Class PythonWorker

src/python/worker.ts:19–310

export { MAX_STDERR_BUFFER_LENGTH } from './stderr';

export class PythonWorker {
  private process: PythonShell | null = null;
  private ready: boolean = false;
  private busy: boolean = false;
  private shuttingDown: boolean = false;
  private crashCount: number = 0;
  private stderrLogger = new PythonStderrLogger('Python worker stderr: ');
  private readonly maxCrashes: number = 3;
  private pendingRequest: {
    responseFile: string;
    resolve: (result: unknown) => void;
    reject: (error: Error) => void;
  } | null = null;
  private requestTimeout: NodeJS.Timeout | null = null;

  constructor(
    private scriptPath: string,
    private functionName: string,
    private pythonPath?: string,
    private timeout: number = getRequestTimeoutMs(),
    private onReady?: () => void,
  ) {}

  async initialize(): Promise<void> {
    return this.startWorker();
  }

  private async startWorker(): Promise<void> {
    const wrapperPath = path.join(getWrapperDir('python'), 'persistent_wrapper.py');

    // Validate and resolve Python path using smart detection (tries python3, then python)
    const resolvedPythonPath = await validatePythonPath(
      this.pythonPath || 'python',
      typeof this.pythonPath === 'string',
    );

    this.process = new PythonShell(wrapperPath, {
      mode: 'text',
      pythonPath: resolvedPythonPath,
      args: [this.scriptPath, this.functionName],
      stdio: ['pipe', 'pipe', 'pipe'],
    });

    // Listen for READY signal
    return new Promise((resolve, reject) => {
      const readyTimeout = setTimeout(() => {
        // Kill the process to prevent orphaned Python processes
        // and avoid triggering handleCrash() which would retry
        this.shuttingDown = true;
        if (this.process) {
          this.process.kill('SIGTERM');
          this.process = null;
        }
        reject(new Error('Worker failed to become ready within timeout'));
      }, 30000);

      this.process!.on('message', (message: string) => {
        if (message.trim() === 'READY') {