diskimage-builder/diskimage_builder/block_device/utils.py
Ian Wienand 28ebd24844 Uncap hacking
This causes problems for other projects incorporating dib; we don't
have a specific need for a cap.

Fix a few issues, mostly spacing or regex matches.  No functional
changes.

W503 and W504 relate to leaving artithmetic operators at the start or
end of lines, and are mutually exclusive and, due to "ignore"
overriding the defaults both get enabled.  It seems everyone gets this
wrong (https://gitlab.com/pycqa/flake8/issues/466).  Don't take a
position on this and ignore both.

Use double # around comments including YAML snippets using "# type: "
which now gets detected as PEP484/mypy type hints.

Change-Id: I8b7ce6dee02dcce31c82427a2441c931d136ef57
2020-02-24 10:34:46 +11:00

146 lines
4.4 KiB
Python

# Copyright 2016 Andreas Florath (andreas@florath.net)
#
# Licensed under the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License. You may obtain
# a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.
import locale
import logging
import re
import subprocess
from diskimage_builder.block_device.exception import \
BlockDeviceSetupException
logger = logging.getLogger(__name__)
SIZE_UNIT_SPECS = [
["TiB", 1024**4],
["GiB", 1024**3],
["MiB", 1024**2],
["KiB", 1024**1],
["TB", 1000**4],
["GB", 1000**3],
["MB", 1000**2],
["KB", 1000**1],
["T", 1000**4],
["G", 1000**3],
["M", 1000**2],
["K", 1000**1],
["B", 1],
["", 1], # No unit -> size is given in bytes
]
# Basic RE to check and split floats (without exponent)
# and a given unit specification (which must be non-numerical).
size_unit_spec_re = re.compile(r"^([\d\.]*) ?([a-zA-Z0-9_]*)$")
def _split_size_unit_spec(size_unit_spec):
"""Helper function to split unit specification into parts.
The first part is the numeric part - the second one is the unit.
"""
match = size_unit_spec_re.match(size_unit_spec)
if match is None:
raise RuntimeError("Invalid size unit spec [%s]" % size_unit_spec)
return match.group(1), match.group(2)
def _get_unit_factor(unit_str):
"""Helper function to get the unit factor.
The given unit_str needs to be a string of the
SIZE_UNIT_SPECS table.
If the unit is not found, a runtime error is raised.
"""
for spec_key, spec_value in SIZE_UNIT_SPECS:
if unit_str == spec_key:
return spec_value
raise RuntimeError("unit_str [%s] not known" % unit_str)
def parse_abs_size_spec(size_spec):
size_cnt_str, size_unit_str = _split_size_unit_spec(size_spec)
unit_factor = _get_unit_factor(size_unit_str)
return int(unit_factor * (
float(size_cnt_str) if len(size_cnt_str) > 0 else 1))
def parse_rel_size_spec(size_spec, abs_size):
"""Parses size specifications - can be relative like 50%
In addition to the absolute parsing also a relative
parsing is done. If the size specification ends in '%',
then the relative size of the given 'abs_size' is returned.
"""
if size_spec[-1] == '%':
percent = float(size_spec[:-1])
return True, int(abs_size * percent / 100.0)
return False, parse_abs_size_spec(size_spec)
def exec_sudo(cmd):
"""Run a command under sudo
Run command under sudo, with debug trace of output. This is like
subprocess.check_call() but sudo wrapped and with output tracing
at debug levels.
Arguments:
:param cmd: str command list; for Popen()
:return: the stdout+stderror of the called command
:raises BlockDeviceSetupException: if return code != 0.
Exception values similar to ``subprocess.CalledProcessError``
* ``returncode`` : returncode of child
* ``cmd`` : the command run
* ``output`` : stdout+stderr output
"""
assert isinstance(cmd, list)
sudo_cmd = ["sudo"]
sudo_cmd.extend(cmd)
try:
logger.info("Calling [%s]", " ".join(sudo_cmd))
except TypeError:
# Popen actually doesn't care, but we've managed to get mixed
# str and bytes in argument lists which causes errors logging
# commands. Give a clue as to what's going on.
logger.exception("Ensure all arguments are str type!")
raise
proc = subprocess.Popen(sudo_cmd,
stdout=subprocess.PIPE,
stderr=subprocess.STDOUT)
out = ""
with proc.stdout:
for line in iter(proc.stdout.readline, b''):
line = line.decode(encoding=locale.getpreferredencoding(False),
errors='backslashreplace')
out += line
logger.debug("exec_sudo: %s", line.rstrip())
proc.wait()
if proc.returncode:
e = BlockDeviceSetupException("exec_sudo failed")
e.returncode = proc.returncode
e.cmd = ' '.join(sudo_cmd)
e.output = out
raise e
return out