Crate premortem_derive 

Derive macros for the premortem configuration validation library.

This crate provides the #[derive(Validate)] macro that generates Validate trait implementations using stillwater’s Validation::all() pattern for error accumulation.

Basic Usage

use premortem::Validate;

#[derive(Validate)]
struct ServerConfig {
    #[validate(non_empty)]
    host: String,

    #[validate(range(1..=65535))]
    port: u16,
}

Available Validators

String Validators

• non_empty - Value cannot be empty
• min_length(n) - Minimum string length
• max_length(n) - Maximum string length
• length(n..=m) - String length in range
• pattern("regex") - Match regex pattern
• email - Valid email format
• url - Valid URL format
• ip - Valid IP address
• uuid - Valid UUID format

Numeric Validators

• range(n..=m) - Value in range
• positive - Value > 0
• negative - Value < 0
• non_zero - Value != 0

Path Validators

• file_exists - File exists at path
• dir_exists - Directory exists at path
• parent_exists - Parent directory exists
• extension("ext") - File has extension

Collection Validators

• each(validator) - Apply validator to each element

Structural Validators

• nested - Validate nested struct
• skip - Skip validation for this field
• custom = "fn_name" - Call custom validation function

Control Flow

• when = "condition" - Conditional validation
• message = "custom message" - Override error message

Sensitive Fields

Use #[sensitive] to redact field values in error messages:

#[derive(Validate)]
struct Credentials {
    #[sensitive]
    #[validate(min_length(8))]
    password: String,
}

Struct-Level Validation

Use #[validate(custom = "fn_name")] on the struct for cross-field validation:

#[derive(Validate)]
#[validate(custom = "validate_config")]
struct Config {
    start_port: u16,
    end_port: u16,
}

fn validate_config(cfg: &Config) -> ConfigValidation<()> {
    if cfg.start_port < cfg.end_port {
        Validation::Success(())
    } else {
        Validation::fail_with(ConfigError::CrossFieldError {
            paths: vec!["start_port".into(), "end_port".into()],
            message: "start_port must be less than end_port".into(),
        })
    }
}

Derive Macros

Validate

Derive the Validate trait for a struct.