Method spawnProcess

packages/ai-sandbox-vercel/src/handle.ts:225–286

(
    command: string,
    opts?: ProcessOptions,
  )

  }

  private async spawnProcess(
    command: string,
    opts?: ProcessOptions,
  ): Promise<SpawnHandle> {
    const controller = new AbortController()
    if (opts?.signal) {
      opts.signal.addEventListener('abort', () => controller.abort(), {
        once: true,
      })
    }

    const cmd: Command = await this.sandbox.runCommand({
      cmd: 'sh',
      args: ['-c', command],
      cwd: opts?.cwd ? this.abs(opts.cwd) : this.workdir,
      env: this.mergedEnv(opts?.env),
      detached: true,
      signal: controller.signal,
    })

    const stdoutQ = new AsyncChunkQueue()
    const stderrQ = new AsyncChunkQueue()

    // Fan the single interleaved log stream out into stdout/stderr iterables.
    const pump = (async (): Promise<void> => {
      try {
        for await (const log of cmd.logs()) {
          if (log.stream === 'stderr') stderrQ.push(log.data)
          else stdoutQ.push(log.data)
        }
      } catch {
        // Stream torn down (kill/abort) — fall through and close the queues.
      } finally {
        stdoutQ.end()
        stderrQ.end()
      }
    })()

    return {
      pid: -1, // Vercel commands do not surface a host-visible pid.
      stdout: stdoutQ,
      stderr: stderrQ,
      stdin: {
        write: () =>
          Promise.reject(
            new Error(
              'vercel: background process stdin is not writable (see capabilities.writableStdin)',
            ),
          ),
        end: () => Promise.resolve(),
      },
      wait: async () => {
        const finished = await cmd.wait()
        await pump
        return finished.exitCode
      },
      kill: () => {
        controller.abort()