blob: 6fe514fd7885a6654f774daa2b048970fa87f79c [file] [log] [blame]
#!/usr/bin/env python
# Copyright (c) 2016 The Chromium Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.
"""Writes a file that contains a define that approximates the build date.
build_type impacts the timestamp generated:
- default: the build date is set to the most recent first Sunday of a month at
5:00am. The reason is that it is a time where invalidating the build cache
shouldn't have major reprecussions (due to lower load).
- official: the build date is set to the current date at 5:00am, or the day
before if the current time is before 5:00am.
Either way, it is guaranteed to be in the past and always in UTC.
It is also possible to explicitly set a build date to be used.
import argparse
import calendar
import datetime
import doctest
import os
import sys
def GetFirstSundayOfMonth(year, month):
"""Returns the first sunday of the given month of the given year.
>>> GetFirstSundayOfMonth(2016, 2)
>>> GetFirstSundayOfMonth(2016, 3)
>>> GetFirstSundayOfMonth(2000, 1)
weeks = calendar.Calendar().monthdays2calendar(year, month)
# Return the first day in the first week that is a Sunday.
return [date_day[0] for date_day in weeks[0] if date_day[1] == 6][0]
def GetBuildDate(build_type, utc_now):
"""Gets the approximate build date given the specific build type.
>>> GetBuildDate('default', datetime.datetime(2016, 2, 6, 1, 2, 3))
'Jan 03 2016 01:02:03'
>>> GetBuildDate('default', datetime.datetime(2016, 2, 7, 5))
'Feb 07 2016 05:00:00'
>>> GetBuildDate('default', datetime.datetime(2016, 2, 8, 5))
'Feb 07 2016 05:00:00'
day =
month = utc_now.month
year = utc_now.year
if build_type != 'official':
first_sunday = GetFirstSundayOfMonth(year, month)
# If our build is after the first Sunday, we've already refreshed our build
# cache on a quiet day, so just use that day.
# Otherwise, take the first Sunday of the previous month.
if day >= first_sunday:
day = first_sunday
month -= 1
if month == 0:
month = 12
year -= 1
day = GetFirstSundayOfMonth(year, month)
now = datetime.datetime(
year, month, day, utc_now.hour, utc_now.minute, utc_now.second)
return '{:%b %d %Y %H:%M:%S}'.format(now)
def main():
if doctest.testmod()[0]:
return 1
argument_parser = argparse.ArgumentParser(
argument_parser.add_argument('output_file', help='The file to write to')
'build_type', help='The type of build', choices=('official', 'default'))
'build_date_override', nargs='?',
help='Optional override for the build date. Format must be '
'\'Mmm DD YYYY HH:MM:SS\'')
args = argument_parser.parse_args()
if args.build_date_override:
# Format is expected to be "Mmm DD YYYY HH:MM:SS".
build_date = args.build_date_override
now = datetime.datetime.utcnow()
if now.hour < 5:
# The time is locked at 5:00 am in UTC to cause the build cache
# invalidation to not happen exactly at midnight. Use the same calculation
# as the day before.
# See //base/
now = now - datetime.timedelta(days=1)
now = datetime.datetime(now.year, now.month,, 5, 0, 0)
build_date = GetBuildDate(args.build_type, now)
output = ('// Generated by //build/\n'
'#ifndef BUILD_DATE\n'
'#define BUILD_DATE "{}"\n'
'#endif // BUILD_DATE\n'.format(build_date))
current_contents = ''
if os.path.isfile(args.output_file):
with open(args.output_file, 'r') as current_file:
current_contents =
if current_contents != output:
with open(args.output_file, 'w') as output_file:
return 0
if __name__ == '__main__':