zero2prod/src/configuration.rs

use crate::domain::SubscriberEmail;
use anyhow::Context;
use secrecy::{ExposeSecret, SecretString};
use serde::Deserialize;
use serde_aux::field_attributes::deserialize_number_from_string;
use sqlx::postgres::{PgConnectOptions, PgSslMode};
use tower_sessions_redis_store::{
    RedisStore,
    fred::prelude::{ClientLike, Pool},
};

pub fn get_configuration() -> Result<Settings, config::ConfigError> {
    let base_path = std::env::current_dir().expect("Failed to determine the current directory");
    let config_dir = base_path.join("configuration");
    let environment: Environment = std::env::var("APP_ENVIRONMENT")
        .unwrap_or_else(|_| "local".into())
        .try_into()
        .expect("Failed to parse APP_ENVIRONMENT");
    let environment_filename = format!("{}.yaml", environment.as_str());

    let settings = config::Config::builder()
        .add_source(config::File::from(config_dir.join("base.yaml")))
        .add_source(config::File::from(config_dir.join(environment_filename)))
        .add_source(
            config::Environment::with_prefix("APP")
                .prefix_separator("_")
                .separator("__"),
        )
        .build()?;

    settings.try_deserialize::<Settings>()
}

pub enum Environment {
    Local,
    Production,
}

impl Environment {
    pub fn as_str(&self) -> &str {
        match self {
            Environment::Local => "local",
            Environment::Production => "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(Environment::Local),
            "production" => Ok(Environment::Production),
            other => Err(format!(
                "{} is not a supported environment. Use either `local` or `production`.",
                other
            )),
        }
    }
}

#[derive(Clone, Deserialize)]
pub struct Settings {
    pub application: ApplicationSettings,
    pub database: DatabaseSettings,
    pub email_client: EmailClientSettings,
    pub kv_store: RedisSettings,
}

#[derive(Clone, Deserialize)]
pub struct ApplicationSettings {
    #[serde(deserialize_with = "deserialize_number_from_string")]
    pub port: u16,
    pub host: String,
    pub base_url: String,
}

#[derive(Clone, Deserialize)]
pub struct EmailClientSettings {
    pub base_url: String,
    sender_email: String,
    pub authorization_token: SecretString,
    pub timeout_milliseconds: u64,
}

impl EmailClientSettings {
    pub fn sender(&self) -> Result<SubscriberEmail, anyhow::Error> {
        SubscriberEmail::parse(self.sender_email.clone())
    }

    pub fn new(
        base_url: String,
        sender_email: String,
        authorization_token: String,
        timeout_milliseconds: u64,
    ) -> Self {
        let authorization_token = SecretString::from(authorization_token);
        Self {
            base_url,
            sender_email,
            authorization_token,
            timeout_milliseconds,
        }
    }
}

#[derive(Clone, Deserialize)]
pub struct RedisSettings {
    pub host: String,
    pub port: u16,
}

impl RedisSettings {
    pub fn connection_string(&self) -> String {
        format!("redis://{}:{}", self.host, self.port)
    }

    pub async fn session_store(&self) -> Result<RedisStore<Pool>, anyhow::Error> {
        let pool = Pool::new(
            tower_sessions_redis_store::fred::prelude::Config::from_url(&self.connection_string())
                .context("Failed to parse Redis URL string.")?,
            None,
            None,
            None,
            6,
        )
        .unwrap();
        pool.connect();
        pool.wait_for_connect()
            .await
            .context("Failed to connect to the Redis server.")?;
        Ok(RedisStore::new(pool))
    }
}

#[derive(Clone, Deserialize)]
pub struct DatabaseSettings {
    pub username: String,
    pub password: SecretString,
    #[serde(deserialize_with = "deserialize_number_from_string")]
    pub port: u16,
    pub host: String,
    pub database_name: String,
    pub require_ssl: bool,
    pub timeout_milliseconds: u64,
}

impl DatabaseSettings {
    pub fn with_db(&self) -> PgConnectOptions {
        self.without_db().database(&self.database_name)
    }

    pub fn without_db(&self) -> PgConnectOptions {
        let ssl_mode = if self.require_ssl {
            PgSslMode::Require
        } else {
            PgSslMode::Prefer
        };
        PgConnectOptions::new()
            .host(&self.host)
            .username(&self.username)
            .password(self.password.expose_secret())
            .port(self.port)
            .ssl_mode(ssl_mode)
    }
}