Ubuntu22.04下Flask调用Playwright脚本报错：Connection closed while reading from the driver

可能的原因及排查步骤 #

1. 权限问题（最常见） #

直接运行脚本用的是当前用户，但Nginx/Flask通常以www-data用户运行，该用户可能没有Playwright浏览器或驱动的访问权限：

• 测试www-data能否运行Playwright基础代码：

  sudo -u www-data python3 -c "from playwright.sync_api import sync_playwright; p=sync_playwright().start(); p.stop()"
  

  如果报错，说明权限不足，执行以下命令给www-data安装专属的Playwright浏览器：

  sudo -u www-data playwright install
  

2. 环境变量/路径不匹配 #

直接执行脚本时的环境变量和Flask运行时的不一致，导致找不到Playwright资源：

• 在Flask代码中手动指定浏览器安装路径：

  from playwright.sync_api import sync_playwright
  import os
  
  def run_script():
      # 替换成你当前用户下的Playwright浏览器缓存路径，可通过`playwright install --help`查看默认路径
      os.environ["PLAYWRIGHT_BROWSERS_PATH"] = "/home/your_username/.cache/ms-playwright"
      playwright = sync_playwright().start()
      # 后续业务代码...
      playwright.stop()
  

• 或者在Flask启动脚本中同步环境变量，确保和直接执行时一致。

3. 系统资源限制不足 #

www-data用户的文件描述符或内存限制过低，导致Playwright启动失败：

• 修改系统限制，编辑/etc/security/limits.conf，添加：

  www-data soft nofile 65535
  www-data hard nofile 65535
  

• 重启Nginx和Flask服务生效：

  sudo systemctl restart nginx
  sudo systemctl restart your_flask_service
  

替代方案 #

异步任务队列（推荐） #

用Celery将Playwright任务剥离到独立worker执行，避免Flask进程阻塞：

1. 安装Celery和消息中间件（比如Redis）
2. 定义Celery任务：

   # tasks.py
   from celery import Celery
   from playwright.sync_api import sync_playwright
   
   celery = Celery('tasks', broker='redis://localhost:6379/0')
   
   @celery.task
   def run_playwright_task():
       playwright = sync_playwright().start()
       # 业务代码...
       playwright.stop()
       return "任务完成"
   

3. Flask路由中提交任务：

   from flask import Flask
   from tasks import run_playwright_task
   
   app = Flask(__name__)
   
   @app.route('/trigger-task')
   def trigger():
       task = run_playwright_task.delay()
       return f"任务已提交，ID: {task.id}"
   

异步Playwright+Flask异步路由 #

Flask 2.0+支持异步路由，配合Playwright异步API：

from flask import Flask
from playwright.async_api import async_playwright

app = Flask(__name__)

@app.route('/run-playwright')
async def run_playwright():
    async with async_playwright() as p:
        browser = await p.chromium.launch()
        page = await browser.new_page()
        await page.goto("https://example.com")
        # 业务操作...
        await browser.close()
        return "执行成功"

内容的提问来源于stack exchange，提问作者Suren Gunaseelan