Zero to Production Rust Book by Luca Palmieri

Zero to Production Rust Book by Luca Palmieri
API endpoints and request examples
- Health Check
- Subscriptions

This repository is following along the 'Zero2Prod' rust book written by Luca Palmieri. You can find the book and information about the author here.

This readme will likely end up being a collection of points/notes to highlight from the book or research that aren't strictly to do with 'writing the application code'... More around project structure, practice, tooling, things to remember, etc.

Program Flags & Env Vars

Context	Key	Example	Result
Tests	`TEST_LOG`	`TEST_LOG=true cargo test health_check_works	bunyan`

Optimisations on compilation and our inner development loop

Zero2Prod, 1.4.1
https://nnethercote.github.io/perf-book/compile-times.html

Faster linking

Using alternative linker such as lld by the LLVM project for Windows and Linux, zld on MacOS. See .cargo/config.toml for information on setting these up and platform specific configurations. There is a newer linker called mold but at the time of writing the zero2prod book, it seemed a bit early for the author to include it.

Using `cargo-watch`

We can also mitigate the impact on our productivity by reducing the perceived compilation time - i.e. the time you spend looking at your terminal waiting for cargo check or cargo run to complete.

cargo install cargo-watch

You can use cargo watch to perform cargo commands on file change, this includes chaining commands - such as check, test and run.

cargo watch -x check
cargo watch -x check -x test -x run

Using `cargo tarpaulin`

tarpaulin is a cargo subcommand that measures code coverage, while not a great metric on quality, it is a good way to see untested areas of the codebase.

# At the time of writing tarpaulin only supports
# x86_64 CPU architectures running Linux.
cargo install cargo-tarpaulin

cargo tarpaulin --ignore-tests

Linting rust code

You can lint rust code using clippy, a component of the rustup toolchain.

rustup component add clippy

# Running clippy
cargo clippy
# Running clippy and exiting with non-zero code on warnings, useful for CI
cargo clippy -- -D warnings

Sometimes there can be linting issues clippy detects that aren't actually problematic, in those cases we can instruct clippy to ignore that code block with the following attribute: #[allow(clippy::lint_name)].

There is also a clippy.toml config that can be added to the project as well as project level directives such as #![allow(clippy::lint_name)].

Formatting rust code

rustup component add rustfmt

# Running cargo fmt
cargo fmt
# Running cargo fmt checks, useful for CI
cargo fmt -- --check

You can tune to the formatter to fit the project by adding a rustfmt.toml configuration file.

Vulnerability scanning of dependencies

There is an advisory database maintained by 'The Rust Secure Code' working group, using the cargo-audit subcommand we can check if any vulnerabilities have been reported in any of the dependencies our project has.

cargo install cargo-audit

cargo audit

Other tooling

Cargo Expand

cargo-expand is a cargo subcommand that expands all macros and code generation without passing the output to the compiler, which allows us to inspect and debug the code that we use but otherwise would not see.

cargo install cargo-expand

cargo expand

Cargo unused dependency management (`cargo-udeps`)

cargo-udeps scans the Cargo.toml file and checks if all of the crates listed under dependencies have actually been used in the project. cargo-udeps requires the nightly compiler, we can add +nightly to the invocation to tell cargo explicitly what toolchain we want to use.

cargo install cargo-udeps

cargo +nightly udeps

API endpoints and request examples

Health Check

curl http://127.0.0.1:8000/health_check -v

Subscriptions

curl -X POST -d "name=hello%20world&email=helloworld%40example.com" http://127.0.0.1:8000/subscriptions

hexnaught/z2p