remykarem / validate-fields-macro

Compile-time checks to validate struct fields against configurations in application.yml.

Validate fields macro

Compile-time checks in Rust to validate struct fields against configurations in application.yml. Not to be used in production!

• Checks if a struct property exists in the YAML file
• Checks if a YAML mapping exists in the struct
• Checks for missing properties
• Checks for properties up to 2 levels deep only

Based on https://tinkering.xyz/introduction-to-proc-macros.

---

Install

Add the following in Cargo.toml.

[dependencies]
validate_fields_macro = { git = "https://github.com/remykarem/validate-fields-macro" }

We are using the proc_macro_diagnostic feature, which is only available via the nightly release channel. Create a file named rust-toolchain and add the following:

nightly

Usage

Define application.yml.

person:
  name: me
  age: 30

credentials:
  private_key: this_is_some_private_key
  public_key: this_is_some_public_key

Define the structs in src/main.rs.

use validate_fields_macro::validate_fields;

#[validate_fields]
struct Person {
    name: String,
    age: u8,
    email: String,
}

use validate_fields_macro::validate_fields;

#[validate_fields]
struct Credentials<'a> {
    private_key: &'a str,
}

use validate_fields_macro::validate_fields;

#[validate_fields]
struct Client<'a> {
    url: &'a str,
    path: &'a str,
}