Mastering Rust - Second Edition

Cargo and dependencies

For projects that depend on other libraries, the package manager has to find all of the direct dependencies in the project and also any indirect dependencies, and then compile and link them to the project. Package managers are not just a tool for facilitating dependency resolution; they should also ensure predictable and reproducible builds of a project. Before we cover building and running our project, let's discuss how Cargo manages dependencies and ensures repeatable builds.

A Rust project managed with Cargo has two files through which it does all its magic: Cargo.toml (introduced before) is the file where you, as the developer, write dependencies and their needed versions with SemVer syntax (like 1.3.*), and a lock ...