searxng/searx/settings_loader.py
Markus Heiser 2039060b64 [mod] revision of the settings_loader
The intention of this PR is to modernize the settings_loader implementations.
The concept is old (remember, this is partly from 2014), back then we only had
one config file, meanwhile we have had a folder with config files for a very
long time.  Callers can now load a YAML configuration from this folder as
follows ::

    settings_loader.get_yaml_cfg('my-config.yml')

- BTW this is a fix of #3557.

- Further the `existing_filename_or_none` construct dates back to times when
  there was not yet a `pathlib.Path` in all Python versions we supported in the
  past.

- Typehints have been added wherever appropriate

At the same time, this patch should also be downward compatible and not
introduce a new environment variable. The localization of the folder with the
configurations is further based on:

    SEARXNG_SETTINGS_PATH (wich defaults to /etc/searxng/settings.yml)

Which means, the default config folder is `/etc/searxng/`.

ATTENTION: intended functional changes!

 If SEARXNG_SETTINGS_PATH was set and pointed to a not existing file, the
 previous implementation silently loaded the default configuration.  This
 behavior has been changed: if the file or folder does not exist, an
 EnvironmentError exception will be thrown in future.

Closes: https://github.com/searxng/searxng/issues/3557
Signed-off-by: Markus Heiser <markus.heiser@darmarit.de>
2024-07-14 18:10:06 +02:00

221 lines
8.1 KiB
Python

# SPDX-License-Identifier: AGPL-3.0-or-later
"""Implementations for loading configurations from YAML files. This essentially
includes the configuration of the (:ref:`SearXNG appl <searxng settings.yml>`)
server. The default configuration for the application server is loaded from the
:origin:`DEFAULT_SETTINGS_FILE <searx/settings.yml>`. This default
configuration can be completely replaced or :ref:`customized individually
<use_default_settings.yml>` and the ``SEARXNG_SETTINGS_PATH`` environment
variable can be used to set the location from which the local customizations are
to be loaded. The rules used for this can be found in the
:py:obj:`get_user_cfg_folder` function.
- By default, local configurations are expected in folder ``/etc/searxng`` from
where applications can load them with the :py:obj:`get_yaml_cfg` function.
- By default, customized :ref:`SearXNG appl <searxng settings.yml>` settings are
expected in a file named ``settings.yml``.
"""
from __future__ import annotations
import os.path
from collections.abc import Mapping
from itertools import filterfalse
from pathlib import Path
import yaml
from searx.exceptions import SearxSettingsException
searx_dir = os.path.abspath(os.path.dirname(__file__))
SETTINGS_YAML = Path("settings.yml")
DEFAULT_SETTINGS_FILE = Path(searx_dir) / SETTINGS_YAML
"""The :origin:`searx/settings.yml` file with all the default settings."""
def load_yaml(file_name: str | Path):
"""Load YAML config from a file."""
try:
with open(file_name, 'r', encoding='utf-8') as settings_yaml:
return yaml.safe_load(settings_yaml) or {}
except IOError as e:
raise SearxSettingsException(e, str(file_name)) from e
except yaml.YAMLError as e:
raise SearxSettingsException(e, str(file_name)) from e
def get_yaml_cfg(file_name: str | Path) -> dict:
"""Shortcut to load a YAML config from a file, located in the
- :py:obj:`get_user_cfg_folder` or
- in the ``searx`` folder of the SearXNG installation
"""
folder = get_user_cfg_folder() or Path(searx_dir)
fname = folder / file_name
if not fname.is_file():
raise FileNotFoundError(f"File {fname} does not exist!")
return load_yaml(fname)
def get_user_cfg_folder() -> Path | None:
"""Returns folder where the local configurations are located.
1. If the ``SEARXNG_SETTINGS_PATH`` environment is set and points to a
folder (e.g. ``/etc/mysxng/``), all local configurations are expected in
this folder. The settings of the :ref:`SearXNG appl <searxng
settings.yml>` then expected in ``settings.yml``
(e.g. ``/etc/mysxng/settings.yml``).
2. If the ``SEARXNG_SETTINGS_PATH`` environment is set and points to a file
(e.g. ``/etc/mysxng/myinstance.yml``), this file contains the settings of
the :ref:`SearXNG appl <searxng settings.yml>` and the folder
(e.g. ``/etc/mysxng/``) is used for all other configurations.
This type (``SEARXNG_SETTINGS_PATH`` points to a file) is suitable for
use cases in which different profiles of the :ref:`SearXNG appl <searxng
settings.yml>` are to be managed, such as in test scenarios.
3. If folder ``/etc/searxng`` exists, it is used.
In case none of the above path exists, ``None`` is returned. In case of
environment ``SEARXNG_SETTINGS_PATH`` is set, but the (folder or file) does
not exists, a :py:obj:`EnvironmentError` is raised.
"""
folder = None
settings_path = os.environ.get("SEARXNG_SETTINGS_PATH")
# Disable default /etc/searxng is intended exclusively for internal testing purposes
# and is therefore not documented!
disable_etc = os.environ.get('SEARXNG_DISABLE_ETC_SETTINGS', '').lower() in ('1', 'true')
if settings_path:
# rule 1. and 2.
settings_path = Path(settings_path)
if settings_path.is_dir():
folder = settings_path
elif settings_path.is_file():
folder = settings_path.parent
else:
raise EnvironmentError(1, f"{settings_path} not exists!", settings_path)
if not folder and not disable_etc:
# default: rule 3.
folder = Path("/etc/searxng")
if not folder.is_dir():
folder = None
return folder
def update_dict(default_dict, user_dict):
for k, v in user_dict.items():
if isinstance(v, Mapping):
default_dict[k] = update_dict(default_dict.get(k, {}), v)
else:
default_dict[k] = v
return default_dict
def update_settings(default_settings: dict, user_settings: dict):
# pylint: disable=too-many-branches
# merge everything except the engines
for k, v in user_settings.items():
if k not in ('use_default_settings', 'engines'):
if k in default_settings and isinstance(v, Mapping):
update_dict(default_settings[k], v)
else:
default_settings[k] = v
categories_as_tabs = user_settings.get('categories_as_tabs')
if categories_as_tabs:
default_settings['categories_as_tabs'] = categories_as_tabs
# parse the engines
remove_engines = None
keep_only_engines = None
use_default_settings = user_settings.get('use_default_settings')
if isinstance(use_default_settings, dict):
remove_engines = use_default_settings.get('engines', {}).get('remove')
keep_only_engines = use_default_settings.get('engines', {}).get('keep_only')
if 'engines' in user_settings or remove_engines is not None or keep_only_engines is not None:
engines = default_settings['engines']
# parse "use_default_settings.engines.remove"
if remove_engines is not None:
engines = list(filterfalse(lambda engine: (engine.get('name')) in remove_engines, engines))
# parse "use_default_settings.engines.keep_only"
if keep_only_engines is not None:
engines = list(filter(lambda engine: (engine.get('name')) in keep_only_engines, engines))
# parse "engines"
user_engines = user_settings.get('engines')
if user_engines:
engines_dict = dict((definition['name'], definition) for definition in engines)
for user_engine in user_engines:
default_engine = engines_dict.get(user_engine['name'])
if default_engine:
update_dict(default_engine, user_engine)
else:
engines.append(user_engine)
# store the result
default_settings['engines'] = engines
return default_settings
def is_use_default_settings(user_settings):
use_default_settings = user_settings.get('use_default_settings')
if use_default_settings is True:
return True
if isinstance(use_default_settings, dict):
return True
if use_default_settings is False or use_default_settings is None:
return False
raise ValueError('Invalid value for use_default_settings')
def load_settings(load_user_settings=True) -> tuple[dict, str]:
"""Function for loading the settings of the SearXNG application
(:ref:`settings.yml <searxng settings.yml>`)."""
msg = f"load the default settings from {DEFAULT_SETTINGS_FILE}"
cfg = load_yaml(DEFAULT_SETTINGS_FILE)
cfg_folder = get_user_cfg_folder()
if not load_user_settings or not cfg_folder:
return cfg, msg
settings_yml = os.environ.get("SEARXNG_SETTINGS_PATH")
if settings_yml and Path(settings_yml).is_file():
# see get_user_cfg_folder() --> SEARXNG_SETTINGS_PATH points to a file
settings_yml = Path(settings_yml).name
else:
# see get_user_cfg_folder() --> SEARXNG_SETTINGS_PATH points to a folder
settings_yml = SETTINGS_YAML
cfg_file = cfg_folder / settings_yml
if not cfg_file.exists():
return cfg, msg
msg = f"load the user settings from {cfg_file}"
user_cfg = load_yaml(cfg_file)
if is_use_default_settings(user_cfg):
# the user settings are merged with the default configuration
msg = f"merge the default settings ( {DEFAULT_SETTINGS_FILE} ) and the user settings ( {cfg_file} )"
update_settings(cfg, user_cfg)
else:
cfg = user_cfg
return cfg, msg