Progress-reporting line reader

progress.py

import os
 
 
class ProgressLineReader(object):
    def __init__(self, filepath, mode='r'):
        self.path = filepath
        self.total_size = os.stat(filepath).st_size
        self.already_read = 0
        self.fobj = open(filepath, mode)
 
    def __iter__(self):
        for line in self.fobj:
            self.already_read += len(line)
            yield line
     
    def __enter__(self):
        return self

    def __exit__(self, exc_type, exc_value, traceback):
        self.close()

    @property
    def progress(self):
        """Percentage read"""
        return 100.0 * self.total_size / self.already_read

    def close(self):
        self.fobj.close()

usage.py

import csv

from progress import ProgressLineReader


with ProgressLineReader('path/to/file.csv') as progressreader:
    for row in csv.reader(progressreader):
        print 'Got row: {0}'.format(row)
        print 'Read {0.already_read} of {0.total_size}, {0.progress} %'.format(progressreader)