widget over line-delimited JSON. Descriptors in <config dir>/external/*.json (override XTOP_EXTERNAL_DIR), per-response timeout, last-good draw list on failures, clean shutdown. Any language with a runtime can implement a widget.
• New shared crates:
  • xtop-wasm-contract — serializable Manifest/State/DrawList contract plus the external Request/Response protocol (ABI "1").
  • xtop-widget-replay — host-side replay of draw lists onto a ratatui frame and the plugin-context → contract State conversion.
  • xtop-wasm-guest — Rust guest SDK (export_widget! macro, ABI exports, host.log usage) for building widgets to wasm32-unknown-unknown.
• Kernel integration is additive and opt-in: the two hosts are non-default features, register through the existing plugin widget path (precedence over compiled-in packs), and leave the compiled-in plugin/pack system untouched. See docs/decisions.md (ADR-001).

Examples

• examples/wasm/ — Rust guests clock, cpu, procs and load-stats (statistics: EMA, z-score), plus freestanding C guests c-ticker and c-cpu-avg built with clang + wasm-ld and no libc/WASI.
• examples/external/ — Lua (lua-clock, lua-histogram), Python (python-cpu, python-cpu-chart, python-mem-regression) and Node (node-clock) helper widgets, all dependency-free.

Tooling

• scripts/build-examples.sh — builds every guest (Rust wasm32 + C) and can smoke-test them through the real host loader.
• scripts/test-wasm-e2e.sh, scripts/test-external-e2e.sh — end-to-end checks of both lanes (skip runtimes that are not installed).
• scripts/ci.sh — new optional stages wasm and external; the default stages (fmt, clippy, check, test) are unchanged.

Documentation

• docs/wasm-widgets.md — WASM host: ABI, sandbox limits, draw-list ops, hot reload, authoring guide.
• docs/external-widgets.md — external host: descriptors, protocol, lifecycle, timeouts.
• docs/decisions.md — ADR-001 (runtime widget hosts).
• examples/wasm/README.md, examples/external/README.md — per-example build/run instructions.

Compatibility

• No breaking changes to xtop-plugin-samurai or to the xtop-plugin-api contract. The new crates are additive workspace members.
• The guest-facing ABI is versioned ("1"); guests declaring a different api value load with a warning.