logger.py

from datetime import datetime
from time import strftime

class Logger(list):
    '''
    This is a class to manage logging both to files and the console.
    It inherits from list so you can use append() to add entries to the buffer.
    Inputs:
        target - The filename to which the buffer will be written.
                 Specify this if you plan to use the write_out() method.
        timestamp - Booleam to enable prefixing entries with a timestamp.
                    Defaults to False.
    Methods:
    console_out() - Write the current buffer to the running shell.
    write_out() - Write the current buffer to the target specified.
                  This will fail with an error to the console if the target is missing.
    '''
    def __init__(self, target=None, timestamp=False):
        self._target = target
        self._timestamp = timestamp
        list.__init__(self)


    def append(self, item):
        if self._timestamp:
            timestr = datetime.now().strftime("%Y%m%d %H:%M:%S ")
            item = timestr + item
        super().append(item)


    def console_out(self):
        for entry in self:
            if isinstance(entry, list):
                for line in entry:
                    print(line)
            else:
                print(entry)


    def flush(self):
        self[:] = []


    def write_out(self):
        if self._target:
            with open(self._target, 'a') as f:
                for entry in self:
                    #output = entry
                    if isinstance(entry, list):
                        for line in entry:
                            output = '\n'.join([x for x in entry])
                    if isinstance(entry, str):
                        output = entry.rstrip() + '\n'
                    f.write(output)
        else:
            print('Cannot write output logs - no target specified.')