Trait PluginOption

Source

pub trait PluginOption {
    type Value: FromStr;

    const NAME: &'static str;
    const DOC: &'static str;
    const DEFAULT: &'static str;
    const KIND: OptionKind;
}

Expand description

A plugin-defined scalar option — a typed view over the config register/read wire (slice PH7.10b). Implement via #[derive(PluginOption)] on a newtype over bool / i64 / String; #[option(default = "...")] is required, #[option(name = "...")] defaults to the kebab-cased type name. For structured (record / list / enum) options use shape::ConfigShape instead.

It is WIT-agnostic (approach A): the derive only supplies these constants plus the value type. The plugin makes the config.register-option / config.get-option WIT calls itself, mapping OptionKind to the generated option-type (config below stands in for a plugin’s generated bindings):

use lattice_plugin_sdk::{OptionKind, PluginOption, parse_option};

/// How many things the plugin tracks.
#[derive(PluginOption)]
#[option(name = "myplugin.count", default = "3")]
struct Count(i64);

// The one per-plugin mapping to the generated WIT enum.
fn wit_ty(kind: OptionKind) -> config::OptionType {
    match kind {
        OptionKind::Boolean => config::OptionType::Boolean,
        OptionKind::Integer => config::OptionType::Integer,
        OptionKind::String => config::OptionType::String,
    }
}

config::register_option(Count::NAME, wit_ty(Count::KIND), Count::DEFAULT, Count::DOC);
let value: i64 = parse_option::<Count>(&config::get_option(Count::NAME).unwrap()).unwrap();

assert_eq!(value, 5);
assert_eq!(Count::NAME, "myplugin.count");
assert_eq!(Count::KIND, OptionKind::Integer);
assert_eq!(Count::DOC, "How many things the plugin tracks.");