1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
build / compute_build_timestamp.py [blame]
#!/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())