Class PythonProcessRunner

electron/main/process-runner.ts:159–250

// Protocol — stdout: JSON lines     { type: 'progress'|'log'|'done'|'error', ... }

export class PythonProcessRunner implements IProcessRunner {
  private pythonExe:    string
  private scriptPath:   string
  private workspaceDir: string
  private tempDir:      string

  constructor(pythonExe: string, extDir: string, entry: string, workspaceDir: string, tempDir: string) {
    this.pythonExe    = pythonExe
    this.scriptPath   = join(extDir, entry)
    this.workspaceDir = workspaceDir
    this.tempDir      = tempDir
  }

  async run(
    input:  ProcessInput,
    params: Record<string, unknown>,
    onProgress?: (percent: number, label: string) => void,
    onLog?:      (message: string) => void,
  ): Promise<ProcessResult> {
    return new Promise((resolve, reject) => {
      const proc = spawn(this.pythonExe, [this.scriptPath], {
        stdio: ['pipe', 'pipe', 'pipe'],
      })

      // Send input as a single JSON line on stdin
      proc.stdin.write(JSON.stringify({
        input,
        params,
        nodeId:       input.nodeId ?? '',
        workspaceDir: this.workspaceDir,
        tempDir:      this.tempDir,
      }) + '\n')
      proc.stdin.end()

      let stdoutBuf = ''
      let resolved  = false

      proc.stdout.on('data', (chunk: Buffer) => {
        stdoutBuf += chunk.toString()
        const lines = stdoutBuf.split('\n')
        stdoutBuf = lines.pop() ?? ''

        for (const line of lines) {
          const trimmed = line.trim()
          if (!trimmed) continue
          try {
            const msg = JSON.parse(trimmed) as { type: string; percent?: number; label?: string; message?: string; result?: ProcessResult }
            if (msg.type === 'progress') {
              onProgress?.(msg.percent ?? 0, msg.label ?? '')
            } else if (msg.type === 'log') {
              onLog?.(msg.message ?? '')
            } else if (msg.type === 'done') {
              resolved = true
              resolve(msg.result ?? {})
            } else if (msg.type === 'error') {
              resolved = true
              reject(new Error(msg.message ?? 'Unknown error'))
            }