rustfmt.md

How Firecracker Format Their Rust Code

Like most Rust projects, Firecracker uses cargo fmt (namely rustfmt) to format Rust code.

This rule is applied bu executing the pre-commit shell script, and enforced in their CI.

pre-commit Script

This script lints every staged file, as of .rss, it apply cargo fmt on them. The command directly formats that file instead of produce differences before/after format.

Install rustfmt

rustfmt (invoked by cargo fmt command) could be installed with:

rustup component add rustfmt

And we can then use it with command:

cargo fmt

Nightly Toolchain

Sometimes we need unstable options of rustfmt, e.g. group_imports and the like. These options are not available in stable channel, thus we need to install nightly channel:

rustup component add rustfmt --toolchain nightly

Then we can use nightly rustfmt with:

cargo +nightly fmt