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/plugins/loader.py

@@ -18,13 +18,15 @@ from collections import defaultdict
 
 from ansible import constants as C
 from ansible.errors import AnsibleError
-from ansible.module_utils._text import to_bytes, to_native, to_text
+from ansible.module_utils._text import to_bytes, to_text, to_native
+from ansible.module_utils.six import string_types
 from ansible.parsing.utils.yaml import from_yaml
 from ansible.parsing.yaml.loader import AnsibleLoader
 from ansible.plugins import get_plugin_class, MODULE_CACHE, PATH_CACHE, PLUGIN_PATH_CACHE
 from ansible.utils.display import Display
 from ansible.utils.plugin_docs import add_fragments
 
+
 display = Display()
 
 
@@ -32,6 +34,52 @@ def get_all_plugin_loaders():
     return [(name, obj) for (name, obj) in globals().items() if isinstance(obj, PluginLoader)]
 
 
+def add_all_plugin_dirs(path):
+    ''' add any existing plugin dirs in the path provided '''
+    b_path = to_bytes(path, errors='surrogate_or_strict')
+    if os.path.isdir(b_path):
+        for name, obj in get_all_plugin_loaders():
+            if obj.subdir:
+                plugin_path = os.path.join(b_path, to_bytes(obj.subdir))
+                if os.path.isdir(plugin_path):
+                    obj.add_directory(to_text(plugin_path))
+    else:
+        display.warning("Ignoring invalid path provided to plugin path: %s is not a directory" % to_native(path))
+
+
+def get_shell_plugin(shell_type=None, executable=None):
+
+    if not shell_type:
+        # default to sh
+        shell_type = 'sh'
+
+        # mostly for backwards compat
+        if executable:
+            if isinstance(executable, string_types):
+                shell_filename = os.path.basename(executable)
+                try:
+                    shell = shell_loader.get(shell_filename)
+                except Exception:
+                    shell = None
+
+                if shell is None:
+                    for shell in shell_loader.all():
+                        if shell_filename in shell.COMPATIBLE_SHELLS:
+                            shell_type = shell.SHELL_FAMILY
+                            break
+        else:
+            raise AnsibleError("Either a shell type or a shell executable must be provided ")
+
+    shell = shell_loader.get(shell_type)
+    if not shell:
+        raise AnsibleError("Could not find the shell plugin required (%s)." % shell_type)
+
+    if executable:
+        setattr(shell, 'executable', executable)
+
+    return shell
+
+
 class PluginLoader:
     '''
     PluginLoader loads plugins from the configured plugin directories.
@@ -394,6 +442,7 @@ class PluginLoader:
                 return None
 
         self._display_plugin_load(self.class_name, name, self._searched_paths, path, found_in_cache=found_in_cache, class_only=class_only)
+
         if not class_only:
             try:
                 obj = obj(*args, **kwargs)
@@ -513,6 +562,7 @@ class PluginLoader:
                     continue
 
             self._display_plugin_load(self.class_name, basename, self._searched_paths, path, found_in_cache=found_in_cache, class_only=class_only)
+
             if not class_only:
                 try:
                     obj = obj(*args, **kwargs)
@@ -774,3 +824,10 @@ httpapi_loader = PluginLoader(
     'httpapi_plugins',
     required_base_class='HttpApiBase',
 )
+
+become_loader = PluginLoader(
+    'BecomeModule',
+    'ansible.plugins.become',
+    C.DEFAULT_BECOME_PLUGIN_PATH,
+    'become_plugins'
+)