Scaling Rust Adoption Through Training

Android 14 is the third main Android launch with Rust assist. We are already seeing a number of advantages:

These constructive early outcomes offered an attractive motivation to extend the velocity and scope of Rust adoption. We hoped to perform this by investing closely in coaching to broaden from the early adopters.

Early adopters are sometimes prepared to simply accept extra threat to check out a brand new know-how. They know there shall be some inconveniences and a steep studying curve however are prepared to study, typically on their very own time.

Scaling up Rust adoption required transferring past early adopters. For that we have to guarantee a baseline stage of consolation and productiveness inside a set time frame. An essential a part of our technique for undertaking this was coaching. Unfortunately, the kind of coaching we needed to supply merely didn’t exist. We made the choice to put in writing and implement our personal Rust coaching.

Our objectives for the coaching have been to:

• Quickly ramp up engineers: It is difficult to take folks away from their common work for a protracted time frame, so we aimed to supply a strong basis for utilizing Rust in days, not weeks. We couldn’t make anyone a Rust skilled in so little time, however we might give folks the instruments and basis wanted to be productive whereas they continued to develop. The objective is to allow folks to make use of Rust to be productive members of their groups. The time constraints meant we couldn’t train folks programming from scratch; we additionally determined to not train macros or unsafe Rust intimately.
• Make it participating (and enjoyable!): We needed folks to see a variety of Rust whereas additionally getting hands-on expertise. Given the scope and time constraints talked about above, the coaching was essentially information-dense. This known as for an interactive setting the place folks might rapidly ask inquiries to the teacher. Research exhibits that retention improves when folks can rapidly confirm assumptions and apply new ideas.
• Make it related for Android: The Android-specific tooling for Rust was already documented, however we needed to indicate engineers learn how to use it through labored examples. We additionally needed to doc rising requirements, similar to utilizing thiserror and anyhow crates for error dealing with. Finally, as a result of Rust is a brand new language within the Android Platform (AOSP), we would have liked to indicate learn how to interoperate with present languages similar to Java and C++.

With these three objectives as a place to begin, we regarded on the present materials and accessible instruments.

Existing Material

Documentation is a key worth of the Rust neighborhood and there are various nice assets accessible for studying Rust. First, there may be the freely accessible Rust Book, which covers nearly all the language. Second, the usual library is extensively documented.

Because we knew our audience, we might reinforce assumptions than most materials discovered on-line. We created the course for engineers with at the very least 2–3 years of coding expertise in both C, C++, or Java. This allowed us to maneuver rapidly when explaining ideas acquainted to our viewers, similar to “management move”, “stack vs heap”, and “methods”. People with different backgrounds can study Rust from the various different assets freely accessible on-line.

Technology

For free-form documentation, mdBook has turn out to be the de facto customary within the Rust neighborhood. It is used for official documentation such because the Rust Book and Rust Reference.

A very fascinating characteristic is the flexibility to embed executable snippets of Rust code. This is essential to creating the coaching participating for the reason that code could be edited reside and executed straight within the slides:

In addition to being a well-recognized neighborhood customary, mdBook affords the next essential options:

• Maintainability: mdbook check compiles and executes each code snippet within the course. This allowed us to evolve the category over time whereas guaranteeing that we at all times confirmed legitimate code to the contributors.
• Extensibility: mdBook has a plugin system which allowed us to increase the device as wanted. We relied on this characteristic for translations and ASCII artwork diagrams.

These options made it straightforward for us to decide on mdBook. While mdBook is just not designed for shows, the output regarded OK on a projector once we restricted the vertical dimension of every web page.

Supporting Translations

Android has builders and OEM companions in lots of nations. It is crucial that they will adapt present Rust code in AOSP to suit their wants. To assist translations, we developed mdbook-i18n-helpers. Support for multilingual documentation has been a neighborhood want since 2015 and we’re glad to see the plugins being adopted by a number of different initiatives to provide maintainable multilingual documentation for everyone.

With the know-how and format nailed down, we began writing the course. We roughly adopted the define from the Rust Book because it coated most of what we have to cowl. This gave us a 3 day course which we known as Rust Fundamentals. We designed it to run for 3 days for 5 hours a day and embody Rust syntax, semantics, and essential ideas similar to traits, generics, and error dealing with.

We then prolonged Rust Fundamentals with three deep dives:

• Rust in Android: a half-day course on utilizing Rust for AOSP growth. It contains interoperability with C, C++, and Java.
• Bare-metal Rust: a full-day class on utilizing Rust for bare-metal growth. Android gadgets ship vital quantities of firmware. These elements are sometimes foundational in nature (for instance, the bootloader, which establishes the belief for the remainder of the system), thus they should be safe.
• Concurrency in Rust: a full-day class on concurrency in Rust. We cowl each multithreading with blocking synchronization primitives (similar to mutexes) and async/await concurrency (cooperative multitasking utilizing futures).

A big set of in-house and neighborhood translators have helped translate the course into a number of languages. The full translations have been Brazilian Portuguese and Korean. We are engaged on Simplified Chinese and Traditional Chinese translations as properly.

Course Reception

We began instructing the category in late 2022. In 2023, we employed a vendor, Immunant, to show nearly all of courses for Android engineers. This was essential for scalability and for high quality: devoted instructors quickly found the place the course contributors struggled and will adapt the supply. In addition, over 30 Googlers have taught the course worldwide.

More than 500 Google engineers have taken the category. Feedback has been very constructive: 96% of contributors agreed it was value their time. People constantly informed us that they beloved the interactive type, highlighting the way it helped to have the ability to ask clarifying questions at any time. Instructors famous that individuals gave the course their undivided consideration as soon as they realized it was reside. Live-coding calls for loads from the teacher, however it’s value it as a result of excessive engagement it achieves.

Most importantly, folks exited this course and have been capable of be instantly productive with Rust of their day jobs. When contributors have been requested three months later, they confirmed that they have been capable of write and assessment Rust code. This matched the outcomes from the a lot bigger survey we made in 2022.

We have been instructing Rust courses at Google for a yr now. There are some things that we need to enhance: higher subject ordering, extra workouts, and extra speaker notes. We would additionally like to increase the course with extra deep dives. Pull requests are very welcome!

The full course is accessible at no cost at https://google.github.io/comprehensive-rust/. We are thrilled to see folks beginning to use Comprehensive Rust for courses around the globe. We hope it may be a helpful useful resource for the Rust neighborhood and that it’ll assist each small and enormous groups get began on their Rust journey!

We are grateful to the 190+ contributors from everywhere in the world who created greater than 1,000 pull requests and points on GitHub. Their bug stories, fixes, and suggestions improved the course in numerous methods. This contains the 50+ individuals who labored laborious on writing and sustaining the various translations.

Special because of Andrew Walbran for writing Bare-metal Rust and to Razieh Behjati, Dustin Mitchell, and Alexandre Senges for writing Concurrency in Rust.

We additionally owe a substantial amount of because of the various volunteer instructors at Google who’ve been spending their time instructing courses across the globe. Your suggestions has helped form the course.

Finally, because of Jeffrey Vander Stoep, Ivan Lozano, Matthew Maurer, Dmytro Hrybenko, and Lars Bergstrom for offering suggestions on this put up.