tier-derive

tier-derive provides #[derive(TierConfig)] for the tier Rust configuration library.

Use it when you want config metadata to stay next to your serde types instead of being repeated in manual builder code. It derives env names, aliases, examples, validation rules, merge behavior, and secret handling from the same type definitions you already use for deserialization.

It generates structured TierMetadata implementations for nested config structs, newtype wrappers, and serde-driven enums.

Supported metadata includes:

• field attributes such as secret, env, doc, example, deprecated, and merge
• declared validation such as non_empty, numeric and length bounds, one_of, hostname/IP/socket/path rules, and cross-field checks
• serde-aware naming and shape rules including rename, rename_all, rename_all_fields, alias, default, tagging, skip, and flatten
• automatic tier::Secret<T> detection

Most users should depend on tier with the derive feature enabled and use the re-exported tier::TierConfig derive macro.