GoKawiilThis blog post describes an idea I’ve been kicking around called battery packs. Battery packs are a curated set of crates arranged around a common theme. For example, there’s a CLI battery pack that has everything you need to build a great CLI, an opinionated pack for creating a backend web service, and one for embedded development (based on the Embedded Working Group’s Awesome Rust repository). We’ve also got some smaller ones, such as the error-handling battery pack that shows how to handle errors in Rust. But this is just the beginning – a key part of the battery pack design is that anybody can create one.
Battery packs are meant to address one of the most common things I hear from new Rust adopters. Everyone loves the wealth of high-quality crates available on crates.io. And everyone hates having to spend a bunch of time researching and comparing alternatives. Battery packs can serve as a good set of default choices. And they don’t lock you in. At heart, they’re basically just a list of recommended crates, so you can always swap something out if you find an alternative.
We’ve got a prototype of the battery pack tool working today, so you can try it out if you’re curious. Just run cargo install cargo-bp and then try a few commands! For example,
> cargo bp list
will show you the set of available battery packs, based on a crates.io search (as I’ll explain below, a battery pack is itself packaged and distributed as a crate, but not one that you take a direct dependency on). And cargo bp add will add batteries from a battery pack into your crate, so e.g.
> cargo bp add cli
would let you select and add common CLI libraries. If you want to see a more involved demo, try out cargo bp add embedded , which is derived from the Awesome Embedded Rust repository.
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One of the key ideas from battery packs is that anybody can publish one. They are just a crate named X-battery-pack ; the dependencies of that crate are your recommendations. Features are designations of common sets of crates frequently used together. The examples are your templates. And so forth.
Letting anybody create a battery pack is in contrast to the previous ideas for an “extended standard library for Rust”, and it is intended to address some of Rust’s unique challenges. For one thing, it lets people publish battery packs that are tailored to specific requirements. For example, the CLI and backend service battery packs are targeting a “typical computer”. But I could imagine the Rust embedded working group publishing a battery pack with libraries focused on no-std and binary size optimization.
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