logging module
As the name implies, it is used for program log output. You can set the log level, format, output method, etc. The basic usage is as follows:
1、logging.basicConfig方式
Simple configuration, you can only choose to output to the screen or output to a file, but not at the same time. E.g:
#-*- coding:utf-8 -*-
#Can only choose to output to screen or file
import logging
logging.basicConfig(level=logging.DEBUG,
format='%(asctime)s %(filename)s[line:%(lineno)d] %(levelname)s %(message)s',
datefmt='%a,%d %b %Y %H:%M:%S',
filename='test.log',
filemode='a')
'''
parameter:
level: specifies the log level of the output
format: Specifies the log format, including:
asctime: time
filename: The name of the file to which the log belongs
lineno: the line number of the log corresponding code in the attribution file
levelname: day to the lowest level, if not specified, the default is warning
message: the specific log content,
datefmt: Specify a specific time format, if not specified, asctime will use the default format, such as: 2018-05-05 22:07:30,578
filename: specifies the name of the log file, which can carry a specific path. If this parameter is not specified, the log is output to the screen
filemode: specifies the log writing mode, the default is 'a' for appending, and it can be specified as 'w' for overwriting
'''
logging.debug('debug message')
logging.info('info message')
logging.warning('warning message')
logging.error('error message')
logging.critical('critical message')
The above example outputs the log to the test.log file, the content:
Sat,05 May 2018 22:25:14 2.py[line:22] DEBUG debug message Sat,05 May 2018 22:25:14 2.py[line:23] INFO info message Sat,05 May 2018 22:25:14 2.py[line:24] WARNING warning message Sat,05 May 2018 22:25:14 2.py[line:25] ERROR error message Sat,05 May 2018 22:25:14 2.py[line:26] CRITICAL critical message
If you only need to output the log to the screen, you only need to comment out the lines filename='test.log' and filemode='a'.
2. logging.getLogger method
Complete configuration, you can output to screen or file individually or simultaneously. E.g:
#-*- coding:utf-8 -*-
#Log output is more flexible and can be output to the screen and file separately or at the same time
import logging
#Create a logger object
logger=logging.getLogger()
#Create a file output stream handler for writing to the log file
fm=logging.FileHandler('test1.log')
#Create another standard output stream handler for output to the screen
pm=logging.StreamHandler()
#Create a log format object
formatter=logging.Formatter('%(asctime)s %(filename)s[line:%(lineno)d] %(levelname)s %(message)s')
#Add log format for two handlers
fm.setFormatter(formatter)
pm.setFormatter(formatter)
#Add handler for logger object
logger.addHandler(fm)
logger.addHandler(pm)
#Set the output log level, by default only output above warning
logger.setLevel(logging.DEBUG)
logger.debug('debug message')
logger.info('info message')
logger.warning('warning message')
logger.error('error message')
logger.critical('critical message')
In the above example, the log is output to the screen and the test1.log file at the same time, the content:
2018-05-05 22:32:52,800 3.py[line:28] DEBUG debug message 2018-05-05 22:32:52,800 3.py[line:29] INFO info message 2018-05-05 22:32:52,800 3.py[line:30] WARNING warning message 2018-05-05 22:32:52,800 3.py[line:31] ERROR error message 2018-05-05 22:32:52,800 3.py[line:32] CRITICAL critical message
logger.addHandler() determines the direction of log output. If it is only output to one side, you can comment out another line.
3. Specific application
#!/usr/local/python-3.4/bin/python3.4
#-*- coding:utf-8 -*-
import urllib.request
import time
import logging
#Here is used to request a url and return the status code
my_url='http://172.16.1.20:8080/bizmon/BIZServlet?BizCode=DX0001&BatchId=%s' %(int(time.time()))
def url_request():
url_response=urllib.request.urlopen(my_url)
url_code=url_response.code
return url_code
#define your own log function
def get_log():
logger=logging.getLogger()
fh=logging.FileHandler('test.log')
ph=logging.StreamHandler()
formatter=logging.Formatter('%(asctime)s %(filename)s[line:%(lineno)d] %(levelname)s %(message)s')
fh.setFormatter(formatter)
logger.addHandler(fh)
# logger.addHandler(ph)
logger.setLevel(logging.INFO)
return logger
if __name__ == "__main__":
my_log=get_log()
try:
code=url_request()
except Exception:
my_log.error("%s request failed!"%(my_url),exc_info=True) #Capture the exception and output it to the log
else:
my_log.info("%s request successful! code is %s"%(my_url,code)) #正常日志
Log content:
2018-05-07 19:41:41,575 16.py[line:28] ERROR http://172.16.1.20:8080/bizmon/BIZServlet?BizCode=DX0001&BatchId=1525693301 request failed! Traceback (most recent call last): File "C:/Users/Administrator/PycharmProjects/first/16.py", line 26, in <module> code=url_request() File "C:/Users/Administrator/PycharmProjects/first/16.py", line 8, in url_request url_response=urllib.request.urlopen(my_url) File "C:\Python3.6\lib\urllib\request.py", line 223, in urlopen return opener.open(url, data, timeout) File "C:\Python3.6\lib\urllib\request.py", line 532, in open response = meth(req, response) File "C:\Python3.6\lib\urllib\request.py", line 642, in http_response 'http', request, response, code, msg, hdrs) File "C:\Python3.6\lib\urllib\request.py", line 570, in error return self._call_chain(*args) File "C:\Python3.6\lib\urllib\request.py", line 504, in _call_chain result = func(*args) File "C:\Python3.6\lib\urllib\request.py", line 650, in http_error_default raise HTTPError(req.full_url, code, msg, hdrs, fp) urllib.error.HTTPError: HTTP Error 500: Internal Server Error
When catching an exception,
my_log.error("%s request failed!"%(my_url),exc_info=True)也可写成：my_log.exception("%s request failed!"%(my_url))