#103 Using Cargo

Using Cargo to create and manage a rust project.

Notes

Cargo is the Rust package manager:

• generates project skeletons
• downloads package dependencies
• compiles your packages
• makes distributable packages
• uploads distributions to crates.io, the Rust community’s package registry

i.e. similar to bundler and rubygems in the Ruby world.

Making a Project with Cargo

$ cargo new helloc
     Created binary (application) `helloc` package
$ cd helloc/

Generated files:

• helloc/Cargo.toml - package manifest
• helloc/src/main.rs - main source file (hello world placeholder)

Building and Run:

$ cargo build
   Compiling helloc v0.1.0 (.../project_with_cargo/helloc)
    Finished dev [unoptimized + debuginfo] target(s) in 1.61s
$ target/debug/helloc
Hello, world!

Alternatively, use cargo run to update compilation and run (like using a makefile)

$ cargo run
    Finished dev [unoptimized + debuginfo] target(s) in 0.08s
     Running `target/debug/helloc`
Hello, world!

Build for release

$ cargo build --release
   Compiling helloc v0.1.0 (.../project_with_cargo/helloc)
    Finished release [optimized] target(s) in 1.48s

Adding Dependencies

I’ve picked the rand crate for a simple example. Adding to the manifest:

[dependencies]
rand = "0.7"

Running cargo installs the dependency and builds the updated project (which exercises some basic random capabilities):

$ cargo run
    Finished dev [unoptimized + debuginfo] target(s) in 0.02s
     Running `target/debug/helloc`
Using the rand crate
--------------------
Random unsigned 8-bit number: 47
Random boolean: true
Random choice of direction: ⬋
Unshuffled numbers: [1, 2, 3, 4, 5]
Shuffled: [2, 4, 5, 1, 3]

Credits and References

• The Cargo Book
• The Rust community crate registry
• TOML (Tom’s Obvious, Minimal Language) - Cargo configuration format
• crate: rand
• The Rust Rand Book