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community.general/plugins/module_utils/module_helper.py

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Adding module_utils/module_helper.py + big revamp in xfconf.py to use it (#1322) * Big revamp in xfconf.py - added plugin/module_utils/module_helper.py - scaffold class for writing modules, beyond standard AnsibleModule - automatic capture of exceptions - easier dependency testing - StateMixin to easily handle different behaviours for 'state' param - CmdMixin to easily run external commands - adapted test_xfconf.py - the args for run_command are now lists instead of a string - value and previous_value were not being tested before (because xfconf wasn't filling results - see below) - added more tests: setting value to previous_value, getting non-existent property - rewritten xfconf module, keeping the same results - original module posted results as ansible_facts, this version still does it for compatibility, but also adds to the module result * Added suggestions from the PR * Added russoz as maintainer for the module_utils/module_helper.py file * Formatting using printf-style requires special treatment Strings not containing substitution tokens must work as well. * Tidied up variables in module definition * Tests with ArgFormat and DependencyCtxMgr * pytest parameters must be in the same order, it seems * improved testing for the DependencyCtxMgr * fixed test for older pythons * Moved changed property to improve readability * Added testcase for state: absent and adjusted xfconf after it * Fixed param name environ_update in run_command() * added changelog fragment * fixed tests after run_command param change
2020-11-20 11:27:53 +01:00
# -*- coding: utf-8 -*-
# Copyright: (c) 2018, Ansible Project
# Simplified BSD License (see licenses/simplified_bsd.txt or https://opensource.org/licenses/BSD-2-Clause)
from __future__ import absolute_import, division, print_function
__metaclass__ = type
from functools import partial, wraps
import traceback
from ansible.module_utils.basic import AnsibleModule
class ArgFormat(object):
"""
Argument formatter
"""
BOOLEAN = 0
PRINTF = 1
FORMAT = 2
@staticmethod
def stars_deco(num):
if num == 1:
def deco(f):
return lambda v: f(*v)
return deco
elif num == 2:
def deco(f):
return lambda v: f(**v)
return deco
return lambda f: f
def __init__(self, name, fmt=None, style=FORMAT, stars=0):
"""
Creates a new formatter
:param name: Name of the argument to be formatted
:param fmt: Either a str to be formatted (using or not printf-style) or a callable that does that
:param style: Whether arg_format (as str) should use printf-style formatting.
Ignored if arg_format is None or not a str (should be callable).
:param stars: A int with 0, 1 or 2 value, indicating to formatting the value as: value, *value or **value
"""
def printf_fmt(_fmt, v):
try:
return [_fmt % v]
except TypeError as e:
if e.args[0] != 'not all arguments converted during string formatting':
raise
return [_fmt]
_fmts = {
ArgFormat.BOOLEAN: lambda _fmt, v: ([_fmt] if bool(v) else []),
ArgFormat.PRINTF: printf_fmt,
ArgFormat.FORMAT: lambda _fmt, v: [_fmt.format(v)],
}
self.name = name
self.stars = stars
if fmt is None:
fmt = "{0}"
style = ArgFormat.FORMAT
if isinstance(fmt, str):
func = _fmts[style]
self.arg_format = partial(func, fmt)
elif isinstance(fmt, list) or isinstance(fmt, tuple):
self.arg_format = lambda v: [_fmts[style](f, v)[0] for f in fmt]
elif hasattr(fmt, '__call__'):
self.arg_format = fmt
else:
raise TypeError('Parameter fmt must be either: a string, a list/tuple of '
'strings or a function: type={0}, value={1}'.format(type(fmt), fmt))
if stars:
self.arg_format = (self.stars_deco(stars))(self.arg_format)
def to_text(self, value):
func = self.arg_format
return [str(p) for p in func(value)]
def cause_changes(func, on_success=True, on_failure=False):
@wraps(func)
def wrapper(self, *args, **kwargs):
try:
func(*args, **kwargs)
if on_success:
self.changed = True
except Exception as e:
if on_failure:
self.changed = True
raise
return wrapper
def module_fails_on_exception(func):
@wraps(func)
def wrapper(self, *args, **kwargs):
try:
func(self, *args, **kwargs)
except SystemExit:
raise
except Exception as e:
self.vars.msg = "Module failed with exception: {0}".format(str(e).strip())
self.vars.exception = traceback.format_exc()
self.module.fail_json(changed=False, msg=self.vars.msg, exception=self.vars.exception, output=self.output, vars=self.vars)
return wrapper
class DependencyCtxMgr(object):
def __init__(self, name, msg=None):
self.name = name
self.msg = msg
self.has_it = False
self.exc_type = None
self.exc_val = None
self.exc_tb = None
def __enter__(self):
pass
def __exit__(self, exc_type, exc_val, exc_tb):
self.has_it = exc_type is None
self.exc_type = exc_type
self.exc_val = exc_val
self.exc_tb = exc_tb
return not self.has_it
@property
def text(self):
return self.msg or str(self.exc_val)
class ModuleHelper(object):
_dependencies = []
module = {}
facts_name = None
class AttrDict(dict):
def __getattr__(self, item):
return self[item]
def __init__(self, module=None):
self.vars = ModuleHelper.AttrDict()
self.output_dict = dict()
self.facts_dict = dict()
self._changed = False
if module:
self.module = module
if not isinstance(module, AnsibleModule):
self.module = AnsibleModule(**self.module)
def update_output(self, **kwargs):
if kwargs:
self.output_dict.update(kwargs)
def update_facts(self, **kwargs):
if kwargs:
self.facts_dict.update(kwargs)
def __init_module__(self):
pass
def __run__(self):
raise NotImplementedError()
@property
def changed(self):
return self._changed
@changed.setter
def changed(self, value):
self._changed = value
@property
def output(self):
result = dict(self.vars)
result.update(self.output_dict)
if self.facts_name:
result['ansible_facts'] = {self.facts_name: self.facts_dict}
return result
@module_fails_on_exception
def run(self):
self.fail_on_missing_deps()
self.__init_module__()
self.__run__()
self.module.exit_json(changed=self.changed, **self.output_dict)
@classmethod
def dependency(cls, name, msg):
cls._dependencies.append(DependencyCtxMgr(name, msg))
return cls._dependencies[-1]
def fail_on_missing_deps(self):
for d in self._dependencies:
if not d.has_it:
self.module.fail_json(changed=False,
exception=d.exc_val.__traceback__.format_exc(),
msg=d.text,
**self.output_dict)
class StateMixin(object):
state_param = 'state'
default_state = None
def _state(self):
state = self.module.params.get(self.state_param)
return self.default_state if state is None else state
def __run__(self):
state = self._state()
self.vars.state = state
# resolve aliases
if state not in self.module.params:
aliased = [name for name, param in self.module.argument_spec.items() if state in param.get('aliases', [])]
if aliased:
state = aliased[0]
self.vars.effective_state = state
method = "state_{0}".format(state)
if not hasattr(self, method):
return self.__state_fallback__()
func = getattr(self, method)
return func()
def __state_fallback__(self):
raise ValueError("Cannot find method for state: {0}".format(self._state()))
class CmdMixin(object):
"""
Mixin for mapping module options to running a CLI command with its arguments.
"""
command = None
command_args_formats = dict()
check_rc = False
force_lang = "C"
@property
def module_formats(self):
result = {}
for param in self.module.params.keys():
result[param] = ArgFormat(param)
return result
@property
def custom_formats(self):
result = {}
for param, fmt_spec in self.command_args_formats.items():
result[param] = ArgFormat(param, **fmt_spec)
return result
def _calculate_args(self, extra_params=None, params=None):
def add_arg_formatted_param(_cmd_args, arg_format, _value):
args = [x for x in arg_format.to_text(_value)]
return _cmd_args + args
def find_format(_param):
return self.custom_formats.get(_param, self.module_formats.get(_param))
extra_params = extra_params or dict()
cmd_args = [self.module.get_bin_path(self.command)]
param_list = params if params else self.module.params.keys()
for param in param_list:
if param in self.module.argument_spec:
if param not in self.module.params:
continue
fmt = find_format(param)
value = self.module.params[param]
else:
if param not in extra_params:
continue
fmt = find_format(param)
value = extra_params[param]
self.cmd_args = cmd_args
cmd_args = add_arg_formatted_param(cmd_args, fmt, value)
return cmd_args
def process_command_output(self, rc, out, err):
return rc, out, err
def run_command(self, extra_params=None, params=None, *args, **kwargs):
self.vars['cmd_args'] = self._calculate_args(extra_params, params)
env_update = kwargs.get('environ_update', {})
check_rc = kwargs.get('check_rc', self.check_rc)
if self.force_lang:
env_update.update({'LANGUAGE': self.force_lang})
self.update_output(force_lang=self.force_lang)
rc, out, err = self.module.run_command(self.vars['cmd_args'],
environ_update=env_update,
check_rc=check_rc, *args, **kwargs)
self.update_output(rc=rc, stdout=out, stderr=err)
return self.process_command_output(rc, out, err)