diskimage-builder/diskimage_builder/block_device/utils.py
Ian Wienand 0d8c4270c0 exec_sudo: check cmd for str, log output and raise exception
To avoid any confusion, commands passed to exec_sudo() should be a
list of "str"s.  Log a message if we see unicode issues.

This also adds a debug trace of all output.  stderr is captured.

This is modified to raise CalledProcessError on failure, like
check_call().  Calls that are ok to fail will need to explicitly catch
and ignore this.

The two calls that we expect to fail are wrapped

We wish to try rolling back if one of these command raises an
exception.  Modify the create handler to initiate rollback on all
exceptions.

Change-Id: Iee4fa41ffaf243e4728bf3a5eeec5c8fa8d2dadc
2017-05-11 09:45:25 +10:00

145 lines
4.5 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 logging
import re
import subprocess
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("^([\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: nothing
:raises: subprocess.CalledProcessError if return code != 0
"""
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)
for line in iter(proc.stdout.readline, b""):
logger.debug("exec_sudo: %s" % line.rstrip())
proc.wait()
if proc.returncode != 0:
raise subprocess.CalledProcessError(proc.returncode,
' '.join(sudo_cmd))
def sort_mount_points(mount_points):
logger.debug("sort_mount_points called [%s]" % mount_points)
def insert_sorted(mp, sorted_mount_points):
if len(sorted_mount_points) == 0:
sorted_mount_points.append(mp)
return
for idx in range(0, len(sorted_mount_points)):
if sorted_mount_points[idx].startswith(mp):
sorted_mount_points.insert(idx, mp)
return
sorted_mount_points.append(mp)
sorted_mount_points = []
for mp in mount_points:
insert_sorted(mp, sorted_mount_points)
logger.debug("sort_mount_points result [%s]" % sorted_mount_points)
return sorted_mount_points