bpo-28468: Add platform.freedesktop_os_release() (GH-23492)

Add platform.freedesktop_os_release() function to parse freedesktop.org
os-release files.

Signed-off-by: Christian Heimes <christian@python.org>
Co-authored-by: Victor Stinner <vstinner@python.org>
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Christian Heimes 2020-11-30 22:34:45 +01:00 committed by GitHub
parent 9bdc40ee3e
commit 5c73afc36e
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@ -253,3 +253,41 @@ Unix Platforms
using :program:`gcc`.
The file is read and scanned in chunks of *chunksize* bytes.
Linux Platforms
---------------
.. function:: freedesktop_os_release()
Get operating system identification from ``os-release`` file and return
it as a dict. The ``os-release`` file is a `freedesktop.org standard
<https://www.freedesktop.org/software/systemd/man/os-release.html>`_ and
is available in most Linux distributions. A noticeable exception is
Android and Android-based distributions.
Raises :exc:`OSError` or subclass when neither ``/etc/os-release`` nor
``/usr/lib/os-release`` can be read.
On success, the function returns a dictionary where keys and values are
strings. Values have their special characters like ``"`` and ``$``
unquoted. The fields ``NAME``, ``ID``, and ``PRETTY_NAME`` are always
defined according to the standard. All other fields are optional. Vendors
may include additional fields.
Note that fields like ``NAME``, ``VERSION``, and ``VARIANT`` are strings
suitable for presentation to users. Programs should use fields like
``ID``, ``ID_LIKE``, ``VERSION_ID``, or ``VARIANT_ID`` to identify
Linux distributions.
Example::
def get_like_distro():
info = platform.freedesktop_os_release()
ids = [info["ID"]]
if "ID_LIKE" in info:
# ids are space separated and ordered by precedence
ids.extend(info["ID_LIKE"].split())
return ids
.. versionadded:: 3.10

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@ -254,6 +254,14 @@ Added negative indexing support to :attr:`PurePath.parents
<pathlib.PurePath.parents>`.
(Contributed by Yaroslav Pankovych in :issue:`21041`)
platform
--------
Added :func:`platform.freedesktop_os_release()` to retrieve operation system
identification from `freedesktop.org os-release
<https://www.freedesktop.org/software/systemd/man/os-release.html>`_ standard file.
(Contributed by Christian Heimes in :issue:`28468`)
py_compile
----------

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@ -1230,6 +1230,63 @@ def platform(aliased=0, terse=0):
_platform_cache[(aliased, terse)] = platform
return platform
### freedesktop.org os-release standard
# https://www.freedesktop.org/software/systemd/man/os-release.html
# NAME=value with optional quotes (' or "). The regular expression is less
# strict than shell lexer, but that's ok.
_os_release_line = re.compile(
"^(?P<name>[a-zA-Z0-9_]+)=(?P<quote>[\"\']?)(?P<value>.*)(?P=quote)$"
)
# unescape five special characters mentioned in the standard
_os_release_unescape = re.compile(r"\\([\\\$\"\'`])")
# /etc takes precedence over /usr/lib
_os_release_candidates = ("/etc/os-release", "/usr/lib/os-relesase")
_os_release_cache = None
def _parse_os_release(lines):
# These fields are mandatory fields with well-known defaults
# in pratice all Linux distributions override NAME, ID, and PRETTY_NAME.
info = {
"NAME": "Linux",
"ID": "linux",
"PRETTY_NAME": "Linux",
}
for line in lines:
mo = _os_release_line.match(line)
if mo is not None:
info[mo.group('name')] = _os_release_unescape.sub(
r"\1", mo.group('value')
)
return info
def freedesktop_os_release():
"""Return operation system identification from freedesktop.org os-release
"""
global _os_release_cache
if _os_release_cache is None:
errno = None
for candidate in _os_release_candidates:
try:
with open(candidate, encoding="utf-8") as f:
_os_release_cache = _parse_os_release(f)
break
except OSError as e:
errno = e.errno
else:
raise OSError(
errno,
f"Unable to read files {', '.join(_os_release_candidates)}"
)
return _os_release_cache.copy()
### Command line interface
if __name__ == '__main__':

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@ -8,12 +8,70 @@ from unittest import mock
from test import support
from test.support import os_helper
FEDORA_OS_RELEASE = """\
NAME=Fedora
VERSION="32 (Thirty Two)"
ID=fedora
VERSION_ID=32
VERSION_CODENAME=""
PLATFORM_ID="platform:f32"
PRETTY_NAME="Fedora 32 (Thirty Two)"
ANSI_COLOR="0;34"
LOGO=fedora-logo-icon
CPE_NAME="cpe:/o:fedoraproject:fedora:32"
HOME_URL="https://fedoraproject.org/"
DOCUMENTATION_URL="https://docs.fedoraproject.org/en-US/fedora/f32/system-administrators-guide/"
SUPPORT_URL="https://fedoraproject.org/wiki/Communicating_and_getting_help"
BUG_REPORT_URL="https://bugzilla.redhat.com/"
REDHAT_BUGZILLA_PRODUCT="Fedora"
REDHAT_BUGZILLA_PRODUCT_VERSION=32
REDHAT_SUPPORT_PRODUCT="Fedora"
REDHAT_SUPPORT_PRODUCT_VERSION=32
PRIVACY_POLICY_URL="https://fedoraproject.org/wiki/Legal:PrivacyPolicy"
"""
UBUNTU_OS_RELEASE = """\
NAME="Ubuntu"
VERSION="20.04.1 LTS (Focal Fossa)"
ID=ubuntu
ID_LIKE=debian
PRETTY_NAME="Ubuntu 20.04.1 LTS"
VERSION_ID="20.04"
HOME_URL="https://www.ubuntu.com/"
SUPPORT_URL="https://help.ubuntu.com/"
BUG_REPORT_URL="https://bugs.launchpad.net/ubuntu/"
PRIVACY_POLICY_URL="https://www.ubuntu.com/legal/terms-and-policies/privacy-policy"
VERSION_CODENAME=focal
UBUNTU_CODENAME=focal
"""
TEST_OS_RELEASE = r"""
# test data
ID_LIKE="egg spam viking"
EMPTY=
# comments and empty lines are ignored
SINGLE_QUOTE='single'
EMPTY_SINGLE=''
DOUBLE_QUOTE="double"
EMPTY_DOUBLE=""
QUOTES="double\'s"
SPECIALS="\$\`\\\'\""
# invalid lines
=invalid
=
INVALID
IN-VALID=value
IN VALID=value
"""
class PlatformTest(unittest.TestCase):
def clear_caches(self):
platform._platform_cache.clear()
platform._sys_version_cache.clear()
platform._uname_cache = None
platform._os_release_cache = None
def test_architecture(self):
res = platform.architecture()
@ -382,6 +440,54 @@ class PlatformTest(unittest.TestCase):
self.assertEqual(platform.platform(terse=1), expected_terse)
self.assertEqual(platform.platform(), expected)
def test_freedesktop_os_release(self):
self.addCleanup(self.clear_caches)
self.clear_caches()
if any(os.path.isfile(fn) for fn in platform._os_release_candidates):
info = platform.freedesktop_os_release()
self.assertIn("NAME", info)
self.assertIn("ID", info)
info["CPYTHON_TEST"] = "test"
self.assertNotIn(
"CPYTHON_TEST",
platform.freedesktop_os_release()
)
else:
with self.assertRaises(OSError):
platform.freedesktop_os_release()
def test_parse_os_release(self):
info = platform._parse_os_release(FEDORA_OS_RELEASE.splitlines())
self.assertEqual(info["NAME"], "Fedora")
self.assertEqual(info["ID"], "fedora")
self.assertNotIn("ID_LIKE", info)
self.assertEqual(info["VERSION_CODENAME"], "")
info = platform._parse_os_release(UBUNTU_OS_RELEASE.splitlines())
self.assertEqual(info["NAME"], "Ubuntu")
self.assertEqual(info["ID"], "ubuntu")
self.assertEqual(info["ID_LIKE"], "debian")
self.assertEqual(info["VERSION_CODENAME"], "focal")
info = platform._parse_os_release(TEST_OS_RELEASE.splitlines())
expected = {
"ID": "linux",
"NAME": "Linux",
"PRETTY_NAME": "Linux",
"ID_LIKE": "egg spam viking",
"EMPTY": "",
"DOUBLE_QUOTE": "double",
"EMPTY_DOUBLE": "",
"SINGLE_QUOTE": "single",
"EMPTY_SINGLE": "",
"QUOTES": "double's",
"SPECIALS": "$`\\'\"",
}
self.assertEqual(info, expected)
self.assertEqual(len(info["SPECIALS"]), 5)
if __name__ == '__main__':
unittest.main()

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@ -0,0 +1,2 @@
Add :func:`platform.freedesktop_os_release` function to parse freedesktop.org
``os-release`` files.