Android 14 is the third main Android launch with Rust help. We’re already seeing an a variety of benefits:

These constructive early outcomes offered an attractive motivation to extend the pace 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 just accept extra danger to check out a brand new know-how. They know there shall be some inconveniences and a steep studying curve however are prepared to be taught, typically on their very own time.

Scaling up Rust adoption required shifting past early adopters. For that we have to guarantee a baseline degree 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 jot down and implement our personal Rust coaching.

Our objectives for the coaching had been to:

• Rapidly ramp up engineers: It’s onerous to take individuals away from their common work for an extended time period, so we aimed to offer a strong basis for utilizing Rust in days, not weeks. We couldn’t make anyone a Rust skilled in so little time, however we may 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 loads of Rust whereas additionally getting hands-on expertise. Given the scope and time constraints talked about above, the coaching was essentially information-dense. This referred to as for an interactive setting the place individuals may rapidly ask inquiries to the teacher. Analysis exhibits that retention improves when individuals can rapidly confirm assumptions and apply new ideas.
• Make it related for Android: The Android-specific tooling for Rust was already documented, however we wished to indicate engineers how one can 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 wanted to indicate how one can interoperate with current languages resembling Java and C++.

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

Current Materials

Documentation is a key worth of the Rust group and there are lots of nice assets accessible for studying Rust. First, there’s the freely accessible Rust Guide, which covers virtually all the language. Second, the usual library is extensively documented.

As a result of we knew our target market, we may reinforce assumptions than most materials discovered on-line. We created the course for engineers with no less than 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, resembling “management move”, “stack vs heap”, and “strategies”. Folks with different backgrounds can be taught Rust from the various different assets freely accessible on-line.

Expertise

Free of charge-form documentation, mdBook has turn into the de facto commonplace within the Rust group. It’s used for official documentation such because the Rust Guide and Rust Reference.

A very attention-grabbing characteristic is the power to embed executable snippets of Rust code. That is key to creating the coaching partaking for the reason that code might be edited stay and executed straight within the slides:

Along with being a well-known group commonplace, mdBook gives the next necessary options:

• Maintainability: mdbook take a look at 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 instrument as wanted. We relied on this characteristic for translations and ASCII artwork diagrams.

These options made it straightforward for us to decide on mdBook. Whereas mdBook just isn’t designed for displays, 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 international locations. It’s important that they will adapt current Rust code in AOSP to suit their wants. To help translations, we developed mdbook-i18n-helpers. Assist for multilingual documentation has been a group 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 referred to 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 improvement. It consists of interoperability with C, C++, and Java.
• Naked-metal Rust: a full-day class on utilizing Rust for bare-metal improvement. Android gadgets ship important quantities of firmware. These parts 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 (resembling mutexes) and async/await concurrency (cooperative multitasking utilizing futures).

A big set of in-house and group translators have helped translate the course into a number of languages. The total translations had been Brazilian Portuguese and Korean. We’re engaged on Simplified Chinese language and Conventional Chinese language translations as effectively.

Course Reception

We began educating the category in late 2022. In 2023, we employed a vendor, Immunant, to show nearly all of courses for Android engineers. This was necessary for scalability and for high quality: devoted instructors quickly found the place the course contributors 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 contributors agreed it was value their time. Folks constantly informed us that they liked the interactive fashion, 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 stay. Dwell-coding calls for loads from the teacher, however it’s value it as a result of excessive engagement it achieves.

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

We’ve been educating Rust courses at Google for a 12 months now. There are some things that we need to enhance: higher matter ordering, extra workout routines, and extra speaker notes. We’d additionally like to increase the course with extra deep dives. Pull requests are very welcome!

The total course is obtainable without cost at https://google.github.io/comprehensive-rust/. We’re thrilled to see individuals beginning to use Complete Rust for courses all over the world. We hope it may be a helpful useful resource for the Rust group and that it’s going to assist each small and huge groups get began on their Rust journey!

We’re grateful to the 190+ contributors from all around the world who created greater than 1,000 pull requests and points on GitHub. Their bug studies, fixes, and suggestions improved the course in numerous methods. This consists of the 50+ individuals who labored onerous on writing and sustaining the various 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 quite a lot of because of the various volunteer instructors at Google who’ve been spending their time educating courses 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 submit.