Configuration (id_effect_config)

Workspace crate id_effect_config loads configuration in a way aligned with Effect.ts configuration: lazy descriptors, optional Figment layering, and low-level effectful reads from a provider installed in R.

Three complementary styles

1. Config<T> descriptors (recommended for parity with Effect Config.*)
   Compose values like Config::string("HOST"), Config::integer("PORT").with_default(3000), then evaluate with Config::load against a concrete provider or Config::run as an Effect with config_env in R.

2. Figment + serde
   Build a Figment (TOML + env + …), then extract / FigmentLayer for whole-document deserialization when you prefer serde-shaped config files.

3. Low-level read_* helpers
   Inject NeedsConfigProvider and call read_string, read_integer, … for imperative-style reads that still stay inside the effect environment.

Wiring

At the stack root, install a config provider service and (for descriptor run) the config_env helper so R: NeedsConfigProvider (and friends) resolve. Combine with Layers the same way as databases or loggers.

Further reading

• cargo doc --open -p id_effect_config — extensive crate-level examples
• Schema for validating structured values after config strings become wire data