Class SSHProcess

packages/kaos/src/ssh.ts:216–273

/** Exported for unit tests only. Do not use directly. */
export class SSHProcess implements KaosProcess {
  readonly stdin: Writable;
  readonly stdout: Readable;
  readonly stderr: Readable;
  readonly pid: number = -1;

  private _exitCode: number | null = null;
  private readonly _exitPromise: Promise<number>;
  private readonly _channel: ClientChannel;
  private _disposed = false;

  constructor(channel: ClientChannel) {
    this._channel = channel;
    this.stdin = channel;
    this.stdout = new BufferedReadable(channel as unknown as Readable);
    this.stderr = new BufferedReadable(channel.stderr);

    this._exitPromise = new Promise<number>((resolve) => {
      // Listen to 'close' on the channel, not 'exit', to ensure all
      // buffered output is flushed before we resolve.
      channel.on('close', (code: number | null) => {
        // Some ssh2 backends surface the exit status only on 'close'.
        this._exitCode ??= code ?? 1;
        resolve(this._exitCode);
      });
      channel.on('exit', (code: number | null) => {
        this._exitCode = code ?? 1;
      });
    });
  }

  get exitCode(): number | null {
    return this._exitCode;
  }

  async wait(): Promise<number> {
    return this._exitPromise;
  }

  kill(signal?: NodeJS.Signals): Promise<void> {
    // SSH signals must be stripped of the "SIG" prefix (RFC 4254 §6.9):
    // e.g. 'SIGTERM' → 'TERM', 'SIGKILL' → 'KILL', 'SIGINT' → 'INT'.
    // Honor the caller's requested signal so that remote processes can
    // perform graceful shutdown on SIGTERM/SIGINT.
    const rawSignal = signal ?? 'SIGTERM';
    const sshSignal = rawSignal.startsWith('SIG') ? rawSignal.slice(3) : rawSignal;
    this._channel.signal(sshSignal);
    return Promise.resolve();
  }

  dispose(): void {
    if (this._disposed) return;
    this._disposed = true;
    this.stdin.destroy();
    this.stdout.destroy();
    this.stderr.destroy();
  }
}