WireWeaver

WireWeaver is a collection of crates for designing #[no_std] APIs:

• RPC, streams and properties
• API traits (composable building blocks)
• Backwards and forwards compatibility
• Server and client code generation, blocking and async
  • Currently for Rust and Python
• Cross platform USB, Ethernet and CAN Bus support
• Introspection and dynamic Python clients
• CLI and GUI tooling
• Uses shrink_wrap wire format
  • Zero-copy, no-alloc and no_std
  • Dynamically sized user-defined types and vectors (on no_std as well)
  • Bit level packing and more

Current state is - approaching alpha release. See FEATURES.md for what works today, what is in progress and what is planned. CHANGELOG.md tells the project's history, from its 2017 YAML beginnings to the latest release; each crate's own CHANGELOG.md has the details.

TLDR

Documentation with a step-by-step guide is available here.

Traits can be made "global" by publishing them on crates.io. Useful for things like logging, GPIO control or firmware update, allowing code reuse across projects.

Wire format used (called ShrinkWrap) is binary and designed to use bits and nibbles to make it compact without compression. See comparison to other formats in examples/compare_wire_formats.

Standard library

Common data types and traits are located in the ww_stdlib repository. Notable ones are:

• ww_date_time - ISO 8601 date and time with optional time zone and nanoseconds, as small as 32 bits. Also NaiveDate and NaiveTime.
• ww_version - SemVer version (including pre and build strings).
• ww_numeric - Various numeric types, including offset-scale and subtypes.
• ww_si - SI units and derived values.
• ww_gpio - GPIO control data types and remote bridging API.
• ww_can_bus - CAN bus API: configure, send and receive frames, error state, optional filters and buffers.
• ww_dfu - Firmware update API, see the guide to its eight update scenarios.
• ww_log - The device's log: defmt frames (decoded with the ELF) or text records, as reliable streams.
• ww_self - Dynamic access to APIs (API model AST in ShrinkWrap format).

Quick start

Easiest way to start using WireWeaver is through one of the templates below, which contain firmware for several development boards, API, client and Python bindings crates.

If you do not have physical hardware at hand, there is virtual device support.

Microcontroller API over USB template

WireWeaver template

This is a minimal example showing an MCU firmware with USB, common no_std API crate, server on the MCU and client in Rust and Python.

Microcontroller API over Ethernet template

TODO

Setup from scratch

See Project setup page in the docs, which explains how setup projects in more detail for both std and no_std use.

Low level wire format use

TODO

Wire format

WireWeaver uses wire format called ShrinkWrap - compact zero-copy wire format for microcontrollers using no allocator and supporting dynamic types. If you only want to serialize and deserialize some data types, it can be used stand-alone.

Crate naming

wire_weaver_ prefix is used on core crates that implement all the functionality.
ww_ prefix is used on crates using WireWeaver to provide standard library types and traits. Use it as well if you think that your crate is useful across multiple projects. Standard library is in ww_stdlib repository, contributions are welcome!