[英]Python: initiated Logger with dataclass field param
这是我的Logger
class:
import logging
import os
import datetime
class Logger:
_logger = None
def __new__(cls, user: str, *args, **kwargs):
if cls._logger is None:
cls._logger = super().__new__(cls, *args, **kwargs)
cls._logger = logging.getLogger("crumbs")
cls._logger.setLevel(logging.DEBUG)
formatter = logging.Formatter('[%(asctime)s] [%(levelname)s] [%(filename)s] [%(funcName)s] [%(lineno)d]: %(message)s')
now = datetime.datetime.now()
directory_name = f'./log/{now.strftime("%Y-%m-%d")}'
base_log_name = f'/{user}'
log_file_extension = '.log'
if not os.path.isdir(directory_name):
os.mkdir(directory_name)
file_handler = logging.FileHandler(f'{directory_name}{base_log_name}{now.strftime("%d-%m-%Y")}{log_file_extension}', 'w', 'utf-8')
stream_handler = logging.StreamHandler()
file_handler.setFormatter(formatter)
stream_handler.setFormatter(formatter)
cls._logger.addHandler(file_handler)
cls._logger.addHandler(stream_handler)
return cls._logger
这是我的class
接受用户argument
,我希望我的log
文件在file name
中使用我的用户名创建:
@dataclass(kw_only=True)
class RunningJobManager:
user: str = field(init=True)
password: str = field(init=True)
logging: Logger = field(init=False, default_factory=Logger(user=user))
所以目前我在Logger
class 中的用户field
的类型是dataclasses.Field
而不是string
。 我也尝试使用default_factory
的default
instread
我得到了这个错误:
Curerenly 我的代码因 OSError,[Errno 22] 无效参数而崩溃:'G:\my_project\log\2023-01-20\Field(name=None,type=None,default=<dataclasses._MISSING_TYPE object at 0x0000017B1E78DB10>,default_factory = <dataclasses._missing_type object at 0x0000017b1e78db110>,init = true,repr = true,repr = note,sumh = none,compare = true,metadata = metadata = mappingproxy(} -01-2023.log'
在这一行:
file_handler = logging.FileHandler(f'{directory_name}{base_log_name}{now.strftime("%d-%m-%Y")}{log_file_extension}', 'w', 'utf-8')
这不是数据类根据其他字段处理字段初始化的方式。 field
的default_factory
参数应该是一个零参数的 callable 。 标准库文档指出:
default_factory:如果提供,它必须是一个零参数可调用函数,当此字段需要默认值时将被调用...
换句话说,不可能将任何参数传递给default_factory
。
使用其他字段的值初始化字段的正确方法是使用__post_install__
方法:
@dataclass(kw_only=True)
class RunningJobManager:
user: str = field(init=True)
password: str = field(init=True)
logging: Logger = field(init=False, default=None)
def __post_init__(self):
if self.logging is None:
self.logging = Logger(self.user)
这是dictConfig
的示例:
import logging
import os
from dataclasses import dataclass, field
from logging import Logger
from logging.config import dictConfig
@dataclass(kw_only=True)
class AbstractJobManager:
user: str = field(init=True)
@property
def logger(self) -> Logger:
return logging.getLogger('crumbs')
def __post_init__(self):
if not os.path.isdir('log'):
os.mkdir('log')
# some config from YAML, TOML or hardcoded - doesn't matter...
config = {
'version': 1,
'loggers': {
'crumbs': {
'level': 'INFO',
'handlers': ['file_handler'],
},
},
'handlers': {
'file_handler': {
'level': 'INFO',
'class': 'logging.handlers.RotatingFileHandler',
'filename': f'./log/{self.user}.log', # I skipped %Y-%m-%d...
'backupCount': 3,
'formatter': 'simple',
},
},
'formatters': {
'simple': {
'format': '%(pathname)s:%(lineno)d %(asctime)s - %(levelname)s - %(message)s',
},
},
}
dictConfig(config)
@dataclass(kw_only=True)
class RunningJobManager(AbstractJobManager):
password: str = field(init=True)
def run(self):
self.logger.info('user = %s, password = %s', self.user, self.password)
RunningJobManager(user='falukky', password='Hello World!').run()
RunningJobManager(user='ridley', password='scott').run()
RunningJobManager(user='jimi', password='hendrix').run()
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