This Year in Embedded Rust

This year the Embedded WG set out to build the solid foundation that the embedded Rust ecosystem requires to thrive. As we approach the date of the 2018 edition release we reflect on our progress and share our achievements with you in this post.

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Embedded Rust on stable

Stability -- AKA "my crate should not break when moving to a newer toolchain" -- was the single most requested feature by the embedded community during the 2018 roadmap planning phase.

Embedded development has been tied to the nightly channel since its very beginning, and the people that have been doing embedded development for a while have endured many breaking changes. Thankfully, those days are over: Rust 1.30 marks the first stable release where you can build fully working embedded programs without relying on unstable features.

Furthermore, we now have some unit tests that check embedded code in the compiler test suite so unintentional breakage will be caught before it makes its way into the nightly channel.

A smooth starting point

"How do I get started with embedded Rust?" has been a common question on IRC for a long time. It has not been an easy question to answer, though: maintaining documentation that relies on unstable features for a long period of time has been an uphill battle so newcomers have often run into outdated docs.

But now that stable embedded Rust is here we have put together an authoritative resource for getting started with embedded Rust: The Embedded Rust Book. We have put a lot of effort in making the first experience as frictionless as possible with the help of templates and tooling.

The embedded Rust book is not just a getting started guide; it's also meant to be the document that teaches you how to effectively use the language to write correct embedded software. We are currently amassing all our hard earned experience into patterns and tips that we are adding to this book.

Resources for everyone

The Embedded Rust Book is aimed at people that have some experience with embedded development, but we recognize that Rust has great potential for becoming people's first choice for getting their feet wet with embedded development so we have updated and will continue to work on resources, like the Discovery book, that are aimed at that demographic.

We also recognize that the target audience for embedded Rust has different levels of expertise with embedded systems and a varied set of interests so we are also building advances resources like the embedonomicon and collecting more targeted resources, like crates, in the awesome-embedded-rust list. You can find these and other of our resources in our docs webpage.

An organized community effort

All this has been accomplished with the hard work of many volunteers, both WG members and other community members. The WG members, in particular, are committed to maintaining the core crates and documentation that the ecosystem relies on. All these resources have been taken under the umbrella of the rust-embedded organization.

WG teams

The embedded space is huge: there are several architectures used in this space, many application areas, and embedded developers work with different sets of constraints: real-time constraints, memory constraints, energy / power constraints, etc.

For this reason we have been creating and growing specialized teams within the WG by adding members with different areas of expertise. This ensures that we have different perspectives when making API design decisions in core crates and when communicating the needs of the embedded community to the other Rust teams. Having specialized teams also means that the crates developed by the org can be assigned to the people with the right technical background.

On the upcoming 2018 edition

In this last sprint towards the 2018 edition we are focusing our efforts in our documentation!

You can help us by proofreading our docs, reporting errors, giving feedback on the existing content, requesting new topics and writing about topics that have not yet been covered. Every little bit of help is greatly appreciated!

One important note: our documentation makes use of the 2018 edition which requires you to use the beta channel until 1.31 is released in early December. We suggest that you use the beta channel until then to get the best experience.

Beyond 2018

Our work doesn't stop the day Rust 1.31 comes out; the 2018 edition is just the starting line of embedded Rust. As we continue to learn how to effectively use Rust for embedded development we'll continue to refine and expand our documentation as well as the core crates we maintain and develop.

Also, at this point in time ARM Cortex-M is our most mature target architecture and the majority of crates on target this architecture, but we have laid the groundwork for supporting other targets like bare metal ARM Cortex-A, ARM Cortex-R, MSP430 and RISCV. We'll continue to work on getting these targets on parity with the ARM Cortex-M target during the next year.

Finally, we'd love to hear what you would like to see happen in the embedded space in 2019. We are collecting a "wishlist" of things the embedded community would like to see get done, fixed and / or stabilized in 2019. Need some API in core to be stabilized? Would like to get some Cargo bug / papercut fixed? Let us know and we'll look into making it happen! We'll use this data to set out an embedded Rust roadmap for 2019.

Here's to a 2019 with more embedded Rust success stories (yes, "more"; wait for the upcoming revamped rust-lang website ;-)). Happy embedded hacking!