Making Python loggers log all stdout and stderr messages

The right way to achieve what you ask is to use Logger object. It gives you much more flexability. This object can be bound to multiple handlers; You need a streamhandler to log message to sys.stdout and a file handler to log it to a file. You then both print to the screen and log to a file in a single command.

import logging # create logger logger = logging.getLogger('example') logger.setLevel(logging.INFO) # create file handler which logs messages fh = logging.FileHandler('fh.log') fh.setLevel(logging.DEBUG) # create console handler to print to screen ch = logging.StreamHandler() ch.setLevel(logging.INFO) # create formatter and add it to the handlers formatter = logging.Formatter('%(asctime)s - %(name)s - %(levelname)s - %(message)s') fh.setFormatter(formatter) ch.setFormatter(formatter) # add the handlers to the logger logger.addHandler(fh) logger.addHandler(ch) 

Now every call to logger.info(msg) will be printed both to the screen, and written to fh.log file.

There is another way, where you can replace sys.stdout and sys.stderr stream objects. Create a class and customize it (original answer here):

import sys class writer(object): _fh = None _orig_stdout = sys.stdout def __init__(self): _fh = open('logging.log', 'w') def write(self, data): fp.write(data) _orig_stdout.write(data) def flush(): _orig_stdout.flush() logger = writer() sys.stdout = logger sys.stderr = logger 

I made this package to do exactly what you said.

pip install stdlogging 

After installed from pip, you can capture any output by logging. But be careful to capture stdout because it's very fragile.

import stdlogging stdlogging.enable(stdout=False, stderror=True)