is-up?

Or, "baby's first Rust project."

The purpose of this project is exclusively as an accelerated first dive into Rust.

Areas of Review

General structure. From the file system, to the commands/ directory, and bigger picture decisions like the daemon being separate binary (see: daemon.rs and Cargo.toml).

Idiomatic Rust

• In is_up.rs, I've made a few decisions I'm not proud of with respect to composability. A similar pattern in configuration.rs.
• In is_up.rs, the handler function exists solely to turn a complex error type into a string. I don't love the pattern.
• Some challenges with the use of enums/abstract types. Looking for broad feedback on how to do that better.
• Identify some sane rules-of-thumb for where to use .expect, ? and match.
• Appropriate file structure. Looking for idiomatic feedback/great projects to learn from here.
• Traits and implementations on objects. I'm not yet sure how to balance the object-oriented approach these features offer with the functional approach I generally prefer.

Language Features

• Use of closures. In main.rs, I had initially used a closure to capture the config file, but it didn't feel very Rusty.
• Use of scoping rules like lifetimes. I have not wrapped my mind around lifetimes at all yet.

Testing Culture

I've run into some challenges with writing adequate tests in Rust.

• Culturally, I am unsure if we should prefer carefully structured mocks or a full dependency injection style.
• Mocking the HTTP requests proved to be a minor challenge.
• No clear way to generate coverage reports.
• Testing libraries yet to be explored. How to broadly do nice assertions?

Other

• Use of the nightly build appears to be very common in Rust to enable certain compiler features (e.g., Mocktopus required it).
• I'm finding a lot of loss of encapsulation problems. For example, main.rs has the extern statements and the macros that are only used in other files.