python (3.11.7)
1 """
2 Script to automatically generate a JSON file containing time zone information.
3
4 This is done to allow "pinning" a small subset of the tzdata in the tests,
5 since we are testing properties of a file that may be subject to change. For
6 example, the behavior in the far future of any given zone is likely to change,
7 but "does this give the right answer for this file in 2040" is still an
8 important property to test.
9
10 This must be run from a computer with zoneinfo data installed.
11 """
12 from __future__ import annotations
13
14 import base64
15 import functools
16 import json
17 import lzma
18 import pathlib
19 import textwrap
20 import typing
21
22 import zoneinfo
23
24 KEYS = [
25 "Africa/Abidjan",
26 "Africa/Casablanca",
27 "America/Los_Angeles",
28 "America/Santiago",
29 "Asia/Tokyo",
30 "Australia/Sydney",
31 "Europe/Dublin",
32 "Europe/Lisbon",
33 "Europe/London",
34 "Pacific/Kiritimati",
35 "UTC",
36 ]
37
38 TEST_DATA_LOC = pathlib.Path(__file__).parent
39
40
41 @functools.lru_cache(maxsize=None)
42 def get_zoneinfo_path() -> pathlib.Path:
43 """Get the first zoneinfo directory on TZPATH containing the "UTC" zone."""
44 key = "UTC"
45 for path in map(pathlib.Path, zoneinfo.TZPATH):
46 if (path / key).exists():
47 return path
48 else:
49 raise OSError("Cannot find time zone data.")
50
51
52 def get_zoneinfo_metadata() -> typing.Dict[str, str]:
53 path = get_zoneinfo_path()
54
55 tzdata_zi = path / "tzdata.zi"
56 if not tzdata_zi.exists():
57 # tzdata.zi is necessary to get the version information
58 raise OSError("Time zone data does not include tzdata.zi.")
59
60 with open(tzdata_zi, "r") as f:
61 version_line = next(f)
62
63 _, version = version_line.strip().rsplit(" ", 1)
64
65 if (
66 not version[0:4].isdigit()
67 or len(version) < 5
68 or not version[4:].isalpha()
69 ):
70 raise ValueError(
71 "Version string should be YYYYx, "
72 + "where YYYY is the year and x is a letter; "
73 + f"found: {version}"
74 )
75
76 return {"version": version}
77
78
79 def get_zoneinfo(key: str) -> bytes:
80 path = get_zoneinfo_path()
81
82 with open(path / key, "rb") as f:
83 return f.read()
84
85
86 def encode_compressed(data: bytes) -> typing.List[str]:
87 compressed_zone = lzma.compress(data)
88 raw = base64.b85encode(compressed_zone)
89
90 raw_data_str = raw.decode("utf-8")
91
92 data_str = textwrap.wrap(raw_data_str, width=70)
93 return data_str
94
95
96 def load_compressed_keys() -> typing.Dict[str, typing.List[str]]:
97 output = {key: encode_compressed(get_zoneinfo(key)) for key in KEYS}
98
99 return output
100
101
102 def update_test_data(fname: str = "zoneinfo_data.json") -> None:
103 TEST_DATA_LOC.mkdir(exist_ok=True, parents=True)
104
105 # Annotation required: https://github.com/python/mypy/issues/8772
106 json_kwargs: typing.Dict[str, typing.Any] = dict(
107 indent=2, sort_keys=True,
108 )
109
110 compressed_keys = load_compressed_keys()
111 metadata = get_zoneinfo_metadata()
112 output = {
113 "metadata": metadata,
114 "data": compressed_keys,
115 }
116
117 with open(TEST_DATA_LOC / fname, "w") as f:
118 json.dump(output, f, **json_kwargs)
119
120
121 if __name__ == "__main__":
122 update_test_data()
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