Become plugins (#50991)

* [WIP] become plugins

Move from hardcoded method to plugins for ease of use, expansion and overrides
  - load into connection as it is going to be the main consumer
  - play_context will also use to keep backwards compat API
  - ensure shell is used to construct commands when needed
  - migrate settings remove from base config in favor of plugin specific configs
  - cleanup ansible-doc
  - add become plugin docs
  - remove deprecated sudo/su code and keywords
  - adjust become options for cli
  - set plugin options from context
  - ensure config defs are avaialbe before instance
  - refactored getting the shell plugin, fixed tests
     - changed into regex as they were string matching, which does not work with random string generation
     - explicitly set flags for play context tests
 - moved plugin loading up front
 - now loads for basedir also
 - allow pyc/o for non m modules
 - fixes to tests and some plugins
 - migrate to play objects fro play_context
 - simiplify gathering
 -  added utf8 headers
 - moved option setting
 - add fail msg to dzdo
 - use tuple for multiple options on fail/missing
 - fix relative plugin paths
 - shift from play context to play
 - all tasks already inherit this from play directly
 - remove obsolete 'set play'
 - correct environment handling
 - add wrap_exe option to pfexec
 - fix runas to noop
 - fixed setting play context
 - added password configs
 - removed required false
 - remove from doc building till they are ready

future development:
  - deal with 'enable' and 'runas' which are not 'command wrappers' but 'state flags' and currently hardcoded in diff subsystems

* cleanup

  remove callers to removed func
  removed --sudo cli doc refs
  remove runas become_exe
  ensure keyerorr on plugin
  also fix backwards compat, missing method is attributeerror, not ansible error
  get remote_user consistently
  ignore missing system_tmpdirs on plugin load
  correct config precedence
  add deprecation
  fix networking imports
  backwards compat for plugins using BECOME_METHODS

* Port become_plugins to context.CLIARGS

This is a work in progress:
* Stop passing options around everywhere as we can use context.CLIARGS
  instead

* Refactor make_become_commands as asked for by alikins

* Typo in comment fix

* Stop loading values from the cli in more than one place

Both play and play_context were saving default values from the cli
arguments directly.  This changes things so that the default values are
loaded into the play and then play_context takes them from there.

* Rename BECOME_PLUGIN_PATH to DEFAULT_BECOME_PLUGIN_PATH

As alikins said, all other plugin paths are named
DEFAULT_plugintype_PLUGIN_PATH.  If we're going to rename these, that
should be done all at one time rather than piecemeal.

* One to throw away

This is a set of hacks to get setting FieldAttribute defaults to command
line args to work.  It's not fully done yet.

After talking it over with sivel and jimi-c this should be done by
fixing FieldAttributeBase and _get_parent_attribute() calls to do the
right thing when there is a non-None default.

What we want to be able to do ideally is something like this:

class Base(FieldAttributeBase):
    _check_mode = FieldAttribute([..] default=lambda: context.CLIARGS['check'])

class Play(Base):
    # lambda so that we have a chance to parse the command line args
    # before we get here.  In the future we might be able to restructure
    # this so that the cli parsing code runs before these classes are
    # defined.

class Task(Base):
    pass

And still have a playbook like this function:

---
- hosts:
  tasks:
  - command: whoami
    check_mode: True

(The check_mode test that is added as a separate commit in this PR will
let you test variations on this case).

There's a few separate reasons that the code doesn't let us do this or
a non-ugly workaround for this as written right now.  The fix that
jimi-c, sivel, and I talked about may let us do this or it may still
require a workaround (but less ugly) (having one class that has the
FieldAttributes with default values and one class that inherits from
that but just overrides the FieldAttributes which now have defaults)

* Revert "One to throw away"

This reverts commit 23aa883cbed11429ef1be2a2d0ed18f83a3b8064.

* Set FieldAttr defaults directly from CLIARGS

* Remove dead code

* Move timeout directly to PlayContext, it's never needed on Play

* just for backwards compat, add a static version of BECOME_METHODS to constants

* Make the become attr on the connection public, since it's used outside of the connection

* Logic fix

* Nuke connection testing if it supports specific become methods

* Remove unused vars

* Address rebase issues

* Fix path encoding issue

* Remove unused import

* Various cleanups

* Restore network_cli check in _low_level_execute_command

* type improvements for cliargs_deferred_get and swap shallowcopy to default to False

* minor cleanups

* Allow the su plugin to work, since it doesn't define a prompt the same way

* Fix up ksu become plugin

* Only set prompt if build_become_command was called

* Add helper to assist connection plugins in knowing they need to wait for a prompt

* Fix tests and code expectations

* Doc updates

* Various additional minor cleanups

* Make doas functional

* Don't change connection signature, load become plugin from TaskExecutor

* Remove unused imports

* Add comment about setting the become plugin on the playcontext

* Fix up tests for recent changes

* Support 'Password:' natively for the doas plugin

* Make default prompts raw

* wording cleanups. ci_complete

* Remove unrelated changes

* Address spelling mistake

* Restore removed test, and udpate to use new functionality

* Add changelog fragment

* Don't hard fail in set_attributes_from_cli on missing CLI keys

* Remove unrelated change to loader

* Remove internal deprecated FieldAttributes now

* Emit deprecation warnings now

lib/ansible/constants.py

@@ -12,6 +12,7 @@ from jinja2 import Template
 from string import ascii_letters, digits
 
 from ansible.module_utils._text import to_text
+from ansible.module_utils.common.collections import Sequence
 from ansible.module_utils.parsing.convert_bool import boolean, BOOLEANS_TRUE
 from ansible.module_utils.six import string_types
 from ansible.config.manager import ConfigManager, ensure_type, get_ini_config_value
@@ -68,32 +69,31 @@ def set_constant(name, value, export=vars()):
     export[name] = value
 
 
+class _DeprecatedSequenceConstant(Sequence):
+    def __init__(self, value, msg, version):
+        self._value = value
+        self._msg = msg
+        self._version = version
+
+    def __len__(self):
+        _deprecated(self._msg, version=self._version)
+        return len(self._value)
+
+    def __getitem__(self, y):
+        _deprecated(self._msg, version=self._version)
+        return self._value[y]
+
+
+# Deprecated constants
+BECOME_METHODS = _DeprecatedSequenceConstant(
+    ['sudo', 'su', 'pbrun', 'pfexec', 'doas', 'dzdo', 'ksu', 'runas', 'pmrun', 'enable', 'machinectl'],
+    ('ansible.constants.BECOME_METHODS is deprecated, please use '
+     'ansible.plugins.loader.become_loader. This list is statically '
+     'defined and may not include all become methods'),
+    '2.10'
+)
+
 # CONSTANTS ### yes, actual ones
-BECOME_METHODS = ['sudo', 'su', 'pbrun', 'pfexec', 'doas', 'dzdo', 'ksu', 'runas', 'pmrun', 'enable', 'machinectl']
-BECOME_ERROR_STRINGS = {
-    'sudo': 'Sorry, try again.',
-    'su': 'Authentication failure',
-    'pbrun': '',
-    'pfexec': '',
-    'doas': 'Permission denied',
-    'dzdo': 'Sorry, try again.',
-    'ksu': 'Password incorrect',
-    'pmrun': 'You are not permitted to run this command',
-    'enable': '',
-    'machinectl': '',
-}  # FIXME: deal with i18n
-BECOME_MISSING_STRINGS = {
-    'sudo': 'sorry, a password is required to run sudo',
-    'su': '',
-    'pbrun': '',
-    'pfexec': '',
-    'doas': 'Authorization required',
-    'dzdo': '',
-    'ksu': 'No password given',
-    'pmrun': '',
-    'enable': '',
-    'machinectl': '',
-}  # FIXME: deal with i18n
 BLACKLIST_EXTS = ('.pyc', '.pyo', '.swp', '.bak', '~', '.rpm', '.md', '.txt', '.rst')
 BOOL_TRUE = BOOLEANS_TRUE
 CONTROLLER_LANG = os.getenv('LANG', 'en_US.UTF-8')
@@ -104,7 +104,7 @@ DEFAULT_REMOTE_PASS = None
 DEFAULT_SUBSET = None
 DEFAULT_SU_PASS = None
 # FIXME: expand to other plugins, but never doc fragments
-CONFIGURABLE_PLUGINS = ('cache', 'callback', 'connection', 'inventory', 'lookup', 'shell', 'cliconf', 'httpapi')
+CONFIGURABLE_PLUGINS = ('become', 'cache', 'callback', 'cliconf', 'connection', 'httpapi', 'inventory', 'lookup', 'shell')
 # NOTE: always update the docs/docsite/Makefile to match
 DOCUMENTABLE_PLUGINS = CONFIGURABLE_PLUGINS + ('module', 'strategy', 'vars')
 IGNORE_FILES = ("COPYING", "CONTRIBUTING", "LICENSE", "README", "VERSION", "GUIDELINES")  # ignore during module search