customer-riverside/web/sites/default/settings.php

<?php

$databases['default']['default'] = [
  'driver'    => 'pgsql',
  'database'  => getenv('DB_NAME') ?: 'drupal',
  'username'  => getenv('DB_USER') ?: 'drupal',
  'password'  => getenv('DB_PASS') ?: 'drupal',
  'host'      => getenv('DB_HOST') ?: 'postgres',
  'port'      => '5432',
  'prefix'    => '',
  'namespace' => 'Drupal\\pgsql\\Driver\\Database\\pgsql',
  'autoload'  => 'core/modules/pgsql/src/Driver/Database/pgsql/',
];

// Outside the web root — safe from direct HTTP access.
$settings['config_sync_directory'] = '/var/www/html/config/sync';

$settings['hash_salt'] = getenv('HASH_SALT') ?: 'replace-this-in-production';

$settings['update_free_access'] = FALSE;

$is_dev = (bool) getenv('DEBUG');
$postmark_key = getenv('POSTMARK_API_KEY');

if ($is_dev) {
  $config['system.mail']['interface']['default'] = 'php_mail';
} else {
  if (!$postmark_key) {
    throw new \RuntimeException('POSTMARK_API_KEY is not set — refusing to start without a mail transport.');
  }
  $config['system.mail']['interface']['default'] = 'symfony_mailer';
  $config['system.mail']['mailer_dsn'] = [
    'scheme'   => 'postmark+smtp',
    'host'     => 'default',
    'user'     => $postmark_key,
    'password' => NULL,
    'port'     => NULL,
    'options'  => [],
  ];
}

// Disable CSS/JS aggregation — assets served directly from source paths.
$config['system.performance']['css']['preprocess'] = FALSE;
$config['system.performance']['js']['preprocess'] = FALSE;

if (getenv('DEBUG')) {
  $settings['container_yamls'][] = DRUPAL_ROOT . '/sites/development.services.yml';
  $settings['cache']['bins']['render'] = 'cache.backend.null';
  $settings['cache']['bins']['dynamic_page_cache'] = 'cache.backend.null';
  $settings['cache']['bins']['page'] = 'cache.backend.null';
}

// Always allow localhost variants so missing/malformed BASE_URL never locks out local dev.
$settings['trusted_host_patterns'] = ['^localhost$', '^localhost:\d+$', '^127\.0\.0\.1$', '^127\.0\.0\.1:\d+$'];

if ($base = getenv('BASE_URL')) {
  // Ensure scheme is present so parse_url extracts host/port correctly.
  if (!preg_match('#^https?://#', $base)) {
    $base = 'http://' . $base;
  }
  $base_url = $base;
  $parsed   = parse_url($base);
  $host     = $parsed['host'] ?? '';
  $port     = isset($parsed['port']) ? ':' . $parsed['port'] : '';
  if ($host && $host !== 'localhost' && !preg_match('/^127\./', $host)) {
    $settings['trusted_host_patterns'][] = '^' . preg_quote($host . $port, '/') . '$';
  }
}