Cargo (package manager) and tools

cargo help or cargo <command> --help

cargo --version

# Create a new project. Can add --bin  or --lib
cargo new hello_cargo

# Creates an executable file in target/debug/hello_cargo
cargo build
cargo build --release

# Build and run a project in one step
cargo run

# Pass arguments to the program and collect output
cargo run -- arg1 somefile.txt > output.txt

# Quickly checks your code to make sure it compiles but doesn’t produce an executable
cargo check

# Removes build artifacts
cargo clean

# Looks for tests to run in two places: in each of your src files and any tests in tests/.
cargo test

# Updates all dependencies - respect the SemVer constraints in cargo.toml
cargo update
# Updates just “regex”
cargo update -p regex

`Cargo.toml` and lock files

# Configure the package
[package]
name = "hello_cargo"
version = "0.1.0"
edition = "2021"

# See more keys and their definitions at
# https://doc.rust-lang.org/cargo/reference/manifest.html

[dependencies]

# Reference a crate in crates.io
time = "0.1.12"
# This is equivalent to the ^0.1.12 SemVer version range.
# `cargo update -p time` should update to version 0.1.13 if it is the latest 0.1.z release,
# but would not update to 0.2.0

# Reference a Git repo
regex = { git = "https://github.com/rust-lang/regex.git" }

# Reference a sub-crate
# Points to folder `hello_utils`, inside of which a `Cargo.toml` and `src` folder
hello_utils = { path = "hello_utils", version = "0.1.0" }

Examples of version requirements and the versions that would be allowed with them:

1.2.3  :=  >=1.2.3, <2.0.0
1.2    :=  >=1.2.0, <2.0.0
1      :=  >=1.0.0, <2.0.0
0.2.3  :=  >=0.2.3, <0.3.0
0.2    :=  >=0.2.0, <0.3.0
0.0.3  :=  >=0.0.3, <0.0.4
0.0    :=  >=0.0.0, <0.1.0
0      :=  >=0.0.0, <1.0.0

Details in https://doc.rust-lang.org/cargo/reference/specifying-dependencies.html⮳

If you’re building a non-end product, such as a rust library that other rust packages will depend on, put Cargo.lock in your .gitignore.

If you’re building an end product, which are executable like command-line tool or an application, or a system library with crate-type of staticlib or cdylib, check Cargo.lock into git.

# Install if needed
cargo install cargo-edit

# Add dependencies to Cargo.toml from the command line
cargo add actix-web@4.0.0

cargo-watch

cargo install cargo-watch

# Runs `cargo check` after every code change
cargo watch -x check

# Run cargo check after code changes.
# If it succeeds, it launches cargo test.
# If tests pass, it launches the application with cargo run.
cargo watch -x check -x test -x run

Formatting

# Install `rustfmt` if needed
rustup component add rustfmt

cargo fmt

# Fails if code is not formatted; use in CD / CI
cargo fmt -- --check

Linting

rustup component add clippy # install if needed
cargo clippy

Mute a warning using the #[allow(clippy::lint_name)] attributes

Fix

Can automatically fix compiler warnings that have a clear way to correct the problem that’s likely what you want.

cargo fix

Code coverage

Tarpaulin⮳

Security audit

cargo install cargo-audit
cargo audit

Unused dependencies

udeps⮳

or (simpler) Machete⮳

cargo install cargo-machete
cargo machete

Templates

Cargo Generate⮳ is a developer tool to help you get up and running quickly with a new Rust project by leveraging a pre-existing git repository as a template.

Rust How-to