Crate hosanna_rs_config 

Shared configuration infrastructure for the hosanna-rs-* family of crates.

This crate provides the two traits and the loader that every downstream component plugs into in order to obtain a uniform configuration pipeline: JSON file for committed defaults, environment variables for per-deployment overrides, business-rule validation, and a typed builder that turns the validated value into a live component (a client, a pool, a bus, …).

The three moving parts

• ComponentConfig — implemented on each component’s Deserialize struct. It declares the environment-variable prefix, the optional JSON file path, and the validate rules.
• ComponentConfigLoader — stateless builder that reads the sources in priority order (env vars override JSON) and returns a validated C: ComponentConfig.
• ComponentBuilder — the async trait that turns the validated config into the live component.

Source priority

From lowest to highest precedence:

1. JSON file at the path returned by ComponentConfig::config_file — silently skipped if the file does not exist.
2. Environment variables prefixed with ComponentConfig::env_prefix and separated by ComponentConfig::env_separator (defaults to "__").

Example — declaring and loading a component config

use hosanna_rs_config::{ComponentConfig, ComponentConfigLoader};
use serde::Deserialize;

#[derive(Debug, Deserialize)]
struct ServerConfig {
    host: String,
    port: u16,
}

impl ComponentConfig for ServerConfig {
    fn env_prefix() -> &'static str { "SERVER" }
    fn config_file() -> Option<&'static str> { Some("config/server") }

    fn validate(&self) -> Result<(), String> {
        if self.port < 1024 {
            return Err(format!("port {} is reserved", self.port));
        }
        Ok(())
    }
}

// Reads `config/server.json` first, then overrides with
// `SERVER__HOST` / `SERVER__PORT` from the environment.
let cfg: ServerConfig = ComponentConfigLoader::<ServerConfig>::new().load()?;

Project conventions

The crate is authored under a strict style that callers can rely on: no unsafe in production code, no free functions in the public surface (every function is a method on a struct or a trait), no unwrap(), no as in use statements, and explicit typing on every public signature.

Re-exports

pub use error::ConfigError;

pub use traits::ComponentBuilder;

pub use traits::ComponentConfig;

pub use types::ComponentConfigLoader;

Modules

error

Error types surfaced by the hosanna-rs-config crate.

traits

The two traits every consumer crate implements.

types

Concrete types exported by the crate.