flask:报错：RuntimeError: 'cryptography' package is required for sha256_password or caching_sha2_password auth methods

一，报错信息:

RuntimeError: 'cryptography' package is required for sha256_password or caching_sha2_password auth methods

 

二，解决:

原因是缺少cryptography库，导致建立到mysql的连接时出错

$ pip3 install cryptography

重启flask后恢复正常