Add base configuration (#1)

Reviewed-on: #1

src/main.rs

@@ -1,3 +1,50 @@
+use clap::Parser;
+
+/// Basic OpenID test client
+#[derive(Parser, Debug)]
+struct AppConfig {
+    /// Listen URL
+    #[arg(short, long, env, default_value = "0.0.0.0:7510")]
+    listen_addr: String,
+
+    /// Public URL, the URL where this service is accessible, without the trailing slash
+    #[arg(short, long, env, default_value = "http://localhost:7510")]
+    public_url: String,
+
+    /// URL where the OpenID configuration can be found
+    #[arg(short, long, env)]
+    configuration_url: String,
+
+    /// OpenID client ID
+    #[arg(long, env)]
+    client_id: String,
+
+    /// OpenID client secret
+    #[arg(long, env)]
+    client_secret: String,
+}
+
+lazy_static::lazy_static! {
+    static ref CONF: AppConfig = {
+        AppConfig::parse()
+    };
+}
+
 fn main() {
+    env_logger::init_from_env(env_logger::Env::new().default_filter_or("info"));
+
+    log::info!("Will listen on {}", CONF.listen_addr);
+
     println!("Hello, world!");
 }
+
+#[cfg(test)]
+mod test {
+    use crate::AppConfig;
+
+    #[test]
+    fn verify_cli() {
+        use clap::CommandFactory;
+        AppConfig::command().debug_assert();
+    }
+}