# (c) 2014 Michael DeHaan, <michael@ansible.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
from ansible.compat.six import iteritems, string_types
from ansible.errors import AnsibleParserError,AnsibleError
from ansible.plugins import module_loader
from ansible.parsing.splitter import parse_kv, split_args
from ansible.template import Templar
# For filtering out modules correctly below
RAW_PARAM_MODULES = ([
'command',
'shell',
'script',
'include',
'include_vars',
'add_host',
'group_by',
'set_fact',
'raw',
'meta',
])
class ModuleArgsParser:
"""
There are several ways a module and argument set can be expressed:
# legacy form (for a shell command)
- action: shell echo hi
# common shorthand for local actions vs delegate_to
- local_action: shell echo hi
# most commonly:
- copy: src=a dest=b
# legacy form
- action: copy src=a dest=b
# complex args form, for passing structured data
- copy:
src: a
dest: b
# gross, but technically legal
- action:
module: copy
args:
src: a
dest: b
# extra gross, but also legal. in this case, the args specified
# will act as 'defaults' and will be overridden by any args specified
# in one of the other formats (complex args under the action, or
# parsed from the k=v string
- command: 'pwd'
args:
chdir: '/tmp'
This class has some of the logic to canonicalize these into the form
- module: <module_name>
delegate_to: <optional>
args: <args>
Args may also be munged for certain shell command parameters.
"""
def __init__(self, task_ds=dict()):
assert isinstance(task_ds, dict)
self._task_ds = task_ds
def _split_module_string(self, module_string):
'''
when module names are expressed like:
action: copy src=a dest=b
the first part of the string is the name of the module
and the rest are strings pertaining to the arguments.
'''
tokens = split_args(module_string)
if len(tokens) > 1:
return (tokens[0], " ".join(tokens[1:]))
else:
return (tokens[0], "")
def _handle_shell_weirdness(self, action, args):
'''
given an action name and an args dictionary, return the
proper action name and args dictionary. This mostly is due
to shell/command being treated special and nothing else
'''
# the shell module really is the command module with an additional
# parameter
if action == 'shell':
action = 'command'
args['_uses_shell'] = True
return (action, args)
def _normalize_parameters(self, thing, action=None, additional_args=dict()):
'''
arguments can be fuzzy. Deal with all the forms.
'''
# final args are the ones we'll eventually return, so first update
# them with any additional args specified, which have lower priority
# than those which may be parsed/normalized next
final_args = dict()
if additional_args:
if isinstance(additional_args, string_types):
templar = Templar(loader=None)
if templar._contains_vars(additional_args):
final_args['_variable_params'] = additional_args
else:
raise AnsibleParserError("Complex args containing variables cannot use bare variables, and must use the full variable style ('{{var_name}}')")
elif isinstance(additional_args, dict):
final_args.update(additional_args)
else:
raise AnsibleParserError('Complex args must be a dictionary or variable string ("{{var}}").')
# how we normalize depends if we figured out what the module name is
# yet. If we have already figured it out, it's an 'old style' invocation.
# otherwise, it's not
if action is not None:
args = self._normalize_old_style_args(thing, action)
else:
(action, args) = self._normalize_new_style_args(thing)
# this can occasionally happen, simplify
if args and 'args' in args:
tmp_args = args.pop('args')
if isinstance(tmp_args, string_types):
tmp_args = parse_kv(tmp_args)
args.update(tmp_args)
# only internal variables can start with an underscore, so
# we don't allow users to set them directy in arguments
if args and action not in ('command', 'shell', 'script', 'raw'):
for arg in args:
if arg.startswith('_ansible_'):
raise AnsibleError("invalid parameter specified for action '%s': '%s'" % (action, arg))
# finally, update the args we're going to return with the ones
# which were normalized above
if args:
final_args.update(args)
return (action, final_args)
def _normalize_old_style_args(self, thing, action):
'''
deals with fuzziness in old-style (action/local_action) module invocations
returns tuple of (module_name, dictionary_args)
possible example inputs:
{ 'local_action' : 'shell echo hi' }
{ 'action' : 'shell echo hi' }
{ 'local_action' : { 'module' : 'ec2', 'x' : 1, 'y': 2 }}
standardized outputs like:
( 'command', { _raw_params: 'echo hi', _uses_shell: True }
'''
if isinstance(thing, dict):
# form is like: local_action: { module: 'xyz', x: 2, y: 3 } ... uncommon!
args = thing
elif isinstance(thing, string_types):
# form is like: local_action: copy src=a dest=b ... pretty common
check_raw = action in ('command', 'shell', 'script', 'raw')
args = parse_kv(thing, check_raw=check_raw)
elif thing is None:
# this can happen with modules which take no params, like ping:
args = None
else:
raise AnsibleParserError("unexpected parameter type in action: %s" % type(thing), obj=self._task_ds)
return args
def _normalize_new_style_args(self, thing):
'''
deals with fuzziness in new style module invocations
accepting key=value pairs and dictionaries, and always returning dictionaries
returns tuple of (module_name, dictionary_args)
possible example inputs:
{ 'shell' : 'echo hi' }
{ 'ec2' : { 'region' : 'xyz' }
{ 'ec2' : 'region=xyz' }
standardized outputs like:
('ec2', { region: 'xyz'} )
'''
action = None
args = None
actions_allowing_raw = ('command', 'shell', 'script', 'raw')
if isinstance(thing, dict):
# form is like: copy: { src: 'a', dest: 'b' } ... common for structured (aka "complex") args
thing = thing.copy()
if 'module' in thing:
action, module_args = self._split_module_string(thing['module'])
args = thing.copy()
check_raw = action in actions_allowing_raw
args.update(parse_kv(module_args, check_raw=check_raw))
del args['module']
elif isinstance(thing, string_types):
# form is like: copy: src=a dest=b ... common shorthand throughout ansible
(action, args) = self._split_module_string(thing)
check_raw = action in actions_allowing_raw
args = parse_kv(args, check_raw=check_raw)
else:
# need a dict or a string, so giving up
raise AnsibleParserError("unexpected parameter type in action: %s" % type(thing), obj=self._task_ds)
return (action, args)
def parse(self):
'''
Given a task in one of the supported forms, parses and returns
returns the action, arguments, and delegate_to values for the
task, dealing with all sorts of levels of fuzziness.
'''
thing = None
action = None
delegate_to = self._task_ds.get('delegate_to', None)
args = dict()
# this is the 'extra gross' scenario detailed above, so we grab
# the args and pass them in as additional arguments, which can/will
# be overwritten via dict updates from the other arg sources below
additional_args = self._task_ds.get('args', dict())
# We can have one of action, local_action, or module specified
# action
if 'action' in self._task_ds:
# an old school 'action' statement
thing = self._task_ds['action']
# local_action
if 'local_action' in self._task_ds:
# local_action is similar but also implies a delegate_to
if action is not None:
raise AnsibleParserError("action and local_action are mutually exclusive", obj=self._task_ds)
thing = self._task_ds.get('local_action', '')
delegate_to = 'localhost'
# module: <stuff> is the more new-style invocation
# walk the input dictionary to see we recognize a module name
for (item, value) in iteritems(self._task_ds):
if item in module_loader or item in ['meta', 'include', 'include_role']:
# finding more than one module name is a problem
if action is not None:
raise AnsibleParserError("conflicting action statements", obj=self._task_ds)
action = item
thing = value
#TODO: find out if we should break here? Currently last matching action, break would make it first one
action, args = self._normalize_parameters(thing, action=action, additional_args=additional_args)
# if we didn't see any module in the task at all, it's not a task really
if action is None:
if 'ping' not in module_loader:
raise AnsibleParserError("The requested action was not found in configured module paths. "
"Additionally, core modules are missing. If this is a checkout, "
"run 'git submodule update --init --recursive' to correct this problem.",
obj=self._task_ds)
else:
raise AnsibleParserError("no action detected in task. This often indicates a misspelled module name, or incorrect module path.", obj=self._task_ds)
elif args.get('_raw_params', '') != '' and action not in RAW_PARAM_MODULES:
templar = Templar(loader=None)
raw_params = args.pop('_raw_params')
if templar._contains_vars(raw_params):
args['_variable_params'] = raw_params
else:
raise AnsibleParserError("this task '%s' has extra params, which is only allowed in the following modules: %s" % (action, ", ".join(RAW_PARAM_MODULES)), obj=self._task_ds)
# shell modules require special handling
(action, args) = self._handle_shell_weirdness(action, args)
return (action, args, delegate_to)