Function buildDSNFromSource

src/config/toml-loader.ts:831–931

(source: SourceConfig)

 * Similar to buildDSNFromEnvParams in env.ts but for TOML sources
 */
export function buildDSNFromSource(source: SourceConfig): string {
  // If DSN is already provided, use it — but merge in dual-home fields
  // (sslmode/sslrootcert/instanceName/authentication/domain) so they actually
  // affect the connection. Conflicts between the DSN query string and these
  // fields are rejected at validation time, so any param already present in the
  // DSN is guaranteed to match.
  if (source.dsn) {
    return mergeSourceFieldsIntoDSN(source.dsn, source);
  }

  // Validate required fields
  if (!source.type) {
    throw new Error(
      `Source '${source.id}': 'type' field is required when 'dsn' is not provided`
    );
  }

  // Handle SQLite
  if (source.type === "sqlite") {
    if (!source.database) {
      throw new Error(
        `Source '${source.id}': 'database' field is required for SQLite`
      );
    }
    return `sqlite:///${source.database}`;
  }

  // For other databases, require host, user, database
  // Password is optional for Azure AD access token authentication and AWS IAM auth
  const isAwsIamPasswordless =
    source.aws_iam_auth === true &&
    ["postgres", "mysql", "mariadb"].includes(source.type);
  const passwordRequired =
    source.authentication !== "azure-active-directory-access-token" &&
    !isAwsIamPasswordless;
  if (!source.host || !source.user || !source.database) {
    throw new Error(
      `Source '${source.id}': missing required connection parameters. ` +
        `Required: type, host, user, database`
    );
  }
  if (passwordRequired && !source.password) {
    throw new Error(
      `Source '${source.id}': password is required. ` +
        `(Password is optional for azure-active-directory-access-token authentication ` +
        `or when aws_iam_auth=true)`
    );
  }

  // Determine default port if not specified
  const port = source.port || getDefaultPortForType(source.type);

  if (!port) {
    throw new Error(`Source '${source.id}': unable to determine port`);
  }

  // Encode credentials
  const encodedUser = encodeURIComponent(source.user);