如何在pytest-parallel中获取类似pytest-xdist的worker_id及进程ID？

云原生阿岚

2026-7-12

解决pytest-parallel中获取进程ID及session级fixture缓存问题

1. 获取进程ID的方法

pytest-parallel未提供worker_id这类专属fixture，可直接通过Python标准库os模块获取当前进程ID：

import os

current_pid = os.getpid()

2. 适配pytest-parallel的session级WebDriver缓存fixture

针对pytest-parallel会忽略session作用域的问题，可通过文件锁+共享临时文件实现驱动缓存，同时用进程ID替代worker_id做进程标识：

import os
import json
from filelock import FileLock
import pytest
from your_module import SeleniumConfig, install_driver

@pytest.fixture(scope='session')
def driver_path_lock(selenium_config: SeleniumConfig, tmp_path_factory) -> str:
    """
    下载WebDriver并在session级别缓存，适配pytest-parallel
    """
    current_pid = os.getpid()
    # 获取所有并行进程共享的临时目录父级
    root_tmp_dir = tmp_path_factory.getbasetemp().parent
    fn = root_tmp_dir / "driver_cache.json"
    lock_fn = root_tmp_dir / "driver_cache.lock"

    with FileLock(str(lock_fn)):
        if fn.is_file():
            data = json.loads(fn.read_text())
            print(f"进程 {current_pid} 读取缓存的驱动路径")
        else:
            data = install_driver(selenium_config)
            fn.write_text(json.dumps(data))
            print(f"进程 {current_pid} 首次安装驱动并写入缓存")
    
    return data