Get Started

# ===== 1. Install =====
curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh
# Windows: download rustup-init.exe from rustup.rs

# Restart shell. Verify:
rustc --version
cargo --version

# ===== 2. Update + components =====
rustup update
rustup component add clippy rustfmt

# ===== 3. Hello, cargo =====
cargo new hello && cd hello
# Generates Cargo.toml + src/main.rs

# src/main.rs (default):
fn main() {
    println!("Hello, world!");
}

cargo run                # debug build + run
cargo build --release    # optimised binary in target/release/
./target/release/hello

# ===== 4. Adding a dependency =====
cargo add serde --features derive
cargo add serde_json
# Or edit Cargo.toml directly.

# src/main.rs
use serde::Serialize;

#[derive(Serialize)]
struct Order { id: u64, total: u64 }

fn main() {
    let o = Order { id: 1, total: 4995 };
    println!("{}", serde_json::to_string(&o).unwrap());
}

# ===== 5. Tests =====
# src/lib.rs
pub fn add(a: i32, b: i32) -> i32 { a + b }

#[cfg(test)]
mod tests {
    use super::*;
    #[test]
    fn it_adds() { assert_eq!(add(2, 3), 5); }
}

cargo test

# ===== 6. Format + lint =====
cargo fmt
cargo clippy --all-targets -- -D warnings

# ===== 7. A tiny HTTP server (axum) =====
cargo add axum tokio --features tokio/full
cargo add serde_json

// src/main.rs
use axum::{routing::get, Json, Router};
use serde_json::json;

#[tokio::main]
async fn main() {
    let app = Router::new().route("/healthz", get(|| async { Json(json!({"ok": true})) }));
    let listener = tokio::net::TcpListener::bind("0.0.0.0:8080").await.unwrap();
    axum::serve(listener, app).await.unwrap();
}

cargo run --release

# ===== Patterns to internalise =====
# - cargo new + cargo add + cargo run + cargo test = your daily loop
# - cargo fmt on save; cargo clippy in CI with -D warnings
# - Release builds for any benchmark; debug builds lie about performance
# - One repo, one Cargo workspace; sub-crates under members:

# ===== Pitfalls =====
# - Confusing debug vs release perf (debug is 10-100x slower)
# - Skipping clippy; misses many idiomatic improvements
# - Using stable types from nightly crates -> friction later
# - cargo.lock not committed for binaries (commit it for binaries; library crates can skip)

# Install rustup, then:
rustup default stable
cargo --version
cargo new hello && cd hello && cargo run