text: # Copyright 2010 United States Government as represented by the
  # Administrator of the National Aeronautics and Space Administration.
  # Copyright 2011 Justin Santa Barbara
  # Copyright (c) 2012 NTT DOCOMO, INC.
  # All Rights Reserved.
  #
  #    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.
  
  """Utilities and helper functions."""
  
  import contextlib
  import datetime
  import errno
  import hashlib
  import ipaddress
  import os
  import re
  import shutil
  import tempfile
  import time
  
  import jinja2
  from oslo_concurrency import processutils
  from oslo_log import log as logging
  from oslo_serialization import jsonutils
  from oslo_utils import fileutils
  from oslo_utils import netutils
  from oslo_utils import timeutils
  import psutil
  import pytz
  
  from ironic.common import exception
  from ironic.common.i18n import _
  from ironic.conf import CONF
  
  LOG = logging.getLogger(__name__)
  
  DATE_RE = r'(?P<year>-?\d{4,})-(?P<month>\d{2})-(?P<day>\d{2})'
  TIME_RE = r'(?P<hour>\d{2}):(?P<min>\d{2}):(?P<sec>\d{2})' + \
            r'(\.(?P<sec_frac>\d+))?'
  TZ_RE = r'((?P<tz_sign>[+-])(?P<tz_hour>\d{2}):(?P<tz_min>\d{2}))' + \
          r'|(?P<tz_z>Z)'
  
  DATETIME_RE = re.compile(
      '%sT%s(%s)?' % (DATE_RE, TIME_RE, TZ_RE))
  
  
  def _get_root_helper():
      # NOTE(jlvillal): This function has been moved to ironic-lib. And is
      # planned to be deleted here. If need to modify this function, please
      # also do the same modification in ironic-lib
      return 'sudo ironic-rootwrap %s' % CONF.rootwrap_config
  
  
  def execute(*cmd, **kwargs):
      """Convenience wrapper around oslo's execute() method.
  
      :param cmd: Passed to processutils.execute.
      :param use_standard_locale: True | False. Defaults to False. If set to
                                  True, execute command with standard locale
                                  added to environment variables.
      :returns: (stdout, stderr) from process execution
      :raises: UnknownArgumentError
      :raises: ProcessExecutionError
      """
  
      use_standard_locale = kwargs.pop('use_standard_locale', False)
      if use_standard_locale:
          env = kwargs.pop('env_variables', os.environ.copy())
          env['LC_ALL'] = 'C'
          kwargs['env_variables'] = env
      if kwargs.get('run_as_root') and 'root_helper' not in kwargs:
          kwargs['root_helper'] = _get_root_helper()
      result = processutils.execute(*cmd, **kwargs)
      LOG.debug('Execution completed, command line is "%s"',
                ' '.join(map(str, cmd)))
      LOG.debug('Command stdout is: "%s"', result[0])
      LOG.debug('Command stderr is: "%s"', result[1])
      return result
  
  
  def is_valid_datapath_id(datapath_id):
      """Verify the format of an OpenFlow datapath_id.
  
      Check if a datapath_id is valid and contains 16 hexadecimal digits.
      Datapath ID format: the lower 48-bits are for a MAC address,
      while the upper 16-bits are implementer-defined.
  
      :param datapath_id: OpenFlow datapath_id to be validated.
      :returns: True if valid. False if not.
  
      """
      m = "^[0-9a-f]{16}$"
      return (isinstance(datapath_id, str)
              and re.match(m, datapath_id.lower()))
  
  
  _is_valid_logical_name_re = re.compile(r'^[A-Z0-9-._~]+$', re.I)
  
  # old is_hostname_safe() regex, retained for backwards compat
  _is_hostname_safe_re = re.compile(r"""^
  [a-z0-9]([a-z0-9\-]{0,61}[a-z0-9])?  # host
  (\.[a-z0-9\-_]{0,62}[a-z0-9])*       # domain
  \.?                                  # trailing dot
  $""", re.X)
  
  
  def is_valid_logical_name(hostname):
      """Determine if a logical name is valid.
  
      The logical name may only consist of RFC3986 unreserved
      characters, to wit:
  
          ALPHA / DIGIT / "-" / "." / "_" / "~"
      """
      if not isinstance(hostname, str) or len(hostname) > 255:
          return False
  
      return _is_valid_logical_name_re.match(hostname) is not None
  
  
  def is_hostname_safe(hostname):
      """Old check for valid logical node names.
  
      Retained for compatibility with REST API < 1.10.
  
      Nominally, checks that the supplied hostname conforms to:
          * http://en.wikipedia.org/wiki/Hostname
          * http://tools.ietf.org/html/rfc952
          * http://tools.ietf.org/html/rfc1123
  
      In practice, this check has several shortcomings and errors that
      are more thoroughly documented in bug #1468508.
  
      :param hostname: The hostname to be validated.
      :returns: True if valid. False if not.
      """
      if not isinstance(hostname, str) or len(hostname) > 255:
          return False
  
      return _is_hostname_safe_re.match(hostname) is not None
  
  
  def is_valid_no_proxy(no_proxy):
      """Check no_proxy validity
  
      Check if no_proxy value that will be written to environment variable by
      ironic-python-agent is valid.
  
      :param no_proxy: the value that requires validity check. Expected to be a
          comma-separated list of host names, IP addresses and domain names
          (with optional :port).
      :returns: True if no_proxy is valid, False otherwise.
      """
      if not isinstance(no_proxy, str):
          return False
      hostname_re = re.compile('(?!-)[A-Z\\d-]{1,63}(?<!-)$', re.IGNORECASE)
      for hostname in no_proxy.split(','):
          hostname = hostname.strip().split(':')[0]
          if not hostname:
              continue
          max_length = 253
          if hostname.startswith('.'):
              # It is allowed to specify a dot in the beginning of the value to
              # indicate that it is a domain name, which means there will be at
              # least one additional character in full hostname. *. is also
              # possible but may be not supported by some clients, so is not
              # considered valid here.
              hostname = hostname[1:]
              max_length = 251
  
          if len(hostname) > max_length:
              return False
  
          if not all(hostname_re.match(part) for part in hostname.split('.')):
              return False
  
      return True
  
  
  def validate_and_normalize_mac(address):
      """Validate a MAC address and return normalized form.
  
      Checks whether the supplied MAC address is formally correct and
      normalize it to all lower case.
  
      :param address: MAC address to be validated and normalized.
      :returns: Normalized and validated MAC address.
      :raises: InvalidMAC If the MAC address is not valid.
  
      """
      if not netutils.is_valid_mac(address):
          raise exception.InvalidMAC(mac=address)
      return address.lower()
  
  
  def validate_and_normalize_datapath_id(datapath_id):
      """Validate an OpenFlow datapath_id and return normalized form.
  
      Checks whether the supplied OpenFlow datapath_id is formally correct and
      normalize it to all lower case.
  
      :param datapath_id: OpenFlow datapath_id to be validated and normalized.
      :returns: Normalized and validated OpenFlow datapath_id.
      :raises: InvalidDatapathID If an OpenFlow datapath_id is not valid.
  
      """
  
      if not is_valid_datapath_id(datapath_id):
          raise exception.InvalidDatapathID(datapath_id=datapath_id)
      return datapath_id.lower()
  
  
  def _get_hash_object(hash_algo_name):
      """Create a hash object based on given algorithm.
  
      :param hash_algo_name: name of the hashing algorithm.
      :raises: InvalidParameterValue, on unsupported or invalid input.
      :returns: a hash object based on the given named algorithm.
      """
      algorithms = hashlib.algorithms_guaranteed
      if hash_algo_name not in algorithms:
          msg = (_("Unsupported/Invalid hash name '%s' provided.")
                 % hash_algo_name)
          LOG.error(msg)
          raise exception.InvalidParameterValue(msg)
  
      return getattr(hashlib, hash_algo_name)()
  
  
  def file_has_content(path, content, hash_algo='sha256'):
      """Checks that content of the file is the same as provided reference.
  
      :param path: path to file
      :param content: reference content to check against
      :param hash_algo: hashing algo from hashlib to use, default is 'sha256'
      :returns: True if the hash of reference content is the same as
          the hash of file's content, False otherwise
      """
      file_hash_hex = fileutils.compute_file_checksum(path, algorithm=hash_algo)
      ref_hash = _get_hash_object(hash_algo)
      encoded_content = (content.encode(encoding='utf-8')
                         if isinstance(content, str) else content)
      ref_hash.update(encoded_content)
      return file_hash_hex == ref_hash.hexdigest()
  
  
  @contextlib.contextmanager
  def tempdir(**kwargs):
      tempfile.tempdir = CONF.tempdir
      tmpdir = tempfile.mkdtemp(**kwargs)
      try:
          yield tmpdir
      finally:
          try:
              shutil.rmtree(tmpdir)
          except OSError as e:
              LOG.error('Could not remove tmpdir: %s', e)
  
  
  def rmtree_without_raise(path):
      try:
          if os.path.isdir(path):
              shutil.rmtree(path)
      except OSError as e:
          LOG.warning("Failed to remove dir %(path)s, error: %(e)s",
                      {'path': path, 'e': e})
  
  
  def write_to_file(path, contents):
      with open(path, 'w') as f:
          f.write(contents)
  
  
  def create_link_without_raise(source, link):
      try:
          os.symlink(source, link)
      except OSError as e:
          if e.errno == errno.EEXIST:
              return
          else:
              LOG.warning("Failed to create symlink from "
                          "%(source)s to %(link)s, error: %(e)s",
                          {'source': source, 'link': link, 'e': e})
  
  
  def safe_rstrip(value, chars=None):
      """Removes trailing characters from a string if that does not make it empty
  
      :param value: A string value that will be stripped.
      :param chars: Characters to remove.
      :return: Stripped value.
  
      """
      if not isinstance(value, str):
          LOG.warning("Failed to remove trailing character. Returning "
                      "original object. Supplied object is not a string: "
                      "%s,", value)
          return value
  
      return value.rstrip(chars) or value
  
  
  def mount(src, dest, *args):
      """Mounts a device/image file on specified location.
  
      :param src: the path to the source file for mounting
      :param dest: the path where it needs to be mounted.
      :param args: a tuple containing the arguments to be
          passed to mount command.
      :raises: processutils.ProcessExecutionError if it failed
          to run the process.
      """
      args = ('mount', ) + args + (src, dest)
      execute(*args, run_as_root=True)
  
  
  def umount(loc, *args):
      """Umounts a mounted location.
  
      :param loc: the path to be unmounted.
      :param args: a tuple containing the arguments to be
          passed to the umount command.
      :raises: processutils.ProcessExecutionError if it failed
          to run the process.
      """
      args = ('umount', ) + args + (loc, )
      execute(*args, run_as_root=True)
  
  
  def check_dir(directory_to_check=None, required_space=1):
      """Check a directory is usable.
  
      This function can be used by drivers to check that directories
      they need to write to are usable. This should be called from the
      drivers init function. This function checks that the directory
      exists and then calls check_dir_writable and check_dir_free_space.
      If directory_to_check is not provided the default is to use the
      temp directory.
  
      :param directory_to_check: the directory to check.
      :param required_space: amount of space to check for in MiB.
      :raises: PathNotFound if directory can not be found
      :raises: DirectoryNotWritable if user is unable to write to the
               directory
      :raises InsufficientDiskSpace: if free space is < required space
      """
      # check if directory_to_check is passed in, if not set to tempdir
      if directory_to_check is None:
          directory_to_check = CONF.tempdir
  
      LOG.debug("checking directory: %s", directory_to_check)
  
      if not os.path.exists(directory_to_check):
          raise exception.PathNotFound(dir=directory_to_check)
  
      _check_dir_writable(directory_to_check)
      _check_dir_free_space(directory_to_check, required_space)
  
  
  def _check_dir_writable(chk_dir):
      """Check that the chk_dir is able to be written to.
  
      :param chk_dir: Directory to check
      :raises: DirectoryNotWritable if user is unable to write to the
               directory
      """
      is_writable = os.access(chk_dir, os.W_OK)
      if not is_writable:
          raise exception.DirectoryNotWritable(dir=chk_dir)
  
  
  def _check_dir_free_space(chk_dir, required_space=1):
      """Check that directory has some free space.
  
      :param chk_dir: Directory to check
      :param required_space: amount of space to check for in MiB.
      :raises InsufficientDiskSpace: if free space is < required space
      """
      # check that we have some free space
      stat = os.statvfs(chk_dir)
      # get dir free space in MiB.
      free_space = float(stat.f_bsize * stat.f_bavail) / 1024 / 1024
      # check for at least required_space MiB free
      if free_space < required_space:
          raise exception.InsufficientDiskSpace(path=chk_dir,
                                                required=required_space,
                                                actual=free_space)
  
  
  def get_updated_capabilities(current_capabilities, new_capabilities):
      """Returns an updated capability string.
  
      This method updates the original (or current) capabilities with the new
      capabilities. The original capabilities would typically be from a node's
      properties['capabilities']. From new_capabilities, any new capabilities
      are added, and existing capabilities may have their values updated. This
      updated capabilities string is returned.
  
      :param current_capabilities: Current capability string
      :param new_capabilities: the dictionary of capabilities to be updated.
      :returns: An updated capability string.
          with new_capabilities.
      :raises: ValueError, if current_capabilities is malformed or
          if new_capabilities is not a dictionary
      """
      if not isinstance(new_capabilities, dict):
          raise ValueError(
              _("Cannot update capabilities. The new capabilities should be in "
                "a dictionary. Provided value is %s") % new_capabilities)
  
      cap_dict = {}
      if current_capabilities:
          try:
              cap_dict = dict(x.split(':', 1)
                              for x in current_capabilities.split(','))
          except ValueError:
              # Capabilities can be filled by operator.  ValueError can
              # occur in malformed capabilities like:
              # properties/capabilities='boot_mode:bios,boot_option'.
              raise ValueError(
                  _("Invalid capabilities string '%s'.") % current_capabilities)
  
      cap_dict.update(new_capabilities)
      return ','.join('%(key)s:%(value)s' % {'key': key, 'value': value}
                      for key, value in cap_dict.items())
  
  
  def is_regex_string_in_file(path, string):
      with open(path, 'r') as inf:
          return any(re.search(string, line) for line in inf.readlines())
  
  
  def unix_file_modification_datetime(file_name):
      return timeutils.normalize_time(
          # normalize time to be UTC without timezone
          datetime.datetime.fromtimestamp(
              # fromtimestamp will return local time by default, make it UTC
              os.path.getmtime(file_name), tz=pytz.utc
          )
      )
  
  
  def validate_network_port(port, port_name="Port"):
      """Validates the given port.
  
      :param port: TCP/UDP port.
      :param port_name: Name of the port.
      :returns: An integer port number.
      :raises: InvalidParameterValue, if the port is invalid.
      """
  
      if netutils.is_valid_port(port):
          return int(port)
  
      raise exception.InvalidParameterValue(_(
          '%(port_name)s "%(port)s" is not a valid port.') %
          {'port_name': port_name, 'port': port})
  
  
  def render_template(template, params, is_file=True):
      """Renders Jinja2 template file with given parameters.
  
      :param template: full path to the Jinja2 template file
      :param params: dictionary with parameters to use when rendering
      :param is_file: whether template is file or string with template itself
      :returns: the rendered template as a string
      """
      if is_file:
          tmpl_path, tmpl_name = os.path.split(template)
          loader = jinja2.FileSystemLoader(tmpl_path)
      else:
          tmpl_name = 'template'
          loader = jinja2.DictLoader({tmpl_name: template})
      # NOTE(pas-ha) bandit does not seem to cope with such syntaxis
      # and still complains with B701 for that line
      # NOTE(pas-ha) not using default_for_string=False as we set the name
      # of the template above for strings too.
      env = jinja2.Environment(loader=loader,  # nosec B701
                               autoescape=jinja2.select_autoescape())
      tmpl = env.get_template(tmpl_name)
      return tmpl.render(params, enumerate=enumerate)
  
  
  def parse_instance_info_capabilities(node):
      """Parse the instance_info capabilities.
  
      One way of having these capabilities set is via Nova, where the
      capabilities are defined in the Flavor extra_spec and passed to
      Ironic by the Nova Ironic driver.
  
      NOTE: Although our API fully supports JSON fields, to maintain the
      backward compatibility with Juno the Nova Ironic driver is sending
      it as a string.
  
      :param node: a single Node.
      :raises: InvalidParameterValue if the capabilities string is not a
               dictionary or is malformed.
      :returns: A dictionary with the capabilities if found, otherwise an
                empty dictionary.
      """
  
      def parse_error():
          error_msg = (_('Error parsing capabilities from Node %s instance_info '
                         'field. A dictionary or a "jsonified" dictionary is '
                         'expected.') % node.uuid)
          raise exception.InvalidParameterValue(error_msg)
  
      capabilities = node.instance_info.get('capabilities', {})
      if isinstance(capabilities, str):
          try:
              capabilities = jsonutils.loads(capabilities)
          except (ValueError, TypeError):
              parse_error()
  
      if not isinstance(capabilities, dict):
          parse_error()
  
      return capabilities
  
  
  def validate_conductor_group(conductor_group):
      if not isinstance(conductor_group, str):
          raise exception.InvalidConductorGroup(group=conductor_group)
      if not re.match(r'^[a-zA-Z0-9_\-\.]*$', conductor_group):
          raise exception.InvalidConductorGroup(group=conductor_group)
  
  
  def set_node_nested_field(node, collection, field, value):
      """Set a value in a dictionary field of a node.
  
      :param node: Node object.
      :param collection: Name of the field with the dictionary.
      :param field: Nested field name.
      :param value: New value.
      """
      col = getattr(node, collection)
      col[field] = value
      setattr(node, collection, col)
  
  
  def pop_node_nested_field(node, collection, field, default=None):
      """Pop a value from a dictionary field of a node.
  
      :param node: Node object.
      :param collection: Name of the field with the dictionary.
      :param field: Nested field name.
      :param default: The default value to return.
      :return: The removed value or the default.
      """
      col = getattr(node, collection)
      result = col.pop(field, default)
      setattr(node, collection, col)
      return result
  
  
  def wrap_ipv6(ip):
      """Wrap the address in square brackets if it's an IPv6 address."""
      if ipaddress.ip_address(ip).version == 6:
          return "[%s]" % ip
      return ip
  
  
  def file_mime_type(path):
      """Gets a mime type of the given file."""
      return execute('file', '--brief', '--mime-type', path,
                     use_standard_locale=True)[0].strip()
  
  
  def _get_mb_ram_available():
      # NOTE(TheJulia): The .available value is the memory that can be given
      # to a process without this process beginning to swap itself.
      return psutil.virtual_memory().available / 1024 / 1024
  
  
  def is_memory_insufficent(raise_if_fail=False):
      """Checks available system memory and holds the deployment process.
  
      Evaluates the current system memory available, meaning can be
      allocated to a process by the kernel upon allocation request,
      and delays the execution until memory has been freed,
      or until it has timed out.
  
      This method will issue a sleep, if the amount of available memory is
      insufficent. This is configured using the
      ``[DEFAULT]minimum_memory_wait_time`` and the
      ``[DEFAULT]minimum_memory_wait_retries``.
  
      :param raise_if_fail: Default False, but if set to true an
                            InsufficentMemory exception is raised
                            upon insufficent memory.
      :returns: True if the check has timed out. Otherwise None is returned.
      :raises: InsufficentMemory if the raise_if_fail parameter is set to
               True.
      """
      required_memory = CONF.minimum_required_memory
      loop_count = 0
  
      while _get_mb_ram_available() < required_memory:
          log_values = {
              'available': _get_mb_ram_available(),
              'required': required_memory,
          }
          if CONF.minimum_memory_warning_only:
              LOG.warning('Memory is at %(available)s MiB, required is '
                          '%(required)s. Ironic is in warning-only mode '
                          'which can be changed by altering the '
                          '[DEFAULT]minimum_memory_warning_only',
                          log_values)
              return False
          if loop_count >= CONF.minimum_memory_wait_retries:
              LOG.error('Memory is at %(available)s MiB, required is '
                        '%(required)s. Notifying caller that we have '
                        'exceeded retries.',
                        log_values)
              if raise_if_fail:
                  raise exception.InsufficentMemory(
                      free=_get_mb_ram_available(),
                      required=required_memory)
              return True
          LOG.warning('Memory is at %(available)s MiB, required is '
                      '%(required)s, waiting.', log_values)
          # Sleep so interpreter can switch threads.
          time.sleep(CONF.minimum_memory_wait_time)
          loop_count = loop_count + 1
  