BotDiscord/src/config.rs

use dotenvy::dotenv;
use serde::Deserialize;
use std::env;
use std::fs::read_to_string;
use std::path::PathBuf;

const PERSISTENCE_HOST: &str = "PERSISTENCE_HOST";
const PERSISTENCE_PORT: &str = "PERSISTENCE_PORT";
const PERSISTENCE_USER: &str = "PERSISTENCE_USER";
const PERSISTENCE_PWD: &str = "PERSISTENCE_PWD";
const PERSISTENCE_DB: &str = "PERSISTENCE_DB";
const PERSISTENCE_TLS: &str = "PERSISTENCE_TLS";
const PERSISTENCE_TLS_INSECURE: &str = "PERSISTENCE_TLS_INSECURE";
const BOT_NAME: &str = "BOT_NAME";

const BOT_TOKEN: &str = "BOT_TOKEN";
const BOT_PREFIX: &str = "BOT_PREFIX";

const RUST_ENV: &str = "RUST_ENV";

const PORT: &str = "PORT";

#[derive(Deserialize, Clone)]
pub struct Config {
    pub bot_name: String,
    pub persistence: PersistenceConfig,
    pub env: String,
    pub port: u16,
    pub token: String,
    pub prefix: String,
}

#[derive(Deserialize, Clone)]
pub struct PersistenceConfig {
    pub host: String,
    pub port: Option<u16>,
    pub user: String,
    pub password: String,
    pub database: String,
    pub tls: Option<bool>,
    pub tls_insecure: Option<bool>,
}

pub fn parse_local_config() -> Config {
    let mut d = PathBuf::from(env!("CARGO_MANIFEST_DIR"));
    println!(env!("CARGO_MANIFEST_DIR"));
    d.push("resources/config.toml");
    match dotenv() {
        Ok(_) => println!("Loaded .env file"),
        Err(err) => println!("No .env file found: {:?}", err),
    }
    parse_config(d)
}

#[allow(dead_code)]
pub fn parse_test_config() -> Config {
    let mut d = PathBuf::from(env!("CARGO_MANIFEST_DIR"));
    d.push("resources/test_config.toml");
    parse_config(d)
}

pub fn parse_config(path_buf: PathBuf) -> Config {
    let config: Config = parse_config_from_file(path_buf);
    override_config_with_env_vars(config)
}

fn parse_config_from_file(path_buf: PathBuf) -> Config {
    let config_file = path_buf.into_os_string().into_string().unwrap();
    toml::from_str(read_to_string(config_file).unwrap().as_str()).unwrap()
}

fn override_config_with_env_vars(config: Config) -> Config {
    let pers = config.persistence;

    Config {
        bot_name: env::var(BOT_NAME).unwrap_or(config.bot_name),
        env: env::var(RUST_ENV).unwrap_or(config.env),
        token: env::var(BOT_TOKEN).unwrap_or(config.token),
        prefix: env::var(BOT_PREFIX).unwrap_or(config.prefix),
        port: env::var(PORT)
            .unwrap_or(config.port.to_string())
            .parse::<u16>()
            .unwrap(),
        persistence: PersistenceConfig {
            host: env::var(PERSISTENCE_HOST).unwrap_or(pers.host),
            port: env::var(PERSISTENCE_PORT)
                .map(|p| {
                    p.parse::<u16>()
                        .expect("Cannot parse the received persistence port")
                })
                .ok()
                .or(pers.port),
            user: env::var(PERSISTENCE_USER).unwrap_or(pers.user),
            password: env::var(PERSISTENCE_PWD).unwrap_or(pers.password),
            database: env::var(PERSISTENCE_DB).unwrap_or(pers.database),
            tls: env::var(PERSISTENCE_TLS)
                .map(|p| {
                    p.parse::<bool>()
                        .expect("Cannot parse the received persistence tls")
                })
                .ok()
                .or(pers.tls),
            tls_insecure: env::var(PERSISTENCE_TLS_INSECURE)
                .map(|p| {
                    p.parse::<bool>()
                        .expect("Cannot parse the received persistence tls")
                })
                .ok()
                .or(pers.tls_insecure),
        },
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::config::parse_config;
    use serial_test::serial;
    use std::env;
    use std::path::PathBuf;

    #[test]
    #[serial(config)]
    fn should_parse_a_config() {
        let mut d = PathBuf::from(env!("CARGO_MANIFEST_DIR"));
        d.push("resources/test_config.toml");
        let config = parse_config(d);
        let pers = config.persistence;

        assert_eq!("localhost", pers.host);
        assert_eq!(5433, pers.port.unwrap());
        assert_eq!("GB8eE8vh", pers.user);
        assert_eq!("1OLlRZo1tnNluvx", pers.password);
        assert_eq!("1pNkVsX3FgFeiQdga", pers.database);
        assert_eq!(Some(false), pers.tls);
        assert_eq!(Some(false), pers.tls_insecure);
    }

    #[test]
    #[serial(config)]
    fn should_override_a_parsed_config_with_env_vars() {
        env::set_var(PERSISTENCE_HOST, "my_host");
        env::set_var(PERSISTENCE_PORT, "1111");
        env::set_var(PERSISTENCE_USER, "just_me");
        env::set_var(PERSISTENCE_PWD, "what_a_pwd");
        env::set_var(PERSISTENCE_DB, "my_db");
        env::set_var(PERSISTENCE_TLS, "true");
        env::set_var(PERSISTENCE_TLS_INSECURE, "true");

        let mut d = PathBuf::from(env!("CARGO_MANIFEST_DIR"));
        d.push("resources/test_config.toml");
        let config = parse_config(d);
        let pers = config.persistence;

        assert_eq!("my_host", pers.host);
        assert_eq!(1111, pers.port.unwrap());
        assert_eq!("just_me", pers.user);
        assert_eq!("what_a_pwd", pers.password);
        assert_eq!("my_db", pers.database);
        assert_eq!(Some(true), pers.tls);
        assert_eq!(Some(true), pers.tls_insecure);

        // reset env vars
        env::remove_var(PERSISTENCE_HOST);
        env::remove_var(PERSISTENCE_PORT);
        env::remove_var(PERSISTENCE_USER);
        env::remove_var(PERSISTENCE_PWD);
        env::remove_var(PERSISTENCE_DB);
        env::remove_var(PERSISTENCE_TLS);
        env::remove_var(PERSISTENCE_TLS_INSECURE);
    }
}