python--日志&异常处理

import pymysql
import nnlog
import traceback
示例一：
l = [ 1,2,3]
d = {}

try:
 # print(l[4])
 print(d['name'])
except Exception as e:
 print("出异常了",e)
else:
 print("不出异常的时候走到这里")
finally:
 print("什么时候走这里呢")
except IndexError as e:
 print("下标不存在")
 print(e)
except KeyError as e:
 print("key不存在")
 print(e)

示例二：
import pymysql
import nnlog
import traceback
log = nnlog.Logger('python.log',level='debug',backCount=5,when='D')##默认是debug级别最低的,默认保留5天的backCount when=‘D‘,# D H M S D=天，H=小时，M=分钟 S=秒
mysql_info = {
 'host':'...',
 'port':3306,
 'db':'XXX',
 'password':'123456',
 'charset':'utf8',
 'autocommit':True,
 'user':'jxz'
}
def op_db(sql,one_tag=True):
 try:
 log.debug("开始连接数据库，数据库连接信息是%s"%mysql_info)
 connect = pymysql.connect(**mysql_info)
 except Exception as e:
 log.debug("连接数据失败")
 log.error("连接数据失败,请检查")
 log.error(traceback.format_exc())
 # traceback.format_exc()拿到出错的那一大坨字符串
 #traceback.print_exc()#只print错误信息
 return "001"
 else:
 log.debug("开始建立游标")
 cur = connect.cursor(pymysql.cursors.DictCursor)
 try:
 log.debug("开始执行sql")
 log.info("sql语句是%s"%sql)
 cur.execute(sql)
 except Exception as e:
 log.warning("sql错误！")
 return "002"
 else:
 if one_tag:
 result = cur.fetchone()
 else:
 result = cur.fetchall()
 finally:
 cur.close()
 connect.close()
 return result