Function installLogging

packages/computerd/src/cli/logger.ts:75–112

(logFilePath: string | undefined)

// original console methods, and closes the file handle. Calling it
// is optional — the OS closes the fd on process exit anyway.
export function installLogging(logFilePath: string | undefined): () => void {
  const file: FileLogger | undefined =
    logFilePath !== undefined && logFilePath !== "" ? createFileLogger(logFilePath) : undefined;
  // Save the original methods unbound so teardown can restore the
  // exact same references the caller had pre-install. The wrappers
  // call through bind() copies so they don't reenter themselves.
  const originalLog = console.log;
  const originalError = console.error;
  const callLog = originalLog.bind(console);
  const callError = originalError.bind(console);
  const writeBoth = (level: LogLevel, original: (...args: unknown[]) => void) => {
    return (...args: unknown[]): void => {
      original(...args);
      file?.write(level, args);
    };
  };
  console.log = writeBoth("info", callLog);
  console.error = writeBoth("error", callError);

  const onUncaught = (err: unknown): void => {
    console.error("uncaughtException:", err);
    process.exit(1);
  };
  const onUnhandled = (reason: unknown): void => {
    console.error("unhandledRejection:", reason);
    process.exit(1);
  };
  process.on("uncaughtException", onUncaught);
  process.on("unhandledRejection", onUnhandled);

  return () => {
    process.off("uncaughtException", onUncaught);
    process.off("unhandledRejection", onUnhandled);
    console.log = originalLog;
    console.error = originalError;
    file?.close();
  };
}