Python logging按级别拆分日志文件自定义Filter配置报错如何解决

报错本质是两个常见问题：Python模块搜索路径未包含src目录，或YAML过滤器配置格式错误，按以下步骤修改即可：

在调用logging.config.dictConfig加载YAML配置前，先把项目根目录和src目录加入sys.path，否则Python无法识别src.logger模块，参考代码：

import sys
from pathlib import Path
import yaml
import logging.config

# 自行调整路径层级，确保PROJECT_ROOT是src和resources文件夹的父目录
PROJECT_ROOT = Path(__file__).parent.parent
sys.path.append(str(PROJECT_ROOT))
sys.path.append(str(PROJECT_ROOT / "src"))

# 路径配置完成后再加载日志配置
with open(PROJECT_ROOT / "resources" / "log.yaml", "r", encoding="utf-8") as f:
    log_config = yaml.safe_load(f)
logging.config.dictConfig(log_config)

不需要加ext://前缀，用()特殊键标识自定义类即可，完整配置片段参考：

version: 1
disable_existing_loggers: False

# 过滤器配置段
filters:
  info_filter:
    '()': src.logger.InfoFilter
  warning_filter:
    '()': src.logger.WarningFilter
  error_filter:
    '()': src.logger.ErrorFilter
  critical_filter:
    '()': src.logger.CriticalFilter

# handler关联过滤器示例
handlers:
  info_file:
    class: logging.handlers.RotatingFileHandler
    level: INFO
    filters: [info_filter]
    filename: logs/info.log
    maxBytes: 10485760
    backupCount: 10
    encoding: utf-8
    formatter: standard
  warning_file:
    class: logging.handlers.RotatingFileHandler
    level: WARNING
    filters: [warning_filter]
    filename: logs/warning.log
    maxBytes: 10485760
    backupCount: 10
    encoding: utf-8
    formatter: standard
# 其余handler、formatter、root配置按原有逻辑正常编写即可

src/logger.py中的过滤器必须继承logging.Filter，且定义在模块顶层，不要写在if __name__ == "__main__"块中，参考写法：

import logging

class InfoFilter(logging.Filter):
    def filter(self, record):
        return record.levelno == logging.INFO

class WarningFilter(logging.Filter):
    def filter(self, record):
        return record.levelno == logging.WARNING

class ErrorFilter(logging.Filter):
    def filter(self, record):
        return record.levelno == logging.ERROR

class CriticalFilter(logging.Filter):
    def filter(self, record):
        return record.levelno == logging.CRITICAL

如果仍报错，可在加载日志配置前先执行import src.logger，如果导包报错优先解决路径问题，再加载日志配置即可。

内容的提问来源于stack exchange，提问作者MinionAttack