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Edit File: manager.py
# (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 from collections.abc import Mapping, MutableMapping, Sequence from hashlib import sha1 from jinja2.exceptions import UndefinedError from ansible import constants as C from ansible.errors import AnsibleError, AnsibleParserError, AnsibleUndefinedVariable, AnsibleFileNotFound, AnsibleAssertionError, AnsibleTemplateError from ansible.inventory.host import Host from ansible.inventory.helpers import sort_groups, get_group_vars from ansible.module_utils._text import to_text from ansible.module_utils.six import text_type, string_types from ansible.plugins.loader import lookup_loader from ansible.vars.fact_cache import FactCache from ansible.template import Templar from ansible.utils.display import Display from ansible.utils.listify import listify_lookup_plugin_terms from ansible.utils.vars import combine_vars, load_extra_vars, load_options_vars from ansible.utils.unsafe_proxy import wrap_var from ansible.vars.clean import namespace_facts, clean_facts from ansible.vars.plugins import get_vars_from_inventory_sources, get_vars_from_path display = Display() 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 class VariableManager: _ALLOWED = frozenset(['plugins_by_group', 'groups_plugins_play', 'groups_plugins_inventory', 'groups_inventory', 'all_plugins_play', 'all_plugins_inventory', 'all_inventory']) def __init__(self, loader=None, inventory=None, version_info=None): 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 = inventory self._loader = loader self._hostvars = None self._omit_token = '__omit_place_holder__%s' % sha1(os.urandom(64)).hexdigest() self._options_vars = load_options_vars(version_info) # If the basedir is specified as the empty string then it results in cwd being used. # This is not a safe location to load vars from. basedir = self._options_vars.get('basedir', False) self.safe_basedir = bool(basedir is False or basedir) # load extra vars self._extra_vars = load_extra_vars(loader=self._loader) # load fact cache try: self._fact_cache = FactCache() except AnsibleError as e: # bad cache plugin is not fatal error # fallback to a dict as in memory cache display.warning(to_text(e)) 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, safe_basedir=self.safe_basedir, ) 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()) self.safe_basedir = data.get('safe_basedir', False) self._loader = None self._hostvars = None @property def extra_vars(self): return self._extra_vars def set_inventory(self, inventory): self._inventory = inventory def get_vars(self, play=None, host=None, task=None, include_hostvars=True, include_delegate_to=True, use_cache=True, _hosts=None, _hosts_all=None, stage='task'): ''' 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 ``_hosts`` and ``_hosts_all`` should be considered private args, with only internal trusted callers relying on the functionality they provide. These arguments may be removed at a later date without a deprecation period and without warning. ''' display.debug("in VariableManager get_vars()") all_vars = dict() magic_variables = self._get_magic_variables( play=play, host=host, task=task, include_hostvars=include_hostvars, include_delegate_to=include_delegate_to, _hosts=_hosts, _hosts_all=_hosts_all, ) _vars_sources = {} def _combine_and_track(data, new_data, source): ''' Wrapper function to update var sources dict and call combine_vars() See notes in the VarsWithSources docstring for caveats and limitations of the source tracking ''' if C.DEFAULT_DEBUG: # Populate var sources dict for key in new_data: _vars_sources[key] = source return combine_vars(data, new_data) # default for all cases basedirs = [] if self.safe_basedir: # avoid adhoc/console loading cwd basedirs = [self._loader.get_basedir()] 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_and_track(all_vars, role.get_default_vars(), "role '%s' defaults" % role.name) if task: # set basedirs if C.PLAYBOOK_VARS_ROOT == 'all': # should be default basedirs = task.get_search_path() elif C.PLAYBOOK_VARS_ROOT in ('bottom', 'playbook_dir'): # only option in 2.4.0 basedirs = [task.get_search_path()[0]] elif C.PLAYBOOK_VARS_ROOT != 'top': # preserves default basedirs, only option pre 2.3 raise AnsibleError('Unknown playbook vars logic: %s' % C.PLAYBOOK_VARS_ROOT) # 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._role is not None and (play or task.action in C._ACTION_INCLUDE_ROLE): all_vars = _combine_and_track(all_vars, task._role.get_default_vars(dep_chain=task.get_dep_chain()), "role '%s' defaults" % task._role.name) if host: # THE 'all' group and the rest of groups for a host, used below all_group = self._inventory.groups.get('all') host_groups = sort_groups([g for g in host.get_groups() if g.name not in ['all']]) def _get_plugin_vars(plugin, path, entities): data = {} try: data = plugin.get_vars(self._loader, path, entities) except AttributeError: try: for entity in entities: if isinstance(entity, Host): data |= plugin.get_host_vars(entity.name) else: data |= plugin.get_group_vars(entity.name) except AttributeError: if hasattr(plugin, 'run'): raise AnsibleError("Cannot use v1 type vars plugin %s from %s" % (plugin._load_name, plugin._original_path)) else: raise AnsibleError("Invalid vars plugin %s from %s" % (plugin._load_name, plugin._original_path)) return data # internal functions that actually do the work def _plugins_inventory(entities): ''' merges all entities by inventory source ''' return get_vars_from_inventory_sources(self._loader, self._inventory._sources, entities, stage) def _plugins_play(entities): ''' merges all entities adjacent to play ''' data = {} for path in basedirs: data = _combine_and_track(data, get_vars_from_path(self._loader, path, entities, stage), "path '%s'" % path) return data # configurable functions that are sortable via config, remember to add to _ALLOWED if expanding this list def all_inventory(): return all_group.get_vars() def all_plugins_inventory(): return _plugins_inventory([all_group]) def all_plugins_play(): return _plugins_play([all_group]) def groups_inventory(): ''' gets group vars from inventory ''' return get_group_vars(host_groups) def groups_plugins_inventory(): ''' gets plugin sources from inventory for groups ''' return _plugins_inventory(host_groups) def groups_plugins_play(): ''' gets plugin sources from play for groups ''' return _plugins_play(host_groups) def plugins_by_groups(): ''' merges all plugin sources by group, This should be used instead, NOT in combination with the other groups_plugins* functions ''' data = {} for group in host_groups: data[group] = _combine_and_track(data[group], _plugins_inventory(group), "inventory group_vars for '%s'" % group) data[group] = _combine_and_track(data[group], _plugins_play(group), "playbook group_vars for '%s'" % group) return data # Merge groups as per precedence config # only allow to call the functions we want exposed for entry in C.VARIABLE_PRECEDENCE: if entry in self._ALLOWED: display.debug('Calling %s to load vars for %s' % (entry, host.name)) all_vars = _combine_and_track(all_vars, locals()[entry](), "group vars, precedence entry '%s'" % entry) else: display.warning('Ignoring unknown variable precedence entry: %s' % (entry)) # host vars, from inventory, inventory adjacent and play adjacent via plugins all_vars = _combine_and_track(all_vars, host.get_vars(), "host vars for '%s'" % host) all_vars = _combine_and_track(all_vars, _plugins_inventory([host]), "inventory host_vars for '%s'" % host) all_vars = _combine_and_track(all_vars, _plugins_play([host]), "playbook host_vars for '%s'" % host) # finally, the facts caches for this host, if it exists # TODO: cleaning of facts should eventually become part of taskresults instead of vars try: facts = wrap_var(self._fact_cache.get(host.name, {})) all_vars |= namespace_facts(facts) # push facts to main namespace if C.INJECT_FACTS_AS_VARS: all_vars = _combine_and_track(all_vars, wrap_var(clean_facts(facts)), "facts") else: # always 'promote' ansible_local all_vars = _combine_and_track(all_vars, wrap_var({'ansible_local': facts.get('ansible_local', {})}), "facts") except KeyError: pass if play: all_vars = _combine_and_track(all_vars, play.get_vars(), "play vars") vars_files = play.get_vars_files() try: for vars_file_item in 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 # NOTE: this makes them depend on host vars/facts so things like # ansible_facts['os_distribution'] can be used, ala include_vars. # Consider DEPRECATING this in the future, since we have include_vars ... temp_vars = combine_vars(all_vars, self._extra_vars) temp_vars = combine_vars(temp_vars, magic_variables) templar = Templar(loader=self._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) if not (isinstance(vars_file, Sequence)): raise AnsibleError( "Invalid vars_files entry found: %r\n" "vars_files entries should be either a string type or " "a list of string types after template expansion" % vars_file ) try: play_search_stack = play.get_search_path() found_file = real_file = self._loader.path_dwim_relative_stack(play_search_stack, 'vars', vars_file) data = preprocess_vars(self._loader.load_from_file(found_file, unsafe=True, cache=False)) if data is not None: for item in data: all_vars = _combine_and_track(all_vars, item, "play vars_files from '%s'" % vars_file) break except AnsibleFileNotFound: # we continue on loader failures continue except AnsibleParserError: raise else: # if include_delegate_to is set to False or we don't have a host, we ignore the missing # vars file here because we're working on a delegated host or require host vars, see NOTE above if include_delegate_to and host: 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 display.vvv("Read vars_file '%s'" % vars_file_item) except TypeError: raise AnsibleParserError("Error while reading vars files - please supply a list of file names. " "Got '%s' of type %s" % (vars_files, type(vars_files))) # 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_and_track(all_vars, role.get_vars(include_params=False), "role '%s' vars" % role.name) # 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_and_track(all_vars, task._role.get_vars(task.get_dep_chain(), include_params=False), "role '%s' vars" % task._role.name) all_vars = _combine_and_track(all_vars, task.get_vars(), "task vars") # next, we merge in the vars cache (include vars) and nonpersistent # facts cache (set_fact/register), in that order if host: # include_vars non-persistent cache all_vars = _combine_and_track(all_vars, self._vars_cache.get(host.get_name(), dict()), "include_vars") # fact non-persistent cache all_vars = _combine_and_track(all_vars, self._nonpersistent_fact_cache.get(host.name, dict()), "set_fact") # next, we merge in role params and task include params if task: if task._role: all_vars = _combine_and_track(all_vars, task._role.get_role_params(task.get_dep_chain()), "role '%s' params" % task._role.name) # 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_and_track(all_vars, task.get_include_params(), "include params") # extra vars all_vars = _combine_and_track(all_vars, self._extra_vars, "extra vars") # magic variables all_vars = _combine_and_track(all_vars, magic_variables, "magic vars") # 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: all_vars['environment'] = task.environment # 'vars' magic var if task or play: # has to be copy, otherwise recursive ref all_vars['vars'] = all_vars.copy() # if we have a host and task and we're delegating to another host, # figure out the variables for that host now so we don't have to rely on host vars later if task and host and task.delegate_to is not None and include_delegate_to: all_vars['ansible_delegated_vars'], all_vars['_ansible_loop_cache'] = self._get_delegated_vars(play, task, all_vars) display.debug("done with get_vars()") if C.DEFAULT_DEBUG: # Use VarsWithSources wrapper class to display var sources return VarsWithSources.new_vars_with_sources(all_vars, _vars_sources) else: return all_vars def _get_magic_variables(self, play, host, task, include_hostvars, include_delegate_to, _hosts=None, _hosts_all=None): ''' Returns a dictionary of so-called "magic" variables in Ansible, which are special variables we set internally for use. ''' variables = {} variables['playbook_dir'] = os.path.abspath(self._loader.get_basedir()) variables['ansible_playbook_python'] = sys.executable variables['ansible_config_file'] = C.CONFIG_FILE if play: # This is a list of all role names of all dependencies for all roles for this play dependency_role_names = list({d.get_name() for r in play.roles for d in r.get_all_dependencies()}) # This is a list of all role names of all roles for this play play_role_names = [r.get_name() for r in play.roles] # ansible_role_names includes all role names, dependent or directly referenced by the play variables['ansible_role_names'] = list(set(dependency_role_names + play_role_names)) # ansible_play_role_names includes the names of all roles directly referenced by this play # roles that are implicitly referenced via dependencies are not listed. variables['ansible_play_role_names'] = play_role_names # ansible_dependent_role_names includes the names of all roles that are referenced via dependencies # dependencies that are also explicitly named as roles are included in this list variables['ansible_dependent_role_names'] = dependency_role_names # DEPRECATED: role_names should be deprecated in favor of ansible_role_names or ansible_play_role_names variables['role_names'] = variables['ansible_play_role_names'] variables['ansible_play_name'] = play.get_name() if task: if task._role: variables['role_name'] = task._role.get_name(include_role_fqcn=False) variables['role_path'] = task._role._role_path variables['role_uuid'] = text_type(task._role._uuid) variables['ansible_collection_name'] = task._role._role_collection variables['ansible_role_name'] = task._role.get_name() if self._inventory is not None: variables['groups'] = self._inventory.get_groups_dict() if play: templar = Templar(loader=self._loader) if not play.finalized and 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 if not _hosts_all: _hosts_all = [h.name for h in self._inventory.get_hosts(pattern=pattern, ignore_restrictions=True)] if not _hosts: _hosts = [h.name for h in self._inventory.get_hosts()] variables['ansible_play_hosts_all'] = _hosts_all[:] 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 for x in _hosts if x 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 allows params to be left out if the variable they are based on is undefined variables['omit'] = self._omit_token # Set options vars for option, option_value in self._options_vars.items(): variables[option] = option_value if self._hostvars is not None and include_hostvars: variables['hostvars'] = self._hostvars return variables def _get_delegated_vars(self, play, task, existing_variables): # This method has a lot of code copied from ``TaskExecutor._get_loop_items`` # if this is failing, and ``TaskExecutor._get_loop_items`` is not # then more will have to be copied here. # TODO: dedupe code here and with ``TaskExecutor._get_loop_items`` # this may be possible once we move pre-processing pre fork if not hasattr(task, 'loop'): # This "task" is not a Task, so we need to skip it return {}, None # 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() # get search path for this task to pass to lookup plugins vars_copy['ansible_search_path'] = task.get_search_path() # ensure basedir is always in (dwim already searches here but we need to display it) if self._loader.get_basedir() not in vars_copy['ansible_search_path']: vars_copy['ansible_search_path'].append(self._loader.get_basedir()) templar = Templar(loader=self._loader, variables=vars_copy) items = [] has_loop = True if task.loop_with is not None: if task.loop_with in lookup_loader: fail = True if task.loop_with == 'first_found': # first_found loops are special. If the item is undefined then we want to fall through to the next fail = False try: loop_terms = listify_lookup_plugin_terms(terms=task.loop, templar=templar, fail_on_undefined=fail, convert_bare=False) if not fail: loop_terms = [t for t in loop_terms if not templar.is_template(t)] mylookup = lookup_loader.get(task.loop_with, loader=self._loader, templar=templar) # give lookup task 'context' for subdir (mostly needed for first_found) for subdir in ['template', 'var', 'file']: # TODO: move this to constants? if subdir in task.action: break setattr(mylookup, '_subdir', subdir + 's') items = wrap_var(mylookup.run(terms=loop_terms, variables=vars_copy)) except AnsibleTemplateError: # 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("Failed to find the lookup named '%s' in the available lookup plugins" % task.loop_with) elif task.loop is not None: try: items = templar.template(task.loop) except AnsibleTemplateError: # 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: has_loop = False items = [None] # since host can change per loop, we keep dict per host name resolved delegated_host_vars = dict() item_var = getattr(task.loop_control, 'loop_var', 'item') cache_items = False 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_var] = item templar.available_variables = vars_copy delegated_host_name = templar.template(task.delegate_to, fail_on_undefined=False) if delegated_host_name != task.delegate_to: cache_items = True if delegated_host_name is None: raise AnsibleError(message="Undefined delegate_to host for task:", obj=task._ds) if not isinstance(delegated_host_name, string_types): raise AnsibleError(message="the field 'delegate_to' has an invalid type (%s), and could not be" " converted to a string type." % type(delegated_host_name), 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 # 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: 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) else: delegated_host = Host(name=delegated_host_name) # 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( play=play, host=delegated_host, task=task, include_delegate_to=False, include_hostvars=True, ) delegated_host_vars[delegated_host_name]['inventory_hostname'] = vars_copy.get('inventory_hostname') _ansible_loop_cache = None if has_loop and cache_items: # delegate_to templating produced a change, so we will cache the templated items # in a special private hostvar # this ensures that delegate_to+loop doesn't produce different results than TaskExecutor # which may reprocess the loop _ansible_loop_cache = items return delegated_host_vars, _ansible_loop_cache def clear_facts(self, hostname): ''' Clears the facts for a host ''' self._fact_cache.pop(hostname, None) def set_host_facts(self, host, facts): ''' Sets or updates the given facts for a host in the fact cache. ''' if not isinstance(facts, Mapping): raise AnsibleAssertionError("the type of 'facts' to set for host_facts should be a Mapping but is a %s" % type(facts)) try: host_cache = self._fact_cache[host] except KeyError: # We get to set this as new host_cache = facts else: if not isinstance(host_cache, MutableMapping): raise TypeError('The object retrieved for {0} must be a MutableMapping but was' ' a {1}'.format(host, type(host_cache))) # Update the existing facts host_cache |= facts # Save the facts back to the backing store self._fact_cache[host] = host_cache def set_nonpersistent_facts(self, host, facts): ''' Sets or updates the given facts for a host in the fact cache. ''' if not isinstance(facts, Mapping): raise AnsibleAssertionError("the type of 'facts' to set for nonpersistent_facts should be a Mapping but is a %s" % type(facts)) try: self._nonpersistent_fact_cache[host] |= facts except KeyError: self._nonpersistent_fact_cache[host] = facts def set_host_variable(self, host, varname, value): ''' Sets a value in the vars_cache for a host. ''' if host not in self._vars_cache: self._vars_cache[host] = dict() if varname in self._vars_cache[host] and isinstance(self._vars_cache[host][varname], MutableMapping) and isinstance(value, MutableMapping): self._vars_cache[host] = combine_vars(self._vars_cache[host], {varname: value}) else: self._vars_cache[host][varname] = value class VarsWithSources(MutableMapping): ''' Dict-like class for vars that also provides source information for each var This class can only store the source for top-level vars. It does no tracking on its own, just shows a debug message with the information that it is provided when a particular var is accessed. ''' def __init__(self, *args, **kwargs): ''' Dict-compatible constructor ''' self.data = dict(*args, **kwargs) self.sources = {} @classmethod def new_vars_with_sources(cls, data, sources): ''' Alternate constructor method to instantiate class with sources ''' v = cls(data) v.sources = sources return v def get_source(self, key): return self.sources.get(key, None) def __getitem__(self, key): val = self.data[key] # See notes in the VarsWithSources docstring for caveats and limitations of the source tracking display.debug("variable '%s' from source: %s" % (key, self.sources.get(key, "unknown"))) return val def __setitem__(self, key, value): self.data[key] = value def __delitem__(self, key): del self.data[key] def __iter__(self): return iter(self.data) def __len__(self): return len(self.data) # Prevent duplicate debug messages by defining our own __contains__ pointing at the underlying dict def __contains__(self, key): return self.data.__contains__(key) def copy(self): return VarsWithSources.new_vars_with_sources(self.data.copy(), self.sources.copy())