| #!/usr/bin/env python3 |
| # Copyright 2018 The Chromium Authors |
| # Use of this source code is governed by a BSD-style license that can be |
| # found in the LICENSE file. |
| """Returns a timestamp that approximates the build date. |
| |
| build_type impacts the timestamp generated, both relative to the date of the |
| last recent commit: |
| - 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 repercussions (due to lower load). |
| - official: the build date is set to the time of the most recent commit. |
| Either way, it is guaranteed to be in the past and always in UTC. |
| """ |
| |
| # The requirements for the timestamp: |
| # (1) for the purposes of continuous integration, longer duration |
| # between cache invalidation is better, but >=1mo is preferable. |
| # (2) for security purposes, timebombs would ideally be as close to |
| # the actual time of the build as possible. It must be in the past. |
| # (3) HSTS certificate pinning is valid for 70 days. To make CI builds enforce |
| # HTST pinning, <=1mo is preferable. |
| # |
| # On Windows, the timestamp is also written in the PE/COFF file header of |
| # executables of dlls. That timestamp and the executable's file size are |
| # the only two pieces of information that identify a given executable on |
| # the symbol server, so rarely changing timestamps can cause conflicts there |
| # as well. We only upload symbols for official builds to the symbol server. |
| |
| |
| import argparse |
| import calendar |
| import datetime |
| import doctest |
| import os |
| import sys |
| |
| |
| THIS_DIR = os.path.abspath(os.path.dirname(__file__)) |
| |
| |
| def GetFirstSundayOfMonth(year, month): |
| """Returns the first sunday of the given month of the given year. |
| |
| >>> GetFirstSundayOfMonth(2016, 2) |
| 7 |
| >>> GetFirstSundayOfMonth(2016, 3) |
| 6 |
| >>> GetFirstSundayOfMonth(2000, 1) |
| 2 |
| """ |
| 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 GetUnofficialBuildDate(build_date): |
| """Gets the approximate build date given the specific build type. |
| |
| >>> GetUnofficialBuildDate(datetime.datetime(2016, 2, 6, 1, 2, 3)) |
| datetime.datetime(2016, 1, 3, 5, 0) |
| >>> GetUnofficialBuildDate(datetime.datetime(2016, 2, 7, 5)) |
| datetime.datetime(2016, 2, 7, 5, 0) |
| >>> GetUnofficialBuildDate(datetime.datetime(2016, 2, 8, 5)) |
| datetime.datetime(2016, 2, 7, 5, 0) |
| """ |
| |
| if build_date.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/build_time.cc. |
| build_date = build_date - datetime.timedelta(days=1) |
| build_date = datetime.datetime(build_date.year, build_date.month, |
| build_date.day, 5, 0, 0) |
| |
| day = build_date.day |
| month = build_date.month |
| year = build_date.year |
| 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 |
| else: |
| month -= 1 |
| if month == 0: |
| month = 12 |
| year -= 1 |
| day = GetFirstSundayOfMonth(year, month) |
| return datetime.datetime( |
| year, month, day, build_date.hour, build_date.minute, build_date.second) |
| |
| |
| def main(): |
| if doctest.testmod()[0]: |
| return 1 |
| argument_parser = argparse.ArgumentParser() |
| argument_parser.add_argument( |
| 'build_type', help='The type of build', choices=('official', 'default')) |
| args = argument_parser.parse_args() |
| |
| # The mtime of the revision in build/util/LASTCHANGE is stored in a file |
| # next to it. Read it, to get a deterministic time close to "now". |
| # That date is then modified as described at the top of the file so that |
| # it changes less frequently than with every commit. |
| # This intentionally always uses build/util/LASTCHANGE's commit time even if |
| # use_dummy_lastchange is set. |
| lastchange_file = os.path.join(THIS_DIR, 'util', 'LASTCHANGE.committime') |
| last_commit_timestamp = int(open(lastchange_file).read()) |
| build_date = datetime.datetime.fromtimestamp(last_commit_timestamp, |
| datetime.timezone.utc) |
| |
| # For official builds we want full fidelity time stamps because official |
| # builds are typically added to symbol servers and Windows symbol servers |
| # use the link timestamp as the prime differentiator, but for unofficial |
| # builds we do lots of quantization to avoid churn. |
| offset = 0 |
| if args.build_type == 'official': |
| if os.name == 'nt': |
| version_path = os.path.join(THIS_DIR, os.pardir, 'chrome', 'VERSION') |
| with open(version_path) as f: |
| patch_line = f.readlines()[3].strip() |
| # Use the patch number as an offset to the build date so that multiple |
| # versions with different patch numbers built from the same source code |
| # will get different build_date values. This is critical for Windows |
| # symbol servers, to avoid collisions. |
| assert patch_line.startswith('PATCH=') |
| offset = int(patch_line[6:]) |
| else: |
| build_date = GetUnofficialBuildDate(build_date) |
| print(offset + int(calendar.timegm(build_date.utctimetuple()))) |
| return 0 |
| |
| |
| if __name__ == '__main__': |
| sys.exit(main()) |