PyYAML读取含!vault标签的YAML文件时找不到构造器如何解决？

PyYAML的SafeLoader默认没有内置Ansible自定义的!vault标签构造器，遇到该标签时无法完成解析，因此抛出对应报错。

根据是否需要解密!vault对应密文，可选择以下两种实现方式：

场景1：无需解密!vault内容，仅读取其他明文字段 #

只需给SafeLoader注册自定义的!vault标签构造器，直接将标签后的密文内容作为字符串返回即可，修改后代码如下：

import yaml
from yaml.loader import SafeLoader

# 自定义!vault标签的构造器
def vault_constructor(loader, node):
    # 直接返回!vault后面的密文字符串
    return loader.construct_scalar(node)

# 给SafeLoader注册!vault标签的构造器
yaml.add_constructor('!vault', vault_constructor, Loader=SafeLoader)

with open('test.yml' ) as stream:
    try:
        inventory_info = yaml.safe_load(stream)
    except yaml.YAMLError as exc:
        print(exc)

User = inventory_info['all']['children']['linux']['vars']['user']
key = inventory_info['all']['children']['linux']['vars']['key_file']
# 也可直接获取vault对应的密文字符串
vault_pwd = inventory_info['all']['children']['linux']['vars']['ansible_password']

场景2：需要解密!vault内容获取明文密码 #

如果需要直接解析出明文密码，需要借助Ansible官方库实现解密操作，首先安装依赖：
pip install ansible
对应实现代码如下：

from ansible.parsing.vault import VaultLib, VaultSecret
from ansible.module_utils.common.text.converters import to_bytes
import yaml
from yaml.loader import SafeLoader

# 替换为加密该vault字段时使用的密码
VAULT_PASSWORD = "你的vault解密密码"

def vault_constructor(loader, node):
    vault_text = loader.construct_scalar(node)
    # 初始化vault解密工具
    vault = VaultLib(secrets=[('default', VaultSecret(_bytes=to_bytes(VAULT_PASSWORD)))])
    # 解密返回明文
    return vault.decrypt(vault_text)

yaml.add_constructor('!vault', vault_constructor, Loader=SafeLoader)

with open('test.yml' ) as stream:
    try:
        inventory_info = yaml.safe_load(stream)
    except yaml.YAMLError as exc:
        print(exc)

User = inventory_info['all']['children']['linux']['vars']['user']
key = inventory_info['all']['children']['linux']['vars']['key_file']
# 此时获取到的就是解密后的明文密码
plain_pwd = inventory_info['all']['children']['linux']['vars']['ansible_password']

内容的提问来源于stack exchange，提问作者Eva