zero2prod/src/config.rs

use std::fmt::Display;

use secrecy::{ExposeSecret, Secret};
use serde::Deserialize;

#[derive(Debug, Deserialize)]
pub struct Settings {
    pub database: DatabaseSettings,
    pub application: ApplicationSettings,
}

#[derive(Debug, Deserialize)]
pub struct DatabaseSettings {
    pub username: String,
    pub password: Secret<String>,
    pub port: u16,
    pub host: String,
    pub database_name: String,
}
#[derive(Debug, Deserialize)]
pub struct ApplicationSettings {
    pub port: u16,
    pub host: String,
}

impl DatabaseSettings {
    pub fn to_string_no_db(&self) -> Secret<String> {
        Secret::new(format!(
            "postgres://{}:{}@{}:{}",
            self.username,
            self.password.expose_secret(),
            self.host,
            self.port
        ))
    }
    pub fn to_string(&self) -> Secret<String> {
        Secret::new(format!(
            "postgres://{}:{}@{}:{}/{}",
            self.username,
            self.password.expose_secret(),
            self.host,
            self.port,
            self.database_name
        ))
    }
}

pub fn get_config() -> Result<Settings, config::ConfigError> {
    let base_path = std::env::current_dir().expect("Failed to determine current directory");
    let config_directory = base_path.join("config");
    let env: Environment = std::env::var("APP_ENVIRONMENT")
        .unwrap_or_else(|_| "local".into())
        .try_into()
        .expect("Failed to parse APP_ENVIRONMENT");

    let env_filename = format!("{}.toml", &env);

    let settings = config::Config::builder()
        .add_source(config::File::from(config_directory.join("base.toml")))
        .add_source(config::File::from(config_directory.join(env_filename)))
        .build()?;
    settings.try_deserialize::<Settings>()
}

#[derive(Debug)]
pub enum Environment {
    Local,
    Production,
}

impl Display for Environment {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        match self {
            Environment::Local => write!(f, "local"),
            Environment::Production => write!(f, "production"),
        }
    }
}

impl TryFrom<String> for Environment {
    type Error = String;
    fn try_from(value: String) -> Result<Self, Self::Error> {
        match value.to_lowercase().as_str() {
            "local" => Ok(Self::Local),
            "production" => Ok(Self::Production),
            other => Err(format!(
                "{} is not supported environment. \
                Use either `local` or `production`.",
                other
            )),
        }
    }
}