ironic-python-agent/ironic_python_agent/utils.py
Dmitry Tantsur 58f86d0353 Stop trying to log stdout when fetching logs during inspection
Logging the whole journalctl output is not the best idea. Fortunately,
it does not work right now and fails with a traceback :)

This change adds a new log_stdout argument to utils.execute() and uses it in
the "logs" inspection collector.

Also do not log the logs while logging the collected data.

Change-Id: Ibc726ac2c4f5eb06c73ac4765bb400077b84a6cc
2016-03-08 16:31:18 +01:00

341 lines
12 KiB
Python

# Copyright 2013 Rackspace, Inc.
#
# 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 copy
import glob
import os
import shutil
import tempfile
from oslo_concurrency import processutils
from oslo_log import log as logging
from oslo_utils import units
from six.moves.urllib import parse
from ironic_python_agent import errors
LOG = logging.getLogger(__name__)
SUPPORTED_ROOT_DEVICE_HINTS = set(('size', 'model', 'wwn', 'serial', 'vendor'))
# Agent parameters can be passed by kernel command-line arguments and/or
# by virtual media. Virtual media parameters passed would be available
# when the agent is started, but might not be available for re-reading
# later on because:
# * Virtual media might be exposed from Swift and swift temp url might
# expire.
# * Ironic might have removed the floppy image from Swift after starting
# the deploy.
#
# Even if it's available, there is no need to re-read from the device and
# /proc/cmdline again, because it is never going to change. So we cache the
# agent parameters that was passed (by proc/cmdline and/or virtual media)
# when we read it for the first time, and then use this cache.
AGENT_PARAMS_CACHED = dict()
def execute(*cmd, **kwargs):
"""Convenience wrapper around oslo's execute() method.
Executes and logs results from a system command. See docs for
oslo_concurrency.processutils.execute for usage.
:param *cmd: positional arguments to pass to processutils.execute()
:param log_stdout: keyword-only argument: whether to log the output
:param **kwargs: keyword arguments to pass to processutils.execute()
:raises: UnknownArgumentError on receiving unknown arguments
:raises: ProcessExecutionError
:raises: OSError
:returns: tuple of (stdout, stderr)
"""
log_stdout = kwargs.pop('log_stdout', True)
result = processutils.execute(*cmd, **kwargs)
LOG.debug('Execution completed, command line is "%s"', ' '.join(cmd))
if log_stdout:
LOG.debug('Command stdout is: "%s"', result[0])
LOG.debug('Command stderr is: "%s"', result[1])
return result
def try_execute(*cmd, **kwargs):
"""The same as execute but returns None on error.
Executes and logs results from a system command. See docs for
oslo_concurrency.processutils.execute for usage.
Instead of raising an exception on failure, this method simply
returns None in case of failure.
:param *cmd: positional arguments to pass to processutils.execute()
:param log_stdout: keyword-only argument: whether to log the output
:param **kwargs: keyword arguments to pass to processutils.execute()
:raises: UnknownArgumentError on receiving unknown arguments
:returns: tuple of (stdout, stderr) or None in some error cases
"""
try:
return execute(*cmd, **kwargs)
except (processutils.ProcessExecutionError, OSError) as e:
LOG.debug('Command failed: %s', e)
def _read_params_from_file(filepath):
"""Extract key=value pairs from a file.
:param filepath: path to a file containing key=value pairs separated by
whitespace or newlines.
:returns: a dictionary representing the content of the file
"""
with open(filepath) as f:
cmdline = f.read()
options = cmdline.split()
params = {}
for option in options:
if '=' not in option:
continue
k, v = option.split('=', 1)
params[k] = v
return params
def _get_vmedia_device():
"""Finds the device filename of the virtual media device using sysfs.
:returns: a string containing the filename of the virtual media device
"""
sysfs_device_models = glob.glob("/sys/class/block/*/device/model")
vmedia_device_model = "virtual media"
for model_file in sysfs_device_models:
try:
with open(model_file) as model_file_fobj:
if vmedia_device_model in model_file_fobj.read().lower():
vmedia_device = model_file.split('/')[4]
return vmedia_device
except Exception:
pass
def _get_vmedia_params():
"""This method returns the parameters passed through virtual media floppy.
:returns: a partial dict of potential agent configuration parameters
:raises: VirtualMediaBootError when it cannot find the virtual media device
"""
parameters_file = "parameters.txt"
vmedia_device_file_lower_case = "/dev/disk/by-label/ir-vfd-dev"
vmedia_device_file_upper_case = "/dev/disk/by-label/IR-VFD-DEV"
if os.path.exists(vmedia_device_file_lower_case):
vmedia_device_file = vmedia_device_file_lower_case
elif os.path.exists(vmedia_device_file_upper_case):
vmedia_device_file = vmedia_device_file_upper_case
else:
# TODO(rameshg87): This block of code is there only for compatibility
# reasons (so that newer agent can work with older Ironic). Remove
# this after Liberty release.
vmedia_device = _get_vmedia_device()
if not vmedia_device:
msg = "Unable to find virtual media device"
raise errors.VirtualMediaBootError(msg)
vmedia_device_file = os.path.join("/dev", vmedia_device)
vmedia_mount_point = tempfile.mkdtemp()
try:
try:
stdout, stderr = execute("mount", vmedia_device_file,
vmedia_mount_point)
except processutils.ProcessExecutionError as e:
msg = ("Unable to mount virtual media device %(device)s: "
"%(error)s" % {'device': vmedia_device_file, 'error': e})
raise errors.VirtualMediaBootError(msg)
parameters_file_path = os.path.join(vmedia_mount_point,
parameters_file)
params = _read_params_from_file(parameters_file_path)
try:
stdout, stderr = execute("umount", vmedia_mount_point)
except processutils.ProcessExecutionError as e:
pass
finally:
try:
shutil.rmtree(vmedia_mount_point)
except Exception as e:
pass
return params
def _get_cached_params():
"""Helper method to get cached params to ease unit testing."""
return AGENT_PARAMS_CACHED
def _set_cached_params(params):
"""Helper method to set cached params to ease unit testing."""
global AGENT_PARAMS_CACHED
AGENT_PARAMS_CACHED = params
def get_agent_params():
"""Gets parameters passed to the agent via kernel cmdline or vmedia.
Parameters can be passed using either the kernel commandline or through
virtual media. If boot_method is vmedia, merge params provided via vmedia
with those read from the kernel command line.
Although it should never happen, if a variable is both set by vmedia and
kernel command line, the setting in vmedia will take precedence.
:returns: a dict of potential configuration parameters for the agent
"""
# Check if we have the parameters cached
params = _get_cached_params()
if not params:
params = _read_params_from_file('/proc/cmdline')
# If the node booted over virtual media, the parameters are passed
# in a text file within the virtual media floppy.
if params.get('boot_method') == 'vmedia':
vmedia_params = _get_vmedia_params()
params.update(vmedia_params)
# Cache the parameters so that it can be used later on.
_set_cached_params(params)
return copy.deepcopy(params)
def normalize(string):
"""Return a normalized string.
Take a urlencoded value from Ironic and urldecode it.
:param string: a urlencoded string
:returns: a normalized version of passed in string
"""
return parse.unquote(string).lower().strip()
def parse_root_device_hints():
"""Parse the root device hints.
Parse the root device hints given by Ironic via kernel cmdline
or vmedia.
:returns: A dict with the hints or an empty dict if no hints are
passed.
:raises: DeviceNotFound if there are unsupported hints.
"""
root_device = get_agent_params().get('root_device')
if not root_device:
return {}
hints = dict((item.split('=') for item in root_device.split(',')))
# Find invalid hints for logging
not_supported = set(hints) - SUPPORTED_ROOT_DEVICE_HINTS
if not_supported:
error_msg = ('No device can be found because the following hints: '
'"%(not_supported)s" are not supported by this version '
'of IPA. Supported hints are: "%(supported)s"',
{'not_supported': ', '.join(not_supported),
'supported': ', '.join(SUPPORTED_ROOT_DEVICE_HINTS)})
raise errors.DeviceNotFound(error_msg)
# Normalise the values
hints = {k: normalize(v) for k, v in hints.items()}
if 'size' in hints:
# NOTE(lucasagomes): Ironic should validate before passing to
# the deploy ramdisk
hints['size'] = int(hints['size'])
return hints
class AccumulatedFailures(object):
"""Object to accumulate failures without raising exception."""
def __init__(self, exc_class=RuntimeError):
self._failures = []
self._exc_class = exc_class
def add(self, fail, *fmt):
"""Add failure with optional formatting.
:param fail: exception or error string
:param fmt: formatting arguments (only if fail is a string)
"""
if fmt:
fail = fail % fmt
LOG.error('%s', fail)
self._failures.append(fail)
def get_error(self):
"""Get error string or None."""
if not self._failures:
return
msg = ('The following errors were encountered:\n%s'
% '\n'.join('* %s' % item for item in self._failures))
return msg
def raise_if_needed(self):
"""Raise exception if error list is not empty.
:raises: RuntimeError
"""
if self._failures:
raise self._exc_class(self.get_error())
def __nonzero__(self):
return bool(self._failures)
__bool__ = __nonzero__
def __repr__(self): # pragma: no cover
# This is for tests
if self:
return '<%s: %s>' % (self.__class__.__name__,
', '.join(self._failures))
else:
return '<%s: success>' % self.__class__.__name__
def guess_root_disk(block_devices, min_size_required=4 * units.Gi):
"""Find suitable disk provided that root device hints are not given.
If no hints are passed find the first device larger than min_size_required,
assume it is the OS disk
"""
# TODO(russellhaering): This isn't a valid assumption in
# all cases, is there a more reasonable default behavior?
block_devices.sort(key=lambda device: device.size)
if not block_devices or block_devices[-1].size < min_size_required:
raise errors.DeviceNotFound(
"No suitable device was found "
"for deployment - root device hints were not provided "
"and all found block devices are smaller than %iB."
% min_size_required)
for device in block_devices:
if device.size >= min_size_required:
return device