git-hours.py

#!/usr/bin/env python3
#
# Copyright (c) 2015 Leandro Pereira de Lima e Silva
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.
#

##
# Tip: consider putting this script on your path with the name git-hours; this
# way, you'll be able to invoke it as a git command (git hours)
##

import os, subprocess, codecs
from datetime import datetime, timedelta
from collections import namedtuple
from argparse import ArgumentParser

Commit = namedtuple('Commit', ['hash', 'merge', 'author', 'date', 'message',
                               'files', 'changes', 'insertions', 'deletions'])

def gitlog(author = None, since = None, until = None, files = []):
    '''Reads and parses git log yielding commits'''
    cmdline = ['/usr/bin/env', 'git', 'log', '--date=iso', '--shortstat']

    if author is not None:
        cmdline.append('--author=%s' % author)

    if since is not None:
        cmdline.append('--since=%s' % since.strftime('%Y-%m-%d %H:%M:%S %z'))

    if until is not None:
        cmdline.append('--until=%s' % until.strftime('%Y-%m-%d %H:%M:%S %z'))

    if len(files) > 0:
        cmdline.extend(files)

    reader = codecs.getreader('utf-8')
    gitlog = subprocess.Popen(cmdline, stdout = subprocess.PIPE)

    chash = None
    for line in reader(gitlog.stdout):
        line = line.rstrip()

        if line == '':
            continue

        # Detect message
        if line[:4] ==  '    ':
            message += line[4:]
            continue

        # Detect other fields
        splitline = line.split(' ', maxsplit = 1)
        if splitline[0] == 'commit':
            if chash is not None:
                yield Commit(chash, merge, author, date, message, files,
                             changes, insertions, deletions)
            chash = splitline[1]
            merge, author, date, message = False, None, None, ''
            files, changes, insertions, deletions = 0, 0, 0, 0
            continue
        if splitline[0] == 'Author:':
            author = splitline[1].strip()
            continue
        if splitline[0] == 'Date:':
            date = datetime.strptime(splitline[1].strip(), '%Y-%m-%d %H:%M:%S %z')
            continue
        if splitline[0] == 'Merge:':
            merge = True
            continue

        # Detect change statistics
        filesplit = line.lstrip().split(' ')
        if len(filesplit) >= 3 and filesplit[2] == 'changed,' and filesplit[1] in ('file', 'files'):
            files = int(filesplit[0], 10)
            if len(filesplit) == 5:
                if filesplit[4] in ('insertions(+)', 'insertion(+)'):
                    insertions = int(filesplit[3], 10)
                    changes = insertions
                elif filesplit[4] in ('deletions(-)', 'deletion(-)'):
                    deletions = int(filesplit[3], 10)
                    changes = deletions
                else:
                    print(filesplit[4])
            elif len(filesplit) == 7:
                insertions = int(filesplit[3], 10)
                deletions = int(filesplit[5], 10)
                changes = insertions + deletions

    if chash is not None:
        yield Commit(chash, merge, author, date, message, files,
                     changes, insertions, deletions)

def logpairs(options):
    '''Yields pairs of commits'''
    logiter = gitlog(**options)
    b = next(logiter)
    while True:
        try:
            a, b = b, next(logiter)
            yield a, b
        except StopIteration:
            return

def workinghours(maxidle = 2, **options):
    '''Estimate number of hours worked on a git repo'''
    maxidlehours = timedelta(hours = maxidle)
    days = set()
    known_hours = 0
    known_commits = 0
    known_changes = 0
    total_changes = 0
    commits = 1

    for a, b in logpairs(options):
        if a.merge or b.merge:
            continue

        days.add(a.date.date())
        commits += 1
        total_changes += a.changes

        if a.author != b.author:
            continue

        if b.date > a.date:
            continue

        timediff = a.date - b.date
        if timediff > maxidlehours:
            continue

        known_commits += 1
        known_hours += timediff.total_seconds() / 3600
        known_changes += a.changes


    try:
        hours = (known_hours / known_changes) * total_changes
    except ZeroDivisionError:
        return None

    return total_changes, commits, hours, len(days)

def parse_date(datestr):
    '''Parse dates accepted by --since and --until'''
    formats = ['%Y-%m-%d %H:%M:%S %z', '%Y-%m-%d %z',
               '%Y-%m-%d %H:%M:%S', '%Y-%m-%d']
    for f in formats:
        try:
            return datetime.strptime(datestr, f)
        except ValueError:
            continue
    return None

def parse_options():
    '''Parse command line options'''
    parser = ArgumentParser()
    parser.add_argument('-a', '--author', dest = 'author', metavar = 'name',
        help = 'Limit the computation to commits with author/committer header '
               'lines that match the specified pattern (regular expression).')
    parser.add_argument('-f', '--files',
        dest = 'files', metavar = 'file', nargs ='+', default = [],
        help = 'Limit the computation to commits that affected this '
               'file(s) or folder(s).')
    parser.add_argument('-i', '--maxidle',
        dest = 'maxidle', metavar = 'hours', type = float, default = 2,
        help = 'Maximum number of hours between commits before assuming '
               'that the programmer took a break (default: 2 hours).')
    parser.add_argument('-s', '--since', dest = 'since', metavar = 'date',
        help = 'Limit the computation to commits more recent than a specific '
               'date. Format: YYYY-MM-DD [HH:MM:SS] [[+-]ZZZZ].')
    parser.add_argument('-u', '--until', dest = 'until', metavar = 'date',
        help = 'Limit the computation to commits older than a specific date. '
               'Format: YYYY-MM-DD [HH:MM:SS] [[+-]ZZZZ].')
    args = parser.parse_args()

    ret = {}
    if args.author is not None:
        ret['author'] = args.author

    if args.since is not None:
        since = parse_date(args.since)
        if since is None:
            parser.error('Wrong date format for -s, --since.')
        ret['since'] = since

    if args.until is not None:
        until = parse_date(args.until)
        if until is None:
            parser.error('Wrong date format for -u, --until.')
        if len(args.until) < 11:
            until += timedelta(seconds = 86399)
        ret['until'] = until

    if len(args.files) > 0:
        for filename in args.files:
            try:
                os.stat(filename)
            except FileNotFoundError:
                parser.error('File or folder "%s" does not exist.' % filename)
        ret['files'] = args.files

    if args.maxidle is not None:
        ret['maxidle'] = args.maxidle

    return ret


if __name__ == '__main__':
    options = parse_options()
    gitstats = workinghours(**options)
    if gitstats is not None:
        print('Changes: %d / Commits: %s / Hours: %.0f / Days: %d' % gitstats)
    else:
        print('Not enough information to estimate working hours.')