/**
 * Read a required env var. Throws on startup if missing — never use a default
 * for credentials, hostnames, or anything that should be explicitly configured.
 */
export function requireEnv(name: string): string {
  const v = process.env[name];
  if (!v || v.length === 0) {
    throw new Error(`Missing required environment variable: ${name}`);
  }
  return v;
}

/**
 * Read an optional env var with a non-secret default (e.g. log level, port).
 * NEVER pass a credential or internal hostname as fallback.
 */
export function optionalEnv(name: string, fallback: string): string {
  return process.env[name] || fallback;
}