ansible/lib/ansible/playbook/task.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

from ansible import constants as C
from ansible.errors import AnsibleError, AnsibleParserError, AnsibleUndefinedVariable, AnsibleAssertionError
from ansible.module_utils.six import iteritems, string_types
from ansible.module_utils._text import to_native
from ansible.parsing.mod_args import ModuleArgsParser
from ansible.parsing.yaml.objects import AnsibleBaseYAMLObject, AnsibleMapping
from ansible.plugins.loader import lookup_loader
from ansible.playbook.attribute import FieldAttribute
from ansible.playbook.base import Base
from ansible.playbook.become import Become
from ansible.playbook.block import Block
from ansible.playbook.conditional import Conditional
from ansible.playbook.loop_control import LoopControl
from ansible.playbook.role import Role
from ansible.playbook.taggable import Taggable
from ansible.utils.display import Display
from ansible.utils.sentinel import Sentinel

__all__ = ['Task']

display = Display()


class Task(Base, Conditional, Taggable, Become):

    """
    A task is a language feature that represents a call to a module, with given arguments and other parameters.
    A handler is a subclass of a task.

    Usage:

       Task.load(datastructure) -> Task
       Task.something(...)
    """

    # =================================================================================
    # ATTRIBUTES
    # load_<attribute_name> and
    # validate_<attribute_name>
    # will be used if defined
    # might be possible to define others

    # NOTE: ONLY set defaults on task attributes that are not inheritable,
    # inheritance is only triggered if the 'current value' is None,
    # default can be set at play/top level object and inheritance will take it's course.

    _args = FieldAttribute(isa='dict', default=dict)
    _action = FieldAttribute(isa='string')

    _async_val = FieldAttribute(isa='int', default=0, alias='async')
    _changed_when = FieldAttribute(isa='list', default=list)
    _delay = FieldAttribute(isa='int', default=5)
    _delegate_to = FieldAttribute(isa='string')
    _delegate_facts = FieldAttribute(isa='bool')
    _failed_when = FieldAttribute(isa='list', default=list)
    _loop = FieldAttribute()
    _loop_control = FieldAttribute(isa='class', class_type=LoopControl, inherit=False)
    _notify = FieldAttribute(isa='list')
    _poll = FieldAttribute(isa='int', default=10)
    _register = FieldAttribute(isa='string')
    _retries = FieldAttribute(isa='int', default=3)
    _until = FieldAttribute(isa='list', default=list)

    # deprecated, used to be loop and loop_args but loop has been repurposed
    _loop_with = FieldAttribute(isa='string', private=True, inherit=False)

    def __init__(self, block=None, role=None, task_include=None):
        ''' constructors a task, without the Task.load classmethod, it will be pretty blank '''

        self._role = role
        self._parent = None

        if task_include:
            self._parent = task_include
        else:
            self._parent = block

        super(Task, self).__init__()

    def get_path(self):
        ''' return the absolute path of the task with its line number '''

        path = ""
        if hasattr(self, '_ds') and hasattr(self._ds, '_data_source') and hasattr(self._ds, '_line_number'):
            path = "%s:%s" % (self._ds._data_source, self._ds._line_number)
        elif hasattr(self._parent._play, '_ds') and hasattr(self._parent._play._ds, '_data_source') and hasattr(self._parent._play._ds, '_line_number'):
            path = "%s:%s" % (self._parent._play._ds._data_source, self._parent._play._ds._line_number)
        return path

    def get_name(self):
        ''' return the name of the task '''

        if self._role and self.name and ("%s : " % self._role._role_name) not in self.name:
            return "%s : %s" % (self._role.get_name(), self.name)
        elif self.name:
            return self.name
        else:
            if self._role:
                return "%s : %s" % (self._role.get_name(), self.action)
            else:
                return "%s" % (self.action,)

    def _merge_kv(self, ds):
        if ds is None:
            return ""
        elif isinstance(ds, string_types):
            return ds
        elif isinstance(ds, dict):
            buf = ""
            for (k, v) in iteritems(ds):
                if k.startswith('_'):
                    continue
                buf = buf + "%s=%s " % (k, v)
            buf = buf.strip()
            return buf

    @staticmethod
    def load(data, block=None, role=None, task_include=None, variable_manager=None, loader=None):
        t = Task(block=block, role=role, task_include=task_include)
        return t.load_data(data, variable_manager=variable_manager, loader=loader)

    def __repr__(self):
        ''' returns a human readable representation of the task '''
        if self.get_name() == 'meta':
            return "TASK: meta (%s)" % self.args['_raw_params']
        else:
            return "TASK: %s" % self.get_name()

    def _preprocess_with_loop(self, ds, new_ds, k, v):
        ''' take a lookup plugin name and store it correctly '''

        loop_name = k.replace("with_", "")
        if new_ds.get('loop') is not None or new_ds.get('loop_with') is not None:
            raise AnsibleError("duplicate loop in task: %s" % loop_name, obj=ds)
        if v is None:
            raise AnsibleError("you must specify a value when using %s" % k, obj=ds)
        new_ds['loop_with'] = loop_name
        new_ds['loop'] = v
        # display.deprecated("with_ type loops are being phased out, use the 'loop' keyword instead", version="2.10")

    def preprocess_data(self, ds):
        '''
        tasks are especially complex arguments so need pre-processing.
        keep it short.
        '''

        if not isinstance(ds, dict):
            raise AnsibleAssertionError('ds (%s) should be a dict but was a %s' % (ds, type(ds)))

        # the new, cleaned datastructure, which will have legacy
        # items reduced to a standard structure suitable for the
        # attributes of the task class
        new_ds = AnsibleMapping()
        if isinstance(ds, AnsibleBaseYAMLObject):
            new_ds.ansible_pos = ds.ansible_pos

        # use the args parsing class to determine the action, args,
        # and the delegate_to value from the various possible forms
        # supported as legacy
        args_parser = ModuleArgsParser(task_ds=ds)
        try:
            (action, args, delegate_to) = args_parser.parse()
        except AnsibleParserError as e:
            # if the raises exception was created with obj=ds args, then it includes the detail
            # so we dont need to add it so we can just re raise.
            if e._obj:
                raise
            # But if it wasn't, we can add the yaml object now to get more detail
            raise AnsibleParserError(to_native(e), obj=ds, orig_exc=e)

        # the command/shell/script modules used to support the `cmd` arg,
        # which corresponds to what we now call _raw_params, so move that
        # value over to _raw_params (assuming it is empty)
        if action in ('command', 'shell', 'script'):
            if 'cmd' in args:
                if args.get('_raw_params', '') != '':
                    raise AnsibleError("The 'cmd' argument cannot be used when other raw parameters are specified."
                                       " Please put everything in one or the other place.", obj=ds)
                args['_raw_params'] = args.pop('cmd')

        new_ds['action'] = action
        new_ds['args'] = args
        new_ds['delegate_to'] = delegate_to

        # we handle any 'vars' specified in the ds here, as we may
        # be adding things to them below (special handling for includes).
        # When that deprecated feature is removed, this can be too.
        if 'vars' in ds:
            # _load_vars is defined in Base, and is used to load a dictionary
            # or list of dictionaries in a standard way
            new_ds['vars'] = self._load_vars(None, ds.get('vars'))
        else:
            new_ds['vars'] = dict()

        for (k, v) in iteritems(ds):
            if k in ('action', 'local_action', 'args', 'delegate_to') or k == action or k == 'shell':
                # we don't want to re-assign these values, which were determined by the ModuleArgsParser() above
                continue
            elif k.startswith('with_') and k.replace("with_", "") in lookup_loader:
                # transform into loop property
                self._preprocess_with_loop(ds, new_ds, k, v)
            else:
                # pre-2.0 syntax allowed variables for include statements at the top level of the task,
                # so we move those into the 'vars' dictionary here, and show a deprecation message
                # as we will remove this at some point in the future.
                if action in ('include',) and k not in self._valid_attrs and k not in self.DEPRECATED_ATTRIBUTES:
                    display.deprecated("Specifying include variables at the top-level of the task is deprecated."
                                       " Please see:\nhttps://docs.ansible.com/ansible/playbooks_roles.html#task-include-files-and-encouraging-reuse\n\n"
                                       " for currently supported syntax regarding included files and variables", version="2.12")
                    new_ds['vars'][k] = v
                elif C.INVALID_TASK_ATTRIBUTE_FAILED or k in self._valid_attrs:
                    new_ds[k] = v
                else:
                    display.warning("Ignoring invalid attribute: %s" % k)

        return super(Task, self).preprocess_data(new_ds)

    def _load_loop_control(self, attr, ds):
        if not isinstance(ds, dict):
            raise AnsibleParserError(
                "the `loop_control` value must be specified as a dictionary and cannot "
                "be a variable itself (though it can contain variables)",
                obj=ds,
            )

        return LoopControl.load(data=ds, variable_manager=self._variable_manager, loader=self._loader)

    def _validate_attributes(self, ds):
        try:
            super(Task, self)._validate_attributes(ds)
        except AnsibleParserError as e:
            e.message += '\nThis error can be suppressed as a warning using the "invalid_task_attribute_failed" configuration'
            raise e

    def post_validate(self, templar):
        '''
        Override of base class post_validate, to also do final validation on
        the block and task include (if any) to which this task belongs.
        '''

        if self._parent:
            self._parent.post_validate(templar)

        super(Task, self).post_validate(templar)

    def _post_validate_loop(self, attr, value, templar):
        '''
        Override post validation for the loop field, which is templated
        specially in the TaskExecutor class when evaluating loops.
        '''
        return value

    def _post_validate_environment(self, attr, value, templar):
        '''
        Override post validation of vars on the play, as we don't want to
        template these too early.
        '''
        env = {}
        if value is not None:

            def _parse_env_kv(k, v):
                try:
                    env[k] = templar.template(v, convert_bare=False)
                except AnsibleUndefinedVariable as e:
                    error = to_native(e)
                    if self.action in ('setup', 'gather_facts') and 'ansible_facts.env' in error or 'ansible_env' in error:
                        # ignore as fact gathering is required for 'env' facts
                        return
                    raise

            if isinstance(value, list):
                for env_item in value:
                    if isinstance(env_item, dict):
                        for k in env_item:
                            _parse_env_kv(k, env_item[k])
                    else:
                        isdict = templar.template(env_item, convert_bare=False)
                        if isinstance(isdict, dict):
                            env.update(isdict)
                        else:
                            display.warning("could not parse environment value, skipping: %s" % value)

            elif isinstance(value, dict):
                # should not really happen
                env = dict()
                for env_item in value:
                    _parse_env_kv(env_item, value[env_item])
            else:
                # at this point it should be a simple string, also should not happen
                env = templar.template(value, convert_bare=False)

        return env

    def _post_validate_changed_when(self, attr, value, templar):
        '''
        changed_when is evaluated after the execution of the task is complete,
        and should not be templated during the regular post_validate step.
        '''
        return value

    def _post_validate_failed_when(self, attr, value, templar):
        '''
        failed_when is evaluated after the execution of the task is complete,
        and should not be templated during the regular post_validate step.
        '''
        return value

    def _post_validate_until(self, attr, value, templar):
        '''
        until is evaluated after the execution of the task is complete,
        and should not be templated during the regular post_validate step.
        '''
        return value

    def get_vars(self):
        all_vars = dict()
        if self._parent:
            all_vars.update(self._parent.get_vars())

        all_vars.update(self.vars)

        if 'tags' in all_vars:
            del all_vars['tags']
        if 'when' in all_vars:
            del all_vars['when']

        return all_vars

    def get_include_params(self):
        all_vars = dict()
        if self._parent:
            all_vars.update(self._parent.get_include_params())
        if self.action in ('include', 'include_tasks', 'include_role'):
            all_vars.update(self.vars)
        return all_vars

    def copy(self, exclude_parent=False, exclude_tasks=False):
        new_me = super(Task, self).copy()

        new_me._parent = None
        if self._parent and not exclude_parent:
            new_me._parent = self._parent.copy(exclude_tasks=exclude_tasks)

        new_me._role = None
        if self._role:
            new_me._role = self._role

        return new_me

    def serialize(self):
        data = super(Task, self).serialize()

        if not self._squashed and not self._finalized:
            if self._parent:
                data['parent'] = self._parent.serialize()
                data['parent_type'] = self._parent.__class__.__name__

            if self._role:
                data['role'] = self._role.serialize()

        return data

    def deserialize(self, data):

        # import is here to avoid import loops
        from ansible.playbook.task_include import TaskInclude
        from ansible.playbook.handler_task_include import HandlerTaskInclude

        parent_data = data.get('parent', None)
        if parent_data:
            parent_type = data.get('parent_type')
            if parent_type == 'Block':
                p = Block()
            elif parent_type == 'TaskInclude':
                p = TaskInclude()
            elif parent_type == 'HandlerTaskInclude':
                p = HandlerTaskInclude()
            p.deserialize(parent_data)
            self._parent = p
            del data['parent']

        role_data = data.get('role')
        if role_data:
            r = Role()
            r.deserialize(role_data)
            self._role = r
            del data['role']

        super(Task, self).deserialize(data)

    def set_loader(self, loader):
        '''
        Sets the loader on this object and recursively on parent, child objects.
        This is used primarily after the Task has been serialized/deserialized, which
        does not preserve the loader.
        '''

        self._loader = loader

        if self._parent:
            self._parent.set_loader(loader)

    def _get_parent_attribute(self, attr, extend=False, prepend=False):
        '''
        Generic logic to get the attribute or parent attribute for a task value.
        '''

        extend = self._valid_attrs[attr].extend
        prepend = self._valid_attrs[attr].prepend
        try:
            value = self._attributes[attr]
            # If parent is static, we can grab attrs from the parent
            # otherwise, defer to the grandparent
            if getattr(self._parent, 'statically_loaded', True):
                _parent = self._parent
            else:
                _parent = self._parent._parent

            if _parent and (value is Sentinel or extend):
                if getattr(_parent, 'statically_loaded', True):
                    # vars are always inheritable, other attributes might not be for the parent but still should be for other ancestors
                    if attr != 'vars' and hasattr(_parent, '_get_parent_attribute'):
                        parent_value = _parent._get_parent_attribute(attr)
                    else:
                        parent_value = _parent._attributes.get(attr, Sentinel)

                    if extend:
                        value = self._extend_value(value, parent_value, prepend)
                    else:
                        value = parent_value
        except KeyError:
            pass

        return value

    def get_dep_chain(self):
        if self._parent:
            return self._parent.get_dep_chain()
        else:
            return None

    def get_search_path(self):
        '''
        Return the list of paths you should search for files, in order.
        This follows role/playbook dependency chain.
        '''
        path_stack = []

        dep_chain = self.get_dep_chain()
        # inside role: add the dependency chain from current to dependent
        if dep_chain:
            path_stack.extend(reversed([x._role_path for x in dep_chain]))

        # add path of task itself, unless it is already in the list
        task_dir = os.path.dirname(self.get_path())
        if task_dir not in path_stack:
            path_stack.append(task_dir)

        return path_stack

    def all_parents_static(self):
        if self._parent:
            return self._parent.all_parents_static()
        return True

    def get_first_parent_include(self):
        from ansible.playbook.task_include import TaskInclude
        if self._parent:
            if isinstance(self._parent, TaskInclude):
                return self._parent
            return self._parent.get_first_parent_include()
        return None