mirror of
https://github.com/ansible-collections/community.general.git
synced 2024-09-14 20:13:21 +02:00
a5765143f1
* dconf: Correctly handle setting a key that has no value in DB We need to check if the value in the database is None before we try to parse it, because the GVariant parser won't accept None as an input value. By definition if the value is None, i.e., there's no value in the database, than any value the user is trying to set is a change, so just indicate that it's a change without trying to compare the None to whatever the user specified as the value.x * dconf: Give a more useful error when writing a key fails if writing a key fails, then include in the error that is returned the exact key and value aguments that were given to the dconf command, to assist in diagnosing failures caused by providing the key or value in the wrong format.x * dconf: Convert boolean values into the format that dconf expects Even though we warn users to be careful to specify GVariant strings for values, a common error is to be trying to specify a boolean string which ends up getting converted into a boolean by the YAML parser or Ansible. Then it gets converted to "True" or "False", the string representations of Python booleans, which are not valid GVariants. Rather than just failing with an obscure error when this happens, let's be more user-friendly and detect when the user has specified a boolean and convert it into the correct GVariant forms, "true" or "false", so it just works. There's no good reason to be more pedantic than that.
461 lines
17 KiB
Python
461 lines
17 KiB
Python
#!/usr/bin/python
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# -*- coding: utf-8 -*-
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# Copyright (c) 2017, Branko Majic <branko@majic.rs>
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# GNU General Public License v3.0+ (see LICENSES/GPL-3.0-or-later.txt or https://www.gnu.org/licenses/gpl-3.0.txt)
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# SPDX-License-Identifier: GPL-3.0-or-later
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from __future__ import absolute_import, division, print_function
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__metaclass__ = type
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DOCUMENTATION = r'''
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module: dconf
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author:
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- "Branko Majic (@azaghal)"
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short_description: Modify and read dconf database
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description:
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- This module allows modifications and reading of C(dconf) database. The module
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is implemented as a wrapper around C(dconf) tool. Please see the dconf(1) man
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page for more details.
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- Since C(dconf) requires a running D-Bus session to change values, the module
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will try to detect an existing session and reuse it, or run the tool via
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C(dbus-run-session).
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requirements:
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- Optionally the C(gi.repository) Python library (usually included in the OS
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on hosts which have C(dconf)); this will become a non-optional requirement
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in a future major release of community.general.
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notes:
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- This module depends on C(psutil) Python library (version 4.0.0 and upwards),
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C(dconf), C(dbus-send), and C(dbus-run-session) binaries. Depending on
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distribution you are using, you may need to install additional packages to
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have these available.
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- This module uses the C(gi.repository) Python library when available for
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accurate comparison of values in C(dconf) to values specified in Ansible
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code. C(gi.repository) is likely to be present on most systems which have
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C(dconf) but may not be present everywhere. When it is missing, a simple
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string comparison between values is used, and there may be false positives,
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that is, Ansible may think that a value is being changed when it is not.
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This fallback will be removed in a future version of this module, at which
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point the module will stop working on hosts without C(gi.repository).
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- Detection of existing, running D-Bus session, required to change settings
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via C(dconf), is not 100% reliable due to implementation details of D-Bus
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daemon itself. This might lead to running applications not picking-up
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changes on the fly if options are changed via Ansible and
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C(dbus-run-session).
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- Keep in mind that the C(dconf) CLI tool, which this module wraps around,
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utilises an unusual syntax for the values (GVariant). For example, if you
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wanted to provide a string value, the correct syntax would be
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I(value="'myvalue'") - with single quotes as part of the Ansible parameter
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value.
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- When using loops in combination with a value like
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:code:`"[('xkb', 'us'), ('xkb', 'se')]"`, you need to be aware of possible
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type conversions. Applying a filter :code:`"{{ item.value | string }}"`
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to the parameter variable can avoid potential conversion problems.
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- The easiest way to figure out exact syntax/value you need to provide for a
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key is by making the configuration change in application affected by the
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key, and then having a look at value set via commands C(dconf dump
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/path/to/dir/) or C(dconf read /path/to/key).
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extends_documentation_fragment:
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- community.general.attributes
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attributes:
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check_mode:
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support: full
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diff_mode:
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support: none
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options:
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key:
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type: str
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required: true
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description:
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- A dconf key to modify or read from the dconf database.
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value:
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type: raw
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required: false
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description:
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- Value to set for the specified dconf key. Value should be specified in
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GVariant format. Due to complexity of this format, it is best to have a
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look at existing values in the dconf database.
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- Required for I(state=present).
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- Although the type is specified as "raw", it should typically be
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specified as a string. However, boolean values in particular are
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handled properly even when specified as booleans rather than strings
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(in fact, handling booleans properly is why the type of this parameter
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is "raw").
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state:
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type: str
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required: false
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default: present
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choices: [ 'read', 'present', 'absent' ]
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description:
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- The action to take upon the key/value.
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'''
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RETURN = r"""
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value:
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description: value associated with the requested key
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returned: success, state was "read"
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type: str
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sample: "'Default'"
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"""
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EXAMPLES = r"""
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- name: Configure available keyboard layouts in Gnome
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community.general.dconf:
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key: "/org/gnome/desktop/input-sources/sources"
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value: "[('xkb', 'us'), ('xkb', 'se')]"
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state: present
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- name: Read currently available keyboard layouts in Gnome
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community.general.dconf:
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key: "/org/gnome/desktop/input-sources/sources"
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state: read
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register: keyboard_layouts
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- name: Reset the available keyboard layouts in Gnome
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community.general.dconf:
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key: "/org/gnome/desktop/input-sources/sources"
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state: absent
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- name: Configure available keyboard layouts in Cinnamon
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community.general.dconf:
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key: "/org/gnome/libgnomekbd/keyboard/layouts"
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value: "['us', 'se']"
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state: present
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- name: Read currently available keyboard layouts in Cinnamon
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community.general.dconf:
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key: "/org/gnome/libgnomekbd/keyboard/layouts"
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state: read
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register: keyboard_layouts
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- name: Reset the available keyboard layouts in Cinnamon
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community.general.dconf:
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key: "/org/gnome/libgnomekbd/keyboard/layouts"
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state: absent
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- name: Disable desktop effects in Cinnamon
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community.general.dconf:
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key: "/org/cinnamon/desktop-effects"
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value: "false"
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state: present
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"""
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import os
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import traceback
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try:
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from gi.repository.GLib import Variant, GError
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except ImportError:
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Variant = None
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GError = AttributeError
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PSUTIL_IMP_ERR = None
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try:
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import psutil
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HAS_PSUTIL = True
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except ImportError:
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PSUTIL_IMP_ERR = traceback.format_exc()
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HAS_PSUTIL = False
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from ansible.module_utils.basic import AnsibleModule, missing_required_lib
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from ansible.module_utils.common.text.converters import to_native
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class DBusWrapper(object):
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"""
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Helper class that can be used for running a command with a working D-Bus
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session.
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If possible, command will be run against an existing D-Bus session,
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otherwise the session will be spawned via dbus-run-session.
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Example usage:
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dbus_wrapper = DBusWrapper(ansible_module)
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dbus_wrapper.run_command(["printenv", "DBUS_SESSION_BUS_ADDRESS"])
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"""
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def __init__(self, module):
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"""
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Initialises an instance of the class.
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:param module: Ansible module instance used to signal failures and run commands.
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:type module: AnsibleModule
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"""
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# Store passed-in arguments and set-up some defaults.
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self.module = module
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# Try to extract existing D-Bus session address.
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self.dbus_session_bus_address = self._get_existing_dbus_session()
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# If no existing D-Bus session was detected, check if dbus-run-session
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# is available.
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if self.dbus_session_bus_address is None:
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self.dbus_run_session_cmd = self.module.get_bin_path('dbus-run-session', required=True)
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def _get_existing_dbus_session(self):
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"""
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Detects and returns an existing D-Bus session bus address.
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:returns: string -- D-Bus session bus address. If a running D-Bus session was not detected, returns None.
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"""
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# We'll be checking the processes of current user only.
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uid = os.getuid()
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# Go through all the pids for this user, try to extract the D-Bus
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# session bus address from environment, and ensure it is possible to
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# connect to it.
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self.module.debug("Trying to detect existing D-Bus user session for user: %d" % uid)
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for pid in psutil.pids():
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try:
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process = psutil.Process(pid)
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process_real_uid, dummy, dummy = process.uids()
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if process_real_uid == uid and 'DBUS_SESSION_BUS_ADDRESS' in process.environ():
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dbus_session_bus_address_candidate = process.environ()['DBUS_SESSION_BUS_ADDRESS']
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self.module.debug("Found D-Bus user session candidate at address: %s" % dbus_session_bus_address_candidate)
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dbus_send_cmd = self.module.get_bin_path('dbus-send', required=True)
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command = [dbus_send_cmd, '--address=%s' % dbus_session_bus_address_candidate, '--type=signal', '/', 'com.example.test']
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rc, dummy, dummy = self.module.run_command(command)
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if rc == 0:
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self.module.debug("Verified D-Bus user session candidate as usable at address: %s" % dbus_session_bus_address_candidate)
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return dbus_session_bus_address_candidate
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# This can happen with things like SSH sessions etc.
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except psutil.AccessDenied:
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pass
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# Process has disappeared while inspecting it
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except psutil.NoSuchProcess:
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pass
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self.module.debug("Failed to find running D-Bus user session, will use dbus-run-session")
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return None
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def run_command(self, command):
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"""
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Runs the specified command within a functional D-Bus session. Command is
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effectively passed-on to AnsibleModule.run_command() method, with
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modification for using dbus-run-session if necessary.
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:param command: Command to run, including parameters. Each element of the list should be a string.
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:type module: list
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:returns: tuple(result_code, standard_output, standard_error) -- Result code, standard output, and standard error from running the command.
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"""
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if self.dbus_session_bus_address is None:
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self.module.debug("Using dbus-run-session wrapper for running commands.")
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command = [self.dbus_run_session_cmd] + command
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rc, out, err = self.module.run_command(command)
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if self.dbus_session_bus_address is None and rc == 127:
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self.module.fail_json(msg="Failed to run passed-in command, dbus-run-session faced an internal error: %s" % err)
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else:
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extra_environment = {'DBUS_SESSION_BUS_ADDRESS': self.dbus_session_bus_address}
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rc, out, err = self.module.run_command(command, environ_update=extra_environment)
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return rc, out, err
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class DconfPreference(object):
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def __init__(self, module, check_mode=False):
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"""
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Initialises instance of the class.
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:param module: Ansible module instance used to signal failures and run commands.
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:type module: AnsibleModule
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:param check_mode: Specify whether to only check if a change should be made or if to actually make a change.
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:type check_mode: bool
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"""
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self.module = module
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self.check_mode = check_mode
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# Check if dconf binary exists
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self.dconf_bin = self.module.get_bin_path('dconf', required=True)
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@staticmethod
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def variants_are_equal(canonical_value, user_value):
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"""Compare two string GVariant representations for equality.
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Assumes `canonical_value` is "canonical" in the sense that the type of
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the variant is specified explicitly if it cannot be inferred; this is
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true for textual representations of variants generated by the `dconf`
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command. The type of `canonical_value` is used to parse `user_value`,
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so the latter does not need to be explicitly typed.
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Returns True if the two values are equal.
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"""
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if canonical_value is None:
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# It's unset in dconf database, so anything the user is trying to
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# set is a change.
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return False
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try:
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variant1 = Variant.parse(None, canonical_value)
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variant2 = Variant.parse(variant1.get_type(), user_value)
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return variant1 == variant2
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except GError:
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return canonical_value == user_value
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def read(self, key):
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"""
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Retrieves current value associated with the dconf key.
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If an error occurs, a call will be made to AnsibleModule.fail_json.
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:returns: string -- Value assigned to the provided key. If the value is not set for specified key, returns None.
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"""
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command = [self.dconf_bin, "read", key]
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rc, out, err = self.module.run_command(command)
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if rc != 0:
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self.module.fail_json(msg='dconf failed while reading the value with error: %s' % err,
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out=out,
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err=err)
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if out == '':
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value = None
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else:
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value = out.rstrip('\n')
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return value
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def write(self, key, value):
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"""
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Writes the value for specified key.
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If an error occurs, a call will be made to AnsibleModule.fail_json.
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:param key: dconf key for which the value should be set. Should be a full path.
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:type key: str
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:param value: Value to set for the specified dconf key. Should be specified in GVariant format.
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:type value: str
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:returns: bool -- True if a change was made, False if no change was required.
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"""
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# If no change is needed (or won't be done due to check_mode), notify
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# caller straight away.
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if self.variants_are_equal(self.read(key), value):
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return False
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elif self.check_mode:
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return True
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# Set-up command to run. Since DBus is needed for write operation, wrap
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# dconf command dbus-launch.
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command = [self.dconf_bin, "write", key, value]
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# Run the command and fetch standard return code, stdout, and stderr.
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dbus_wrapper = DBusWrapper(self.module)
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rc, out, err = dbus_wrapper.run_command(command)
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if rc != 0:
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self.module.fail_json(msg='dconf failed while writing key %s, value %s with error: %s' % (key, value, err),
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out=out,
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err=err)
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# Value was changed.
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return True
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def reset(self, key):
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"""
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Returns value for the specified key (removes it from user configuration).
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If an error occurs, a call will be made to AnsibleModule.fail_json.
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:param key: dconf key to reset. Should be a full path.
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:type key: str
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:returns: bool -- True if a change was made, False if no change was required.
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"""
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# Read the current value first.
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current_value = self.read(key)
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# No change was needed, key is not set at all, or just notify user if we
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# are in check mode.
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if current_value is None:
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return False
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elif self.check_mode:
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return True
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# Set-up command to run. Since DBus is needed for reset operation, wrap
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# dconf command dbus-launch.
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command = [self.dconf_bin, "reset", key]
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# Run the command and fetch standard return code, stdout, and stderr.
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dbus_wrapper = DBusWrapper(self.module)
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rc, out, err = dbus_wrapper.run_command(command)
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if rc != 0:
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self.module.fail_json(msg='dconf failed while reseting the value with error: %s' % err,
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out=out,
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err=err)
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# Value was changed.
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return True
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def main():
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# Setup the Ansible module
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module = AnsibleModule(
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argument_spec=dict(
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state=dict(default='present', choices=['present', 'absent', 'read']),
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key=dict(required=True, type='str', no_log=False),
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# Converted to str below after special handling of bool.
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value=dict(required=False, default=None, type='raw'),
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),
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supports_check_mode=True
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)
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# Try to be forgiving about the user specifying a boolean as the value, or
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# more accurately about the fact that YAML and Ansible are quite insistent
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# about converting strings that look like booleans into booleans. Convert
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# the boolean into a string of the type dconf will understand. Any type for
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# the value other than boolean is just converted into a string directly.
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if module.params['value'] is not None:
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if isinstance(module.params['value'], bool):
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module.params['value'] = 'true' if module.params['value'] else 'false'
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else:
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module.params['value'] = to_native(
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module.params['value'], errors='surrogate_or_strict')
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if Variant is None:
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module.warn(
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'WARNING: The gi.repository Python library is not available; '
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'using string comparison to check value equality. This fallback '
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'will be deprecated in a future version of community.general.')
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if not HAS_PSUTIL:
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module.fail_json(msg=missing_required_lib("psutil"), exception=PSUTIL_IMP_ERR)
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# If present state was specified, value must be provided.
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if module.params['state'] == 'present' and module.params['value'] is None:
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module.fail_json(msg='State "present" requires "value" to be set.')
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# Create wrapper instance.
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dconf = DconfPreference(module, module.check_mode)
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# Process based on different states.
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if module.params['state'] == 'read':
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value = dconf.read(module.params['key'])
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module.exit_json(changed=False, value=value)
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elif module.params['state'] == 'present':
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changed = dconf.write(module.params['key'], module.params['value'])
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module.exit_json(changed=changed)
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elif module.params['state'] == 'absent':
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changed = dconf.reset(module.params['key'])
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module.exit_json(changed=changed)
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if __name__ == '__main__':
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main()
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