text: # (c) 2012-2014, Michael DeHaan <michael.dehaan@gmail.com>
  #
  # This file is part of Ansible
  #
  # Ansible is free software: you can redistribute it and/or modify
  # it under the terms of the GNU General Public License as published by
  # the Free Software Foundation, either version 3 of the License, or
  # (at your option) any later version.
  #
  # Ansible is distributed in the hope that it will be useful,
  # but WITHOUT ANY WARRANTY; without even the implied warranty of
  # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  # GNU General Public License for more details.
  #
  # You should have received a copy of the GNU General Public License
  # along with Ansible.  If not, see <http://www.gnu.org/licenses/>.
  
  # Make coding more python3-ish
  from __future__ import (absolute_import, division, print_function)
  __metaclass__ = type
  
  import os
  import sys
  
  from collections import defaultdict, MutableMapping
  
  from ansible.compat.six import iteritems
  from jinja2.exceptions import UndefinedError
  
  try:
      from hashlib import sha1
  except ImportError:
      from sha import sha as sha1
  
  from ansible import constants as C
  from ansible.cli import CLI
  from ansible.compat.six import string_types, text_type
  from ansible.errors import AnsibleError, AnsibleParserError, AnsibleUndefinedVariable, AnsibleFileNotFound
  from ansible.inventory.host import Host
  from ansible.plugins import lookup_loader
  from ansible.plugins.cache import FactCache
  from ansible.template import Templar
  from ansible.utils.listify import listify_lookup_plugin_terms
  from ansible.utils.vars import combine_vars
  from ansible.vars.unsafe_proxy import wrap_var
  from ansible.module_utils._text import to_native
  
  try:
      from __main__ import display
  except ImportError:
      from ansible.utils.display import Display
      display = Display()
  
  VARIABLE_CACHE = dict()
  HOSTVARS_CACHE = dict()
  
  class AnsibleInventoryVarsData(dict):
      def __init__(self, *args, **kwargs):
          super(AnsibleInventoryVarsData, self).__init__(*args, **kwargs)
          self.path = None
  
  def preprocess_vars(a):
      '''
      Ensures that vars contained in the parameter passed in are
      returned as a list of dictionaries, to ensure for instance
      that vars loaded from a file conform to an expected state.
      '''
  
      if a is None:
          return None
      elif not isinstance(a, list):
          data = [ a ]
      else:
          data = a
  
      for item in data:
          if not isinstance(item, MutableMapping):
              raise AnsibleError("variable files must contain either a dictionary of variables, or a list of dictionaries. Got: %s (%s)" % (a, type(a)))
  
      return data
  
  def strip_internal_keys(dirty):
      '''
      All keys stating with _ansible_ are internal, so create a copy of the 'dirty' dict
      and remove them from the clean one before returning it
      '''
      clean = dirty.copy()
      for k in dirty.keys():
          if isinstance(k, string_types) and k.startswith('_ansible_'):
              del clean[k]
          elif isinstance(dirty[k], dict):
              clean[k] = strip_internal_keys(dirty[k])
      return clean
  
  
  class VariableManager:
  
      def __init__(self):
  
          self._nonpersistent_fact_cache = defaultdict(dict)
          self._vars_cache = defaultdict(dict)
          self._extra_vars = defaultdict(dict)
          self._host_vars_files = defaultdict(dict)
          self._group_vars_files = defaultdict(dict)
          self._inventory = None
          self._hostvars = None
          self._omit_token = '__omit_place_holder__%s' % sha1(os.urandom(64)).hexdigest()
          self._options_vars = defaultdict(dict)
  
          # bad cache plugin is not fatal error
          try:
              self._fact_cache = FactCache()
          except AnsibleError as e:
              display.warning(to_native(e))
              # fallback to a dict as in memory cache
              self._fact_cache = {}
  
      def __getstate__(self):
          data = dict(
              fact_cache = self._fact_cache,
              np_fact_cache = self._nonpersistent_fact_cache,
              vars_cache = self._vars_cache,
              extra_vars = self._extra_vars,
              host_vars_files = self._host_vars_files,
              group_vars_files = self._group_vars_files,
              omit_token = self._omit_token,
              options_vars = self._options_vars,
              #inventory = self._inventory,
          )
          return data
  
      def __setstate__(self, data):
          self._fact_cache = data.get('fact_cache', defaultdict(dict))
          self._nonpersistent_fact_cache = data.get('np_fact_cache', defaultdict(dict))
          self._vars_cache = data.get('vars_cache', defaultdict(dict))
          self._extra_vars = data.get('extra_vars', dict())
          self._host_vars_files = data.get('host_vars_files', defaultdict(dict))
          self._group_vars_files = data.get('group_vars_files', defaultdict(dict))
          self._omit_token = data.get('omit_token', '__omit_place_holder__%s' % sha1(os.urandom(64)).hexdigest())
          self._inventory = data.get('inventory', None)
          self._options_vars = data.get('options_vars', dict())
  
      def _get_cache_entry(self, play=None, host=None, task=None):
          play_id = "NONE"
          if play:
              play_id = play._uuid
  
          host_id = "NONE"
          if host:
              host_id = host.get_name()
  
          task_id = "NONE"
          if task:
              task_id = task._uuid
  
          return "PLAY:%s;HOST:%s;TASK:%s" % (play_id, host_id, task_id)
  
      @property
      def extra_vars(self):
          ''' ensures a clean copy of the extra_vars are made '''
          return self._extra_vars.copy()
  
      @extra_vars.setter
      def extra_vars(self, value):
          ''' ensures a clean copy of the extra_vars are used to set the value '''
          assert isinstance(value, MutableMapping)
          self._extra_vars = value.copy()
  
      def set_inventory(self, inventory):
          self._inventory = inventory
  
      @property
      def options_vars(self):
          ''' ensures a clean copy of the options_vars are made '''
          return self._options_vars.copy()
  
      @options_vars.setter
      def options_vars(self, value):
          ''' ensures a clean copy of the options_vars are used to set the value '''
          assert isinstance(value, dict)
          self._options_vars = value.copy()
  
      def _preprocess_vars(self, a):
          '''
          Ensures that vars contained in the parameter passed in are
          returned as a list of dictionaries, to ensure for instance
          that vars loaded from a file conform to an expected state.
          '''
  
          if a is None:
              return None
          elif not isinstance(a, list):
              data = [ a ]
          else:
              data = a
  
          for item in data:
              if not isinstance(item, MutableMapping):
                  raise AnsibleError("variable files must contain either a dictionary of variables, or a list of dictionaries. Got: %s (%s)" % (a, type(a)))
  
          return data
  
      def get_vars(self, loader, play=None, host=None, task=None, include_hostvars=True, include_delegate_to=True, use_cache=True):
          '''
          Returns the variables, with optional "context" given via the parameters
          for the play, host, and task (which could possibly result in different
          sets of variables being returned due to the additional context).
  
          The order of precedence is:
          - play->roles->get_default_vars (if there is a play context)
          - group_vars_files[host] (if there is a host context)
          - host_vars_files[host] (if there is a host context)
          - host->get_vars (if there is a host context)
          - fact_cache[host] (if there is a host context)
          - play vars (if there is a play context)
          - play vars_files (if there's no host context, ignore
            file names that cannot be templated)
          - task->get_vars (if there is a task context)
          - vars_cache[host] (if there is a host context)
          - extra vars
          '''
  
          display.debug("in VariableManager get_vars()")
          cache_entry = self._get_cache_entry(play=play, host=host, task=task)
          if cache_entry in VARIABLE_CACHE and use_cache:
              display.debug("vars are cached, returning them now")
              return VARIABLE_CACHE[cache_entry]
  
          all_vars = dict()
          magic_variables = self._get_magic_variables(
              loader=loader,
              play=play,
              host=host,
              task=task,
              include_hostvars=include_hostvars,
              include_delegate_to=include_delegate_to,
          )
  
          if play:
              # first we compile any vars specified in defaults/main.yml
              # for all roles within the specified play
              for role in play.get_roles():
                  all_vars = combine_vars(all_vars, role.get_default_vars())
  
          # if we have a task in this context, and that task has a role, make
          # sure it sees its defaults above any other roles, as we previously
          # (v1) made sure each task had a copy of its roles default vars
          if task and task._role is not None and (play or task.action == 'include_role'):
              all_vars = combine_vars(all_vars, task._role.get_default_vars(dep_chain=task.get_dep_chain()))
  
          if host:
              # first we merge in vars from groups specified in the inventory (INI or script)
              all_vars = combine_vars(all_vars, host.get_group_vars())
  
              # next, we load any vars from group_vars files and then any vars from host_vars
              # files which may apply to this host or the groups it belongs to. We merge in the
              # special 'all' group_vars first, if they exist
              if 'all' in self._group_vars_files:
                  data = preprocess_vars(self._group_vars_files['all'])
                  for item in data:
                      all_vars = combine_vars(all_vars, item)
  
              for group in sorted(host.get_groups(), key=lambda g: (g.depth, g.name)):
                  if group.name in self._group_vars_files and group.name != 'all':
                      for data in self._group_vars_files[group.name]:
                          data = preprocess_vars(data)
                          for item in data:
                              all_vars = combine_vars(all_vars, item)
  
              # then we merge in vars from the host specified in the inventory (INI or script)
              all_vars = combine_vars(all_vars, host.get_vars())
  
              # then we merge in the host_vars/<hostname> file, if it exists
              host_name = host.get_name()
              if host_name in self._host_vars_files:
                  for data in self._host_vars_files[host_name]:
                      data = preprocess_vars(data)
                      for item in data:
                          all_vars = combine_vars(all_vars, item)
  
              # finally, the facts caches for this host, if it exists
              try:
                  host_facts = wrap_var(self._fact_cache.get(host.name, dict()))
                  all_vars = combine_vars(all_vars, host_facts)
              except KeyError:
                  pass
  
          if play:
              all_vars = combine_vars(all_vars, play.get_vars())
  
              for vars_file_item in play.get_vars_files():
                  # create a set of temporary vars here, which incorporate the extra
                  # and magic vars so we can properly template the vars_files entries
                  temp_vars = combine_vars(all_vars, self._extra_vars)
                  temp_vars = combine_vars(temp_vars, magic_variables)
                  templar = Templar(loader=loader, variables=temp_vars)
  
                  # we assume each item in the list is itself a list, as we
                  # support "conditional includes" for vars_files, which mimics
                  # the with_first_found mechanism.
                  vars_file_list = vars_file_item
                  if not isinstance(vars_file_list, list):
                      vars_file_list = [ vars_file_list ]
  
                  # now we iterate through the (potential) files, and break out
                  # as soon as we read one from the list. If none are found, we
                  # raise an error, which is silently ignored at this point.
                  try:
                      for vars_file in vars_file_list:
                          vars_file = templar.template(vars_file)
                          try:
                              data = preprocess_vars(loader.load_from_file(vars_file))
                              if data is not None:
                                  for item in data:
                                      all_vars = combine_vars(all_vars, item)
                              break
                          except AnsibleFileNotFound:
                              # we continue on loader failures
                              continue
                          except AnsibleParserError:
                              raise
                      else:
                          # if include_delegate_to is set to False, we ignore the missing
                          # vars file here because we're working on a delegated host
                          if include_delegate_to:
                              raise AnsibleFileNotFound("vars file %s was not found" % vars_file_item)
                  except (UndefinedError, AnsibleUndefinedVariable):
                      if host is not None and self._fact_cache.get(host.name, dict()).get('module_setup') and task is not None:
                          raise AnsibleUndefinedVariable("an undefined variable was found when attempting to template the vars_files item '%s'" % vars_file_item, obj=vars_file_item)
                      else:
                          # we do not have a full context here, and the missing variable could be
                          # because of that, so just show a warning and continue
                          display.vvv("skipping vars_file '%s' due to an undefined variable" % vars_file_item)
                          continue
  
              # By default, we now merge in all vars from all roles in the play,
              # unless the user has disabled this via a config option
              if not C.DEFAULT_PRIVATE_ROLE_VARS:
                  for role in play.get_roles():
                      all_vars = combine_vars(all_vars, role.get_vars(include_params=False))
  
          # next, we merge in the vars from the role, which will specifically
          # follow the role dependency chain, and then we merge in the tasks
          # vars (which will look at parent blocks/task includes)
          if task:
              if task._role:
                  all_vars = combine_vars(all_vars, task._role.get_vars(task.get_dep_chain(), include_params=False))
              all_vars = combine_vars(all_vars, task.get_vars())
  
          # next, we merge in the vars cache (include vars) and nonpersistent
          # facts cache (set_fact/register), in that order
          if host:
              all_vars = combine_vars(all_vars, self._vars_cache.get(host.get_name(), dict()))
              all_vars = combine_vars(all_vars, self._nonpersistent_fact_cache.get(host.name, dict()))
  
          # next, we merge in role params and task include params
          if task:
              if task._role:
                  all_vars = combine_vars(all_vars, task._role.get_role_params(task.get_dep_chain()))
  
              # special case for include tasks, where the include params
              # may be specified in the vars field for the task, which should
              # have higher precedence than the vars/np facts above
              all_vars = combine_vars(all_vars, task.get_include_params())
  
          # finally, we merge in extra vars and the magic variables
          all_vars = combine_vars(all_vars, self._extra_vars)
          all_vars = combine_vars(all_vars, magic_variables)
  
          # special case for the 'environment' magic variable, as someone
          # may have set it as a variable and we don't want to stomp on it
          if task:
              if 'environment' not in all_vars:
                  all_vars['environment'] = task.environment
              else:
                  display.warning("The variable 'environment' appears to be used already, which is also used internally for environment variables set on the task/block/play. You should use a different variable name to avoid conflicts with this internal variable")
  
          # if we have a task and we're delegating to another host, figure out the
          # variables for that host now so we don't have to rely on hostvars later
          if task and task.delegate_to is not None and include_delegate_to:
              all_vars['ansible_delegated_vars'] = self._get_delegated_vars(loader, play, task, all_vars)
  
          #VARIABLE_CACHE[cache_entry] = all_vars
          if task or play:
              all_vars['vars'] = all_vars.copy()
  
          display.debug("done with get_vars()")
          return all_vars
  
      def invalidate_hostvars_cache(self, play):
          hostvars_cache_entry = self._get_cache_entry(play=play)
          if hostvars_cache_entry in HOSTVARS_CACHE:
              del HOSTVARS_CACHE[hostvars_cache_entry]
  
      def _get_magic_variables(self, loader, play, host, task, include_hostvars, include_delegate_to):
          '''
          Returns a dictionary of so-called "magic" variables in Ansible,
          which are special variables we set internally for use.
          '''
  
          variables = dict()
          variables['playbook_dir'] = loader.get_basedir()
          variables['ansible_playbook_python'] = sys.executable
  
          if host:
              # host already provides some magic vars via host.get_vars()
              if self._inventory:
                  variables['groups']  = self._inventory.get_group_dict()
  
          if play:
              variables['role_names'] = [r._role_name for r in play.roles]
  
          if task:
              if task._role:
                  variables['role_name'] = task._role.get_name()
                  variables['role_path'] = task._role._role_path
                  variables['role_uuid'] = text_type(task._role._uuid)
  
          if self._inventory is not None:
              variables['inventory_dir'] = self._inventory.basedir()
              variables['inventory_file'] = self._inventory.src()
              if play:
                  templar = Templar(loader=loader)
                  if templar.is_template(play.hosts):
                      pattern = 'all'
                  else:
                      pattern = play.hosts or 'all'
                  # add the list of hosts in the play, as adjusted for limit/filters
                  variables['ansible_play_hosts_all'] = [x.name for x in self._inventory.get_hosts(pattern=pattern, ignore_restrictions=True)]
                  variables['ansible_play_hosts'] = [x for x in variables['ansible_play_hosts_all'] if x not in play._removed_hosts]
                  variables['ansible_play_batch'] = [x.name for x in self._inventory.get_hosts() if x.name not in play._removed_hosts]
  
                  #DEPRECATED: play_hosts should be deprecated in favor of ansible_play_batch,
                  #  however this would take work in the templating engine, so for now we'll add both
                  variables['play_hosts'] = variables['ansible_play_batch']
  
          # the 'omit' value alows params to be left out if the variable they are based on is undefined
          variables['omit'] = self._omit_token
          variables['ansible_version'] = CLI.version_info(gitinfo=False)
          # Set options vars
          for option, option_value in iteritems(self._options_vars):
              variables[option] = option_value
  
          if self._hostvars is not None and include_hostvars:
              variables['hostvars'] = self._hostvars
  
          return variables
  
      def _get_delegated_vars(self, loader, play, task, existing_variables):
          # we unfortunately need to template the delegate_to field here,
          # as we're fetching vars before post_validate has been called on
          # the task that has been passed in
          vars_copy = existing_variables.copy()
          templar = Templar(loader=loader, variables=vars_copy)
  
          items = []
          if task.loop is not None:
              if task.loop in lookup_loader:
                  try:
                      loop_terms = listify_lookup_plugin_terms(terms=task.loop_args, templar=templar, loader=loader, fail_on_undefined=True, convert_bare=False)
                      items = lookup_loader.get(task.loop, loader=loader, templar=templar).run(terms=loop_terms, variables=vars_copy)
                  except AnsibleUndefinedVariable:
                      # This task will be skipped later due to this, so we just setup
                      # a dummy array for the later code so it doesn't fail
                      items = [None]
              else:
                  raise AnsibleError("Unexpected failure in finding the lookup named '%s' in the available lookup plugins" % task.loop)
          else:
              items = [None]
  
          delegated_host_vars = dict()
          for item in items:
              # update the variables with the item value for templating, in case we need it
              if item is not None:
                  vars_copy['item'] = item
  
              templar.set_available_variables(vars_copy)
              delegated_host_name = templar.template(task.delegate_to, fail_on_undefined=False)
              if delegated_host_name is None:
                  raise AnsibleError(message="Undefined delegate_to host for task:", obj=task._ds)
              if delegated_host_name in delegated_host_vars:
                  # no need to repeat ourselves, as the delegate_to value
                  # does not appear to be tied to the loop item variable
                  continue
  
              # a dictionary of variables to use if we have to create a new host below
              # we set the default port based on the default transport here, to make sure
              # we use the proper default for windows
              new_port = C.DEFAULT_REMOTE_PORT
              if C.DEFAULT_TRANSPORT == 'winrm':
                  new_port = 5986
  
              new_delegated_host_vars = dict(
                  ansible_delegated_host=delegated_host_name,
                  ansible_host=delegated_host_name,
                  ansible_port=new_port,
                  ansible_user=C.DEFAULT_REMOTE_USER,
                  ansible_connection=C.DEFAULT_TRANSPORT,
              )
  
              # now try to find the delegated-to host in inventory, or failing that,
              # create a new host on the fly so we can fetch variables for it
              delegated_host = None
              if self._inventory is not None:
                  delegated_host = self._inventory.get_host(delegated_host_name)
                  # try looking it up based on the address field, and finally
                  # fall back to creating a host on the fly to use for the var lookup
                  if delegated_host is None:
                      if delegated_host_name in C.LOCALHOST:
                          delegated_host = self._inventory.localhost
                      else:
                          for h in self._inventory.get_hosts(ignore_limits=True, ignore_restrictions=True):
                              # check if the address matches, or if both the delegated_to host
                              # and the current host are in the list of localhost aliases
                              if h.address == delegated_host_name:
                                  delegated_host = h
                                  break
                          else:
                              delegated_host = Host(name=delegated_host_name)
                              delegated_host.vars.update(new_delegated_host_vars)
              else:
                  delegated_host = Host(name=delegated_host_name)
                  delegated_host.vars.update(new_delegated_host_vars)
  
              # now we go fetch the vars for the delegated-to host and save them in our
              # master dictionary of variables to be used later in the TaskExecutor/PlayContext
              delegated_host_vars[delegated_host_name] = self.get_vars(
                  loader=loader,
                  play=play,
                  host=delegated_host,
                  task=task,
                  include_delegate_to=False,
                  include_hostvars=False,
              )
  
          return delegated_host_vars
  
      def _get_inventory_basename(self, path):
          '''
          Returns the basename minus the extension of the given path, so the
          bare filename can be matched against host/group names later
          '''
  
          (name, ext) = os.path.splitext(os.path.basename(path))
          if ext not in ('.yml', '.yaml'):
              return os.path.basename(path)
          else:
              return name
  
      def _load_inventory_file(self, path, loader, filter_ext=False):
          '''
          helper function, which loads the file and gets the
          basename of the file without the extension
          '''
  
          if loader.is_directory(path):
              data = dict()
  
              try:
                  names = loader.list_directory(path)
              except os.error as err:
                  raise AnsibleError("This folder cannot be listed: %s: %s." % (path, err.strerror))
  
              # evaluate files in a stable order rather than whatever
              # order the filesystem lists them.
              names.sort()
  
              # do not parse hidden files or dirs, e.g. .svn/
              paths = [os.path.join(path, name) for name in names if not (name.startswith('.') or name.endswith('~'))]
              for p in paths:
                  results = self._load_inventory_file(path=p, loader=loader, filter_ext=True)
                  if results is not None:
                      data = combine_vars(data, results)
  
          else:
              file_name, ext = os.path.splitext(path)
              data = None
              if not filter_ext or ext in C.YAML_FILENAME_EXTENSIONS:
                  if loader.path_exists(path):
                      data = loader.load_from_file(path)
                  else:
                      # try appending yaml extenstion to find valid files
                      # avoid empty extensions otherwise all files would be tried
                      for test_ext in (ext for ext in C.YAML_FILENAME_EXTENSIONS if ext):
                          new_path = path + test_ext
                          if loader.path_exists(new_path):
                              data = loader.load_from_file(new_path)
                              break
  
          rval = AnsibleInventoryVarsData()
          rval.path = path
  
          if data is not None:
              if not isinstance(data, dict):
                  raise AnsibleError("Problem parsing file '%s': line %d, column %d" % data.ansible_pos)
              else:
                  rval.update(data)
  
          return rval
  
      def add_host_vars_file(self, path, loader):
          '''
          Loads and caches a host_vars file in the _host_vars_files dict,
          where the key to that dictionary is the basename of the file, minus
          the extension, for matching against a given inventory host name
          '''
  
          name = self._get_inventory_basename(path)
          if name not in self._host_vars_files:
              self._host_vars_files[name] = []
  
          for entry in self._host_vars_files[name]:
              if entry.path == path:
                  data = entry
                  break
          else:
              data = self._load_inventory_file(path, loader)
              if data:
                  self._host_vars_files[name].append(data)
  
          return data
  
  
      def add_group_vars_file(self, path, loader):
          '''
          Loads and caches a host_vars file in the _host_vars_files dict,
          where the key to that dictionary is the basename of the file, minus
          the extension, for matching against a given inventory host name
          '''
  
          name = self._get_inventory_basename(path)
          if name not in self._group_vars_files:
              self._group_vars_files[name] = []
  
          for entry in self._group_vars_files[name]:
              if entry.path == path:
                  data = entry
                  break
          else:
              data = self._load_inventory_file(path, loader)
              if data:
                  self._group_vars_files[name].append(data)
  
          return data
  
      def clear_playbook_hostgroup_vars_files(self, path):
          for f in self._host_vars_files.keys():
              keepers = []
              for entry in self._host_vars_files[f]:
                  if os.path.dirname(entry.path) != os.path.join(path, 'host_vars'):
                      keepers.append(entry)
              self._host_vars_files[f] = keepers
          for f in self._group_vars_files.keys():
              keepers = []
              for entry in self._group_vars_files[f]:
                  if os.path.dirname(entry.path) != os.path.join(path, 'group_vars'):
                      keepers.append(entry)
              self._group_vars_files[f] = keepers
  
      def clear_facts(self, hostname):
          '''
          Clears the facts for a host
          '''
          if hostname in self._fact_cache:
              del self._fact_cache[hostname]
  
      def set_host_facts(self, host, facts):
          '''
          Sets or updates the given facts for a host in the fact cache.
          '''
  
          assert isinstance(facts, dict)
  
          if host.name not in self._fact_cache:
              self._fact_cache[host.name] = facts
          else:
              try:
                  self._fact_cache.update(host.name, facts)
              except KeyError:
                  self._fact_cache[host.name] = facts
  
      def set_nonpersistent_facts(self, host, facts):
          '''
          Sets or updates the given facts for a host in the fact cache.
          '''
  
          assert isinstance(facts, dict)
  
          if host.name not in self._nonpersistent_fact_cache:
              self._nonpersistent_fact_cache[host.name] = facts
          else:
              try:
                  self._nonpersistent_fact_cache[host.name].update(facts)
              except KeyError:
                  self._nonpersistent_fact_cache[host.name] = facts
  
      def set_host_variable(self, host, varname, value):
          '''
          Sets a value in the vars_cache for a host.
          '''
          host_name = host.get_name()
          if host_name not in self._vars_cache:
              self._vars_cache[host_name] = dict()
          if varname in self._vars_cache[host_name] and isinstance(self._vars_cache[host_name][varname], MutableMapping) and isinstance(value, MutableMapping):
              self._vars_cache[host_name] = combine_vars(self._vars_cache[host_name], {varname: value})
          else:
              self._vars_cache[host_name][varname] = value
  