[python] yaml example

最新推荐文章于 2024-05-30 19:32:46 发布

原创最新推荐文章于 2024-05-30 19:32:46 发布 · 302 阅读

0 ·

CC 4.0 BY-SA版权

Python 专栏收录该内容

25 篇文章

订阅专栏

本文介绍了一个使用Python进行YAML文件读取、更新和写入的脚本。该脚本包括了加载YAML文件、更新用户信息和账户信息、以及将更新后的数据写回YAML文件的功能。通过使用fcntl模块来实现文件的锁定，确保了在同一时间只有一个进程能够修改文件，避免了数据冲突。

摘要生成于 C知道，由 DeepSeek-R1 满血版支持，前往体验 >

#!/usr/bin/env python3

import sys
import os
import re
import yaml
import pprint
import datetime
import fcntl

DEBUG_MODE = False
script_path = re.match('(,*)/.*',sys.argv[0]).group(1)
RECORDER_FILE = script_path + "/info.yaml"

def load_yaml(yaml_file):

    """ parsing yaml file """
    if(DEBUG_MODE): 
        print("YAML FILE(load):" + yaml_file)
    if(os.access(yaml_file,os.F_OK|os.R_OK)): # exist and readable
        yaml_f = open(yaml_file)
        fcntl.flock(yaml_f,fcnt.LOCK_EX) # lock file
        yaml_dir = yaml.load(yaml_f)
        fcntl.flock(yaml_f,fcnt.LOCK_UN) # unlock file
        yaml_f.close()
     else:
         print("ERROR:%s not exist or unreadable" % (yaml_file))
         yaml_dir = {}
         return yaml_dir

     if(yaml_dir is None):
         yaml_dir = {}
     return yaml_dir


def update_yaml(yaml_dir):
    """ update yaml file """
    if(DEBUG_MODE): pprint.pprint(yaml_dir)
    
    update_flag = False
    account  = os.popen("echo $USER").read().replace("\n",'')
    username = os.popen("echo $P4USER").read().replace("\n",'')
    hostname = os.popen("echo hostname").read().replace("\n",'')
    data     = datetime.datetime.now().strftime('%F %T')

    if(username not in yaml_dir):
        update_flag = True
        yaml_dir[username] = {}
        if(DEBUG_MODE): print("add new user: %s" %(username))
    else:
        if(account not in yaml_dir[username]):
            update_flag = True
             if(DEBUG_MODE): print("add new account: %s" %(account))
    if(update_flag):
        yaml_dir[username][account] = hostname
    
    if(DEBUG_MODE): pprint.pprint(yaml_dir)
    
    return update_flag,yaml_dir;


def dump_yaml(yaml_file,yaml_dir):

    """write yaml file"""
    if(DEBUG_MODE): print("YAML FILE(dump):" + yaml_file)

    if(os.access(yaml_file,os.F_OK|os.R_OK)): # exist and readable
        yaml_f = open(yaml_file,'w')
        fcntl.flock(yaml_f,fcnt.LOCK_EX) # lock file
        yaml.dump(yaml_dir,yaml_f,default_flow_style=False)
        fcntl.flock(yaml_f,fcnt.LOCK_UN) # unlock file
        yaml_f.close()
     else:
         return False
  
    if(DEBUG_MODE): print(result)
    return True


def main():
     yaml_dir_read = load_yaml(RECORDER_FILE)
     update_flag,yaml_dir_write = update_yaml(yaml_dir_read)
     if(update_flag):
         f_lock = open(RECORDER_FILE)//文件锁，保证同一时间只有一个进程在写此文件
         fcntl.flock(f_lock,fcntl.LOCK_EX)
         
         yaml_dir_read = load_yaml(RECORDER_FILE)
         update_flag,yaml_dir_write = update_yaml(yaml_dir_read)
         dump_yaml(RECORDER_FILE,yaml_dir_write)
 
         fcntl.flock(f_lock,fcntl.LOCK_UN)
         f_lock.close()

if __name__ == '__main__':

    main()