Write log messages to the console (sys.stdout) and to a log file, all managed as a context manager.

logger.py

import sys


class Logger(object):
    """
    Write log messages to the console (sys.stdout) and to a log file,
    all managed as a context manager:

    >>> with Logger('log_file.txt'):
    ...   print "Hello, World!"  # goes to stdout and to the log file
    ...
    Hello, World!
    >>> print open('log_file.txt').read()
    Hello, World!
    """
    def write(self, message):
        self.console.write(message)
        self.console.flush()
        self.log_file.write(message)
        self.log_file.flush()

    def close(self):
        self.console.flush()
        self.log_file.flush()
        self.log_file.close()

    def __init__(self, log_file):
        self.console = sys.stdout
        self.log_file_name = log_file
        self.log_file = None

    def __enter__(self):
        self.log_file = open(self.log_file_name, 'w')
        sys.stdout = self
        return self

    def __exit__(self, *args):
        self.close()
        sys.stdout = self.console
        return not any(args)