[enh] settings.yml: add use_default_settings option (2nd version)

searx/settings_loader.py

@@ -0,0 +1,129 @@
+# SPDX-License-Identifier: AGPL-3.0-or-later
+
+from os import environ
+from os.path import dirname, join, abspath, isfile
+from collections.abc import Mapping
+from itertools import filterfalse
+
+import yaml
+
+from searx.exceptions import SearxSettingsException
+
+
+searx_dir = abspath(dirname(__file__))
+
+
+def check_settings_yml(file_name):
+    if isfile(file_name):
+        return file_name
+    return None
+
+
+def load_yaml(file_name):
+    try:
+        with open(file_name, 'r', encoding='utf-8') as settings_yaml:
+            return yaml.safe_load(settings_yaml)
+    except IOError as e:
+        raise SearxSettingsException(e, file_name)
+    except yaml.YAMLError as e:
+        raise SearxSettingsException(e, file_name)
+
+
+def get_default_settings_path():
+    return check_settings_yml(join(searx_dir, 'settings.yml'))
+
+
+def get_user_settings_path():
+    # find location of settings.yml
+    if 'SEARX_SETTINGS_PATH' in environ:
+        # if possible set path to settings using the
+        # enviroment variable SEARX_SETTINGS_PATH
+        return check_settings_yml(environ['SEARX_SETTINGS_PATH'])
+
+    # if not, get it from searx code base or last solution from /etc/searx
+    return check_settings_yml('/etc/searx/settings.yml')
+
+
+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, user_settings):
+    # merge everything except the engines
+    for k, v in user_settings.items():
+        if k not in ('use_default_settings', 'engines'):
+            update_dict(default_settings[k], v)
+
+    # 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_setttings=True):
+    default_settings_path = get_default_settings_path()
+    user_settings_path = get_user_settings_path()
+    if user_settings_path is None or not load_user_setttings:
+        # no user settings
+        return (load_yaml(default_settings_path),
+                'load the default settings from {}'.format(default_settings_path))
+
+    # user settings
+    user_settings = load_yaml(user_settings_path)
+    if is_use_default_settings(user_settings):
+        # the user settings are merged with the default configuration
+        default_settings = load_yaml(default_settings_path)
+        update_settings(default_settings, user_settings)
+        return (default_settings,
+                'merge the default settings ( {} ) and the user setttings ( {} )'
+                .format(default_settings_path, user_settings_path))
+
+    # the user settings, fully replace the default configuration
+    return (user_settings,
+            'load the user settings from {}'.format(user_settings_path))