searxng/searx/plugins/__init__.py
Alexandre Flament 2b4fef7118 plugins: refactor initialization
add a new function "init" call when the app starts.
The function can:
* return False to disable the plugin.
* modify the Flask app.
2021-10-06 19:18:19 +02:00

252 lines
7.9 KiB
Python

# SPDX-License-Identifier: AGPL-3.0-or-later
# lint: pylint
# pylint: disable=missing-module-docstring, missing-class-docstring
import sys
from hashlib import sha256
from importlib import import_module
from os import listdir, makedirs, remove, stat, utime
from os.path import abspath, basename, dirname, exists, join
from shutil import copyfile
from pkgutil import iter_modules
from logging import getLogger
from searx import logger, settings
logger = logger.getChild("plugins")
required_attrs = (
("name", str),
("description", str),
("default_on", bool)
)
optional_attrs = (
("js_dependencies", tuple),
("css_dependencies", tuple),
("preference_section", str),
)
def sha_sum(filename):
with open(filename, "rb") as f:
file_content_bytes = f.read()
return sha256(file_content_bytes).hexdigest()
def sync_resource(base_path, resource_path, name, target_dir, plugin_dir):
dep_path = join(base_path, resource_path)
file_name = basename(dep_path)
resource_path = join(target_dir, file_name)
if not exists(resource_path) or sha_sum(dep_path) != sha_sum(resource_path):
try:
copyfile(dep_path, resource_path)
# copy atime_ns and mtime_ns, so the weak ETags (generated by
# the HTTP server) do not change
dep_stat = stat(dep_path)
utime(resource_path, ns=(dep_stat.st_atime_ns, dep_stat.st_mtime_ns))
except IOError:
logger.critical(
"failed to copy plugin resource {0} for plugin {1}".format(
file_name, name
)
)
sys.exit(3)
# returning with the web path of the resource
return join("plugins/external_plugins", plugin_dir, file_name)
def prepare_package_resources(plugin, plugin_module_name):
# pylint: disable=consider-using-generator
plugin_base_path = dirname(abspath(plugin.__file__))
plugin_dir = plugin_module_name
target_dir = join(
settings["ui"]["static_path"], "plugins/external_plugins", plugin_dir
)
try:
makedirs(target_dir, exist_ok=True)
except IOError:
logger.critical(
"failed to create resource directory {0} for plugin {1}".format(
target_dir, plugin_module_name
)
)
sys.exit(3)
resources = []
if hasattr(plugin, "js_dependencies"):
resources.extend(map(basename, plugin.js_dependencies))
plugin.js_dependencies = tuple(
[
sync_resource(
plugin_base_path, x, plugin_module_name, target_dir, plugin_dir
)
for x in plugin.js_dependencies
]
)
if hasattr(plugin, "css_dependencies"):
resources.extend(map(basename, plugin.css_dependencies))
plugin.css_dependencies = tuple(
[
sync_resource(
plugin_base_path, x, plugin_module_name, target_dir, plugin_dir
)
for x in plugin.css_dependencies
]
)
for f in listdir(target_dir):
if basename(f) not in resources:
resource_path = join(target_dir, basename(f))
try:
remove(resource_path)
except IOError:
logger.critical(
"failed to remove unused resource file {0} for plugin {1}".format(
resource_path, plugin_module_name
)
)
sys.exit(3)
def load_plugin(plugin_module_name, external):
# pylint: disable=too-many-branches
try:
plugin = import_module(plugin_module_name)
except (
SyntaxError,
KeyboardInterrupt,
SystemExit,
SystemError,
ImportError,
RuntimeError,
) as e:
logger.critical("%s: fatal exception", plugin_module_name, exc_info=e)
sys.exit(3)
except BaseException:
logger.exception("%s: exception while loading, the plugin is disabled", plugin_module_name)
return None
# difference with searx: use module name instead of the user name
plugin.id = plugin_module_name
#
plugin.logger = getLogger(plugin_module_name)
for plugin_attr, plugin_attr_type in required_attrs:
if not hasattr(plugin, plugin_attr):
logger.critical(
'%s: missing attribute "%s", cannot load plugin', plugin, plugin_attr
)
sys.exit(3)
attr = getattr(plugin, plugin_attr)
if not isinstance(attr, plugin_attr_type):
type_attr = str(type(attr))
logger.critical(
'{1}: attribute "{0}" is of type {2}, must be of type {3}, cannot load plugin'.format(
plugin, plugin_attr, type_attr, plugin_attr_type
)
)
sys.exit(3)
for plugin_attr, plugin_attr_type in optional_attrs:
if not hasattr(plugin, plugin_attr) or not isinstance(
getattr(plugin, plugin_attr), plugin_attr_type
):
setattr(plugin, plugin_attr, plugin_attr_type())
if not hasattr(plugin, "preference_section"):
plugin.preference_section = "general"
# query plugin
if plugin.preference_section == "query":
for plugin_attr in ("query_keywords", "query_examples"):
if not hasattr(plugin, plugin_attr):
logger.critical(
'missing attribute "{0}", cannot load plugin: {1}'.format(
plugin_attr, plugin
)
)
sys.exit(3)
if settings.get("enabled_plugins"):
# searx compatibility: plugin.name in settings['enabled_plugins']
plugin.default_on = (
plugin.name in settings["enabled_plugins"]
or plugin.id in settings["enabled_plugins"]
)
# copy ressources if this is an external plugin
if external:
prepare_package_resources(plugin, plugin_module_name)
logger.debug("%s: loaded", plugin_module_name)
return plugin
def load_and_initialize_plugin(plugin_module_name, external, init_args):
plugin = load_plugin(plugin_module_name, external)
if plugin and hasattr(plugin, 'init'):
try:
return plugin if plugin.init(*init_args) else None
except Exception: # pylint: disable=broad-except
plugin.logger.exception(
"Exception while calling init, the plugin is disabled"
)
return None
return plugin
class PluginStore:
def __init__(self):
self.plugins = []
def __iter__(self):
for plugin in self.plugins:
yield plugin
def register(self, plugin):
self.plugins.append(plugin)
def call(self, ordered_plugin_list, plugin_type, *args, **kwargs):
# pylint: disable=no-self-use
ret = True
for plugin in ordered_plugin_list:
if hasattr(plugin, plugin_type):
try:
ret = getattr(plugin, plugin_type)(*args, **kwargs)
if not ret:
break
except Exception: # pylint: disable=broad-except
plugin.logger.exception("Exception while calling %s", plugin_type)
return ret
plugins = PluginStore()
def plugin_module_names():
yield_plugins = set()
# embedded plugins
for module_name in iter_modules(path=[dirname(__file__)]):
yield (module_name, False)
yield_plugins.add(module_name)
# external plugins
for module_name in settings['plugins']:
if module_name not in yield_plugins:
yield (module_name, True)
yield_plugins.add(module_name)
def initialize(app):
for module_name, external in plugin_module_names():
plugin = load_and_initialize_plugin(__name__ + "." + module_name.name, external, (app, settings))
if plugin:
plugins.register(plugin)