Cargo in Rust (Advanced)

In this lesson, you will explore advanced features of Cargo, Rust’s build system and package manager. Cargo does much more than just build and run code.

Advanced Cargo knowledge helps you manage large projects, multiple crates, dependencies, build profiles, and workspaces efficiently.

What Is Cargo?

Cargo is the official tool used to manage Rust projects. It handles:

• Building and compiling code
• Dependency management
• Project structure
• Testing and benchmarking

Every professional Rust project relies heavily on Cargo.

Common Cargo Commands

Before moving into advanced topics, let’s review important Cargo commands.

cargo new my_project
cargo build
cargo run
cargo check
cargo test

Each command serves a specific purpose during development.

Cargo Build Profiles

Cargo supports different build profiles that control how your code is compiled.

The two main profiles are:

• dev – optimized for fast compilation
• release – optimized for performance

cargo build --release

Release builds produce faster executables but take longer to compile.

Customizing Profiles in Cargo.toml

You can customize how Cargo builds your project by editing Cargo.toml.

[profile.dev]
opt-level = 0

[profile.release]
opt-level = 3

This allows fine-grained control over performance and debugging.

Dependency Features

Many crates provide optional features that can be enabled or disabled.

This reduces binary size and improves performance.

[dependencies]
serde = { version = "1.0", features = ["derive"] }

Only the required functionality is included in your build.

Optional Dependencies

Some dependencies can be marked as optional.

[dependencies]
log = { version = "0.4", optional = true }

Optional dependencies are enabled through features.

Cargo Workspaces

A workspace allows you to manage multiple related crates in a single project.

Workspaces share dependencies and build output, improving compile times.

[workspace]
members = [
    "app",
    "utils",
    "core"
]

Running Specific Binaries

A project may contain multiple binary targets.

cargo run --bin app

This allows precise control over which executable is run.

Cargo.lock File

The Cargo.lock file records exact dependency versions.

It ensures consistent builds across machines.

• Commit Cargo.lock for applications
• Ignore it for libraries

Why Advanced Cargo Matters

Advanced Cargo usage helps you:

• Manage large Rust codebases
• Optimize build performance
• Control binary size
• Work with teams effectively

📝 Practice Exercises

Exercise 1

Build a project using the release profile.

Exercise 2

Enable a feature from a dependency.

Exercise 3

Create a workspace with two crates.

Exercise 4

Run a specific binary target.

✅ Practice Answers

Answer 1

cargo build --release

Answer 2

serde = { version = "1.0", features = ["derive"] }

Answer 3

[workspace]
members = ["crate1", "crate2"]

Answer 4

cargo run --bin my_app

What’s Next?

In the next lesson, you will learn about File Handling in Rust, including reading from and writing to files safely.