Android 14 is the third main Android launch with Rust help. We’re already seeing a number of advantages:

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

Early adopters are sometimes keen to just accept extra danger to check out a brand new know-how. They know there will likely be some inconveniences and a steep studying curve however are keen to be taught, usually 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 period. An necessary a part of our technique for conducting this was coaching. Sadly, the kind of coaching we wished to offer merely didn’t exist. We made the choice to write down and implement our personal Rust coaching.

Our targets for the coaching have been to:

• Shortly ramp up engineers: It’s exhausting to take individuals away from their common work for a protracted time period, so we aimed to offer a stable basis for utilizing Rust in days, not weeks. We couldn’t make anyone a Rust knowledgeable in so little time, however we might give individuals the instruments and basis wanted to be productive whereas they continued to develop. The purpose is to allow individuals to make use of Rust to be productive members of their groups. The time constraints meant we couldn’t train individuals programming from scratch; we additionally determined to not train macros or unsafe Rust intimately.
• Make it partaking (and enjoyable!): We wished individuals 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 individuals might shortly ask inquiries to the trainer. Analysis reveals that retention improves when individuals can shortly confirm assumptions and observe new ideas.
• Make it related for Android: The Android-specific tooling for Rust was already documented, however we wished to point out engineers find out how to use it through labored examples. We additionally wished to doc rising requirements, resembling utilizing thiserror and anyhow crates for error dealing with. Lastly, as a result of Rust is a brand new language within the Android Platform (AOSP), we would have liked to point out find out how to interoperate with present languages resembling Java and C++.

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

Present Materials

Documentation is a key worth of the Rust neighborhood and there are a lot of nice sources obtainable for studying Rust. First, there’s the freely obtainable Rust Guide, which covers virtually the entire language. Second, the usual library is extensively documented.

As a result of we knew our audience, we might toughen assumptions than most materials discovered on-line. We created the course for engineers with not less than 2–3 years of coding expertise in both C, C++, or Java. This allowed us to maneuver shortly when explaining ideas acquainted to our viewers, resembling “management move”, “stack vs heap”, and “strategies”. Folks with different backgrounds can be taught Rust from the numerous different sources freely obtainable on-line.

Expertise

Without cost-form documentation, mdBook has grow to be the de facto commonplace within the Rust neighborhood. It’s used for official documentation such because the Rust Guide and Rust Reference.

A very fascinating function is the flexibility to embed executable snippets of Rust code. That is key to creating the coaching partaking because the code could be edited dwell and executed straight within the slides:

Along with being a well-known neighborhood commonplace, mdBook presents the next necessary 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 individuals.
• Extensibility: mdBook has a plugin system which allowed us to increase the software as wanted. We relied on this function for translations and ASCII artwork diagrams.

These options made it straightforward for us to decide on mdBook. Whereas mdBook isn’t designed for shows, the output regarded OK on a projector after we restricted the vertical measurement of every web page.

Supporting Translations

Android has builders and OEM companions in lots of nations. It’s crucial that they will adapt present Rust code in AOSP to suit their wants. To help translations, we developed mdbook-i18n-helpers. Help 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 Guide because it lined 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 necessary ideas resembling 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 consists of interoperability with C, C++, and Java.
• Naked-metal Rust: a full-day class on utilizing Rust for bare-metal growth. Android units ship important 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 have to be safe.
• Concurrency in Rust: a full-day class on concurrency in Rust. We cowl each multithreading with blocking synchronization primitives (resembling 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 complete translations have been Brazilian Portuguese and Korean. We’re engaged on Simplified Chinese language and Conventional Chinese language translations as properly.

Course Reception

We began instructing the category in late 2022. In 2023, we employed a vendor, Immunant, to show the vast majority of lessons for Android engineers. This was necessary for scalability and for high quality: devoted instructors quickly found the place the course individuals struggled and will adapt the supply. As well as, over 30 Googlers have taught the course worldwide.

Greater than 500 Google engineers have taken the category. Suggestions has been very constructive: 96% of individuals agreed it was value their time. Folks persistently advised us that they liked 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 dwell. Reside-coding calls for loads from the trainer, however it’s value it as a result of excessive engagement it achieves.

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

We’ve got been instructing Rust lessons at Google for a yr now. There are some things that we wish to enhance: higher matter ordering, extra workouts, and extra speaker notes. We’d additionally like to increase the course with extra deep dives. Pull requests are very welcome!

The complete course is out there totally free at https://google.github.io/comprehensive-rust/. We’re thrilled to see individuals beginning to use Complete Rust for lessons around the globe. We hope it may be a helpful useful resource for the Rust neighborhood and that it’ll assist each small and huge groups get began on their Rust journey!

We’re grateful to the 190+ contributors from everywhere in the world who created greater than 1,000 pull requests and points on GitHub. Their bug experiences, fixes, and suggestions improved the course in numerous methods. This consists of the 50+ individuals who labored exhausting on writing and sustaining the numerous translations.

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

We additionally owe an excessive amount of because of the numerous volunteer instructors at Google who’ve been spending their time instructing lessons across the globe. Your suggestions has helped form the course.

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