Chart from git repo to show Drupal field changes over time

Drupal Fields Over Time

#!/usr/bin/env python
# -*- coding: utf-8 -*-
#
# Copyright (C) 2013-2015 Sébastien Helleu <flashcode@flashtux.org>
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

"""
Generate statistic charts for a git repository using pygal
(http://pygal.org).
"""

from __future__ import division, print_function

import argparse
import datetime
import os
import pygal
import re
import select
import subprocess
import sys
import traceback

VERSION = '1.3-dev'


# pylint: disable=too-few-public-methods,too-many-instance-attributes
class GitChart(object):
    """Generate a git stat chart."""

    # List of supported chart styles
    charts = {
        'fields': 'Drupal Field Changes',
    }

    months = [datetime.date(2001, month, 1).strftime('%b')
              for month in range(1, 13)]
    # Pygal style with transparent background and custom colors
    style = pygal.style.Style(
        background='transparent',
        plot_background='transparent',
        foreground='rgba(0, 0, 0, 0.9)',
        foreground_light='rgba(0, 0, 0, 0.6)',
        foreground_dark='rgba(0, 0, 0, 0.2)',
        opacity_hover='.4',
        colors=('#9999ff', '#8cedff', '#b6e354',
                '#feed6c', '#ff9966', '#ff0000',
                '#ff00cc', '#899ca1', '#bf4646')
    )

    # pylint: disable=too-many-arguments
    def __init__(self, chart_name, title=None, repository='.', output=None,
                 max_diff=20, sort_max=0, js='', in_data=None):
        self.chart_name = chart_name
        self.title = title if title is not None else self.charts[chart_name]
        self.repository = repository
        self.output = output
        self.max_diff = max_diff
        self.sort_max = sort_max
        self.javascript = js.split(',')
        self.in_data = in_data

    def _git_command(self, command1, command2=None):
        """
        Execute one or two piped git commands.

        Return the output lines as a list.
        """
        if command2:
            # pipe the two commands and return output
            proc1 = subprocess.Popen(command1, stdout=subprocess.PIPE,
                                     cwd=self.repository)
            proc2 = subprocess.Popen(command2, stdin=proc1.stdout,
                                     stdout=subprocess.PIPE,
                                     cwd=self.repository)
            proc1.stdout.close()
            return proc2.communicate()[0].decode('utf-8', errors='ignore') \
                .strip().split('\n')
        else:
            # execute a single git cmd and return output
            proc = subprocess.Popen(command1, stdout=subprocess.PIPE,
                                    cwd=self.repository)
            return proc.communicate()[0].decode('utf-8', errors='ignore') \
                .strip().split('\n')

    # pylint: disable=too-many-arguments
    def _generate_bar_chart(self, data, sorted_keys=None, max_keys=0,
                            max_x_labels=0, x_label_rotation=0):
        """Generate a bar chart."""
        bar_chart = pygal.Bar(style=self.style, show_legend=False,
                              x_label_rotation=x_label_rotation,
                              label_font_size=12, js=self.javascript)
        bar_chart.title = self.title
        # sort and keep max entries (if asked)
        if self.sort_max != 0:
            sorted_keys = sorted(data, key=data.get, reverse=self.sort_max < 0)
            keep = -1 * self.sort_max
            if keep > 0:
                sorted_keys = sorted_keys[:keep]
            else:
                sorted_keys = sorted_keys[keep:]
        elif not sorted_keys:
            sorted_keys = sorted(data)
        if max_keys != 0:
            sorted_keys = sorted_keys[-1 * max_keys:]
        bar_chart.x_labels = sorted_keys[:]
        if max_x_labels > 0 and len(bar_chart.x_labels) > max_x_labels:
            # reduce number of x labels for readability: keep only one label
            # on N, starting from the end
            num = max(2, (len(bar_chart.x_labels) // max_x_labels) * 2)
            count = 0
            for i in range(len(bar_chart.x_labels) - 1, -1, -1):
                if count % num != 0:
                    bar_chart.x_labels[i] = ''
                count += 1
        bar_chart.add('', [data[k] for k in sorted_keys])
        self._render(bar_chart)

    def _chart_fields(self):
        """Generate bar chart with field changes."""
        # format of lines in stdout: 2014-10-01
        stdout = self._git_command(['git', 'log', '--date=short',
                                    '--pretty=format:%ad', '--',
                                    '*/*.features.field_base.inc'])
        commits = {}
        for line in stdout:
            date = datetime.datetime.strptime(line, "%Y-%m-%d").date()
            year, week, weekday = date.isocalendar()
            commit_week = "{}-{}".format(year, week)
            commits[commit_week] = commits.get(commit_week, 0) + 1
        self._generate_bar_chart(commits, max_keys=self.max_diff,
                                 x_label_rotation=45)
        return True

    def _render(self, chart):
        """Render the chart in a file (or stdout)."""
        if self.output == '-':
            # display SVG on stdout
            print(chart.render())
        elif self.output.lower().endswith('.png'):
            # write PNG in file
            chart.render_to_png(self.output)
        else:
            # write SVG in file
            chart.render_to_file(self.output)

    def generate(self):
        """Generate a chart, and return True if OK, False if error."""
        try:
            # call method to build chart (name of method is dynamic)
            return getattr(self, '_chart_' + self.chart_name)()
        except Exception:
            traceback.print_exc()
            return False


def main():
    """Main function, entry point."""
    # parse command line arguments
    pygal_config = pygal.Config()
    parser = argparse.ArgumentParser(
        formatter_class=argparse.ArgumentDefaultsHelpFormatter,
        description='Generate statistic charts for a git repository.',
        epilog='Return value: 0 = success, 1 = error.')
    parser.add_argument(
        '-t', '--title',
        help='override the default chart title')
    parser.add_argument(
        '-r', '--repo',
        default='.',
        help='directory with git repository')
    parser.add_argument(
        '-d', '--max-diff',
        type=int, default=20,
        help='max different entries in chart: after this number, an entry is '
        'counted in "others" (for charts authors and files_type); max number '
        'of days (for chart commits_day); 0=unlimited')
    parser.add_argument(
        '-s', '--sort-max',
        type=int, default=0,
        help='keep max entries in chart and sort them by value; a negative '
        'number will reverse the sort (only for charts: commits_hour_day, '
        'commits_day, commits_day_week, commits_month, commits_year, '
        'commits_year_month, commits_version); 0=no sort/max')
    parser.add_argument(
        '-j', '--js',
        default=','.join(pygal_config.js),
        help='comma-separated list of the two javascript files/links used in '
        'SVG')
    parser.add_argument(
        'chart',
        metavar='chart', choices=sorted(GitChart.charts),
        help='{0}: {1}'.format('name of chart, one of',
                               ', '.join(sorted(GitChart.charts))))
    parser.add_argument(
        'output',
        help='output file (svg or png), special value "-" displays SVG '
        'content on standard output')
    parser.add_argument(
        '-v', '--version',
        action='version', version=VERSION)
    if len(sys.argv) == 1:
        parser.print_help()
        sys.exit(1)
    args = parser.parse_args(sys.argv[1:])

    # check javascript files
    js_list = args.js.split(',')
    if not js_list or len(js_list) != 2 or not js_list[0] or not js_list[1]:
        sys.exit('ERROR: invalid javascript files')

    # read data on standard input
    in_data = ''
    while True:
        inr = select.select([sys.stdin], [], [], 0)[0]
        if not inr:
            break
        data = os.read(sys.stdin.fileno(), 4096)
        if not data:
            break
        in_data += data.decode('utf-8')

    # generate chart
    chart = GitChart(args.chart, args.title, args.repo, args.output,
                     args.max_diff, args.sort_max, args.js, in_data)
    if chart.generate():
        sys.exit(0)

    # error
    print('ERROR: failed to generate chart:', vars(args))
    sys.exit(1)


if __name__ == "__main__":
    main()