Python 日志输出

### 示例
```
import logging

LOGFILE_PATH = "/var/log/app.log"
DATETIME_FORMAT = "%Y-%m-%d %H:%M:%S"
LOG_FORMAT = "%(levelname)s | %(asctime)s | %(filename)s:%(lineno)s | %(message)s"

# 创建格式化器 formatter
formatter = logging.Formatter(
    fmt=LOG_FORMAT,
    datefmt=DATETIME_FORMAT,
)

# 创建处理器 handler
stream_handler = logging.StreamHandler()
file_handler = logging.FileHandler(
    filename=LOGFILE_PATH,
    encoding="utf8",
)
file_handler.setFormatter(fmt=formatter)
stream_handler.setFormatter(fmt=formatter)

# 创建记录器 logger
logger = logging.getLogger(name="app")
# 同时往文件和控制台输出日志
logger.addHandler(file_handler)
logger.addHandler(stream_handler)
logger.setLevel(level=logging.DEBUG)

if __name__ == "__main__":
    logger.info("Hello !")
```
### 打印捕获的异常
打印捕获的异常，并打印出堆栈信息
```
a = "abc"
try:
	a = int(a)
except Exception as e:
	logger.exception(e)
```
输出为：
```
ERROR | 2021-08-26 17:01:59 | log.py:35 | invalid literal for int() with base 10: 'abc'
Traceback (most recent call last):
  File "/home/gaojian/code/benniao-backend/log/log.py", line 33, in <module>
    a = int(a)
ValueError: invalid literal for int() with base 10: 'abc'
```