Python logging delete log file

Python: can’t delete file after logging to

Is there any way can match the follow requests on the same time: create log file if file does not exist when app starts. (I know module has already do this for me) if log file is deleted after app starts, create log file again and continue logging without restart app.

Python: can’t delete file after logging to

I’m writing to log file using the following code:

import logging from gmplot import gmplot logging.basicConfig(filename="sample.log", level=logging.INFO) logging.debug("This is a debug message") logging.info("Informational message") logging.error("An error has happened!") 

But then it’s impossible to delete this file. how can I ‘release’ this file?

You need to close() your logging:

When your Run class completes, call:

handlers = self.log.handlers[:] for handler in handlers: handler.close() self.log.removeHandler(handler) 

simply use logging.shutdown(), when you are done with logging.

Logging — Automatically delete old Python log files, If the file is older than the current date by 3 months. Then delete it with. import os os.remove («filename.extension») save this file to py2exe, then just use any task scheduler to run this job at startup. Windows: open the run command and enter shell:startup, then place your exe in here. Code samplefrom logging import Formatterlogger = logging.getLogger(__name__)handler = TimedRotatingFileHandler(filename=’runtime.log’, when=’D’, interval=1, backupCount=90, encoding=’utf-8′, delay=False)formatter = Formatter(fmt=’%(asctime)s — %(name)s — %(levelname)s — %(message)s’)handler.setFormatter(formatter)Feedback

Logs are lost due to log rotation of logging module

I have written some devops related migration tool in python which runs for several hours (like 50-60 hours for each cluster migration activity). I used python’s logging module in the tool to log relevant information. The log automatically rotates every 24 hours. As a result, the old log file gets zipped into .gz format and a new empty file (with same name) gets created. However, in the new file I cannot find any logs (that I thought would contain logs after the log rotation)

I tried googling this problem, but couldn’t find relevant information. Would highly appreciate any help regarding this.

code snippet: import logging LOG = logging.getLogger( name )

def setup_logging(logfile, levelName): filename = logfile try: level = getattr(logging, levelName.upper()) except: print ‘Invalid loglevel:%s’ % levelName logging.basicConfig(filename=filename, level=level, format=’%(asctime)s [%(levelname)s] [%(filename)s:%(lineno)s — %(funcName)s()] %(message)s’)

After setting up logging like that I use something like:

Ok. So I found a way to handle this kind of scenario by using WatchedFileHandler as suggested here:

Python logging and rotating files, Since rotation is already being done by logrotate, in your signal handler you should just call logging.basicConfig () again and that should reopen the log file. basicConfig is a no-op if it’s already been run. To force it to reconfigure everything again, you have to set logging.root.handlers = [] first.

Python logging lost message after log file is deleted

I’m using RotatingFileHandler and TimedRotatingFileHandler . Everthing goes fine until I manually deleted the log file.
For example, my log file is wrote to /path/to/mylog.log . If this file got deleted or gzipped, python is not able to find it and all later log messages got lost, though all code may seem goes well.

Is there any way can match the follow requests on the same time:

• create log file if file does not exist when app starts. (I know logging module has already do this for me)
• if log file is deleted after app starts, create log file again and continue logging without restart app.
• logging rotating still works properly as what RotatingFileHandler and TimedRotatingFileHandler do.

Thank you for @blues ‘s answer. I tried his advice and got some code here, not fully tested, but it seems to work.

import logging from logging.handlers import RotatingFileHandler, WatchedFileHandler, TimedRotatingFileHandler class WatchedRotatingFileHandler(RotatingFileHandler, WatchedFileHandler): def __init__(self, filename, mode='a', maxBytes=0, backupCount=0, encoding=None, delay=False): RotatingFileHandler.__init__(self, filename=filename, mode='a', maxBytes=maxBytes, backupCount=backupCount, encoding=encoding, delay=delay) self.dev, self.ino = -1, -1 self._statstream() def emit(self, record): try: if self.shouldRollover(record): self.doRollover() # notice reopenIfNeeded() calls os.stat # may cause self.reopenIfNeeded() logging.FileHandler.emit(self, record) except Exception: self.handleError(record) class WatchedTimedRotatingFileHandler(TimedRotatingFileHandler, WatchedFileHandler): def __init__(self, filename, when='h', interval=1, backupCount=0, encoding=None, delay=False, utc=False, atTime=None): TimedRotatingFileHandler.__init__( self, filename, when=when, interval=interval, backupCount=backupCount, encoding=encoding, delay=delay, utc=utc, atTime=atTime ) self.dev, self.ino = -1, -1 self._statstream() def emit(self, record): try: if self.shouldRollover(record): self.doRollover() # notice that reopenIfNeeded calls os.stat # it may cause efficiency issues self.reopenIfNeeded() logging.FileHandler.emit(self, record) except Exception: self.handleError(record) 

You will have to write your own Logger class that does this. The FileHandlers assume that once the app has started that the file isn’t touched by anything outside the script.

There is a special handler for the case where the file can be deleted/moved while the app is running. It is the WatchedFileHandler and it’s a version of the FileHandler that will reopen/recreate the file if it is gone. There is however no version of this for the rotating handlers.

So you will have to combine the WatchedFileHandler and the RotatingFileHandler to get the functionality of both.

Python: can’t delete file after logging to, 2 Answers. Sorted by: 6. You need to close () your logging: As explained there: python does not release filehandles to logfile. When your Run class completes, call: handlers = self.log.handlers [:] for handler in handlers: handler.close () self.log.removeHandler (handler) Share. Improve this answer.

Forcing a log rotation in python logging module

If I have a rotating logging file. (logging_file.log) that rotates when x condition is met. How do I make it rotate? I know the rotating log module rotates automatically when the size exceeds a certain amount, but how do I make this rotation happen in the logging module for a different condition that is not size. Or how do I just force it to rotate the logging into a new logging file for whatever reason. Is there a function or command for this? Simply put how do I manually rotate a logging file if I want to use a newer and archive the old one. something like

if lines_in_file > 3 rotate() 

[note: the condition to make it rotate is irrelevant but I’m trying to ask for what function will make this rotation happen. Is there a simple function that does the job of rotate?

You should have (or can save) a reference to the appropriate instance of RotatingFileHandler from when you configured the logger. You just need to invoke its doRollover method:

rfh = RotatingFileHandler('foo.log') . rfh.doRollover() 

More generally, RotatingFileHandler.doRollover uses BaseRotatingHandler.rotate , which takes the source and destination file names. rotate either calls the handler’s rotator attribute with the same arguments, or just moves the source to the destination.

Python — Logs are lost due to log rotation of logging, I used python’s logging module in the tool to log relevant information. The log automatically rotates every 24 hours. As a result, the old log file gets zipped into .gz format and a new empty file (with same name) gets created. However, in the new file I cannot find any logs (that I thought would …

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logging in python to scroll logs and delete expired logs

The logging library provides two class es for log scrolling (refer to https://docs.python.org/2/library/logging.handlers.html), one is Rotating FileHandler, which scrolls mainly according to the size of the log file, and the other is TimeRotating FileHandler, which scrolls mainly according to time. In practical applications, we usually scroll according to time, so this article mainly introduces the use of TimeRotaingFileHandler (Rotating FileHandler is the same). The code example is as follows:

#!/usr/bin/env python #_*_coding:utf-8_*_ # vim : set expandtab ts=4 sw=4 sts=4 tw=100 : import logging import time import re from logging.handlers import TimedRotatingFileHandler from logging.handlers import RotatingFileHandler def main(): #Log Printing Format log_fmt = '%(asctime)s\tFile \"%(filename)s\",line %(lineno)s\t%(levelname)s: %(message)s' formatter = logging.Formatter(log_fmt) #Establish TimedRotatingFileHandler object log_file_handler = TimedRotatingFileHandler(filename="ds_update", when="M", interval=2, backupCount=2) #log_file_handler.suffix = "%Y-%m-%d_%H-%M.log" #log_file_handler.extMatch = re.compile(r"^\d-\d-\d_\d-\d.log$") log_file_handler.setFormatter(formatter) logging.basicConfig(level=logging.INFO) log = logging.getLogger() log.addHandler(log_file_handler) #Cyclic Printing Log log_content = "test log" count = 0 while count < 30: log.error(log_content) time.sleep(20) count = count + 1 log.removeHandler(log_file_handler) if __name__ == "__main__": main()

filename: prefix for log file name;
when: is a string used to describe the basic unit of the rolling cycle. The value and meaning of the string are as follows:
«S»: Seconds
«M»: Minutes
«H»: Hours
«D»: Days
«W»: Week day (0=Monday)
«midnight»: Roll over at midnight
Interval: Scroll cycle, when specified in units, such as: when=’D’, interval=1, which means that a log file is generated every day;
backupCount: Represents the number of log files retained;
In addition to the above parameters, Timed Rotating FileHandler has two more important member variables, suffix and extMatch, respectively. Suffix refers to the suffix of the log file name. Suffix usually has a formatted time string. Filename and suffix are connected by «. » to form the file name (e.g. filename = «runtime», suffix = «% Y-%m-%d.log», and the generated file is called runtime.2015-07-06.log). ExtMatch is a compiled regular expression that matches the suffix of the log file name. It must match suffix. If suffix and extMatch do not match, the expired log will not be deleted. For example, suffix = «% Y-%m-%d.log», extMatch should only be re.compile(r «^ D — d — d . log $»). By default, when the TimedRotatingFileHandler object is initialized, suffxi and extMatch initialize according to the value of when:

'S': suffix="%Y-%m-%d_%H-%M-%S", extMatch=r"\^d-\d-\d_\d-\d-\d>"； 'M':suffix="%Y-%m-%d_%H-%M",extMatch=r"^\d-\d-\d_\d-\d>"; 'H':suffix="%Y-%m-%d_%H",extMatch=r"^\d-\d-\d_\d>"; 'D':suffxi="%Y-%m-%d",extMatch=r"^\d-\d-\d>"; 'MIDNIGHT':"%Y-%m-%d",extMatch=r"^\d-\d-\d>"; 'W':"%Y-%m-%d",extMatch=r"^\d-\d-\d";

If there is no special requirement for log file names, you don’t need to set suffix and extMatch. If you need to, you must match them.

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