# SPDX-License-Identifier: AGPL-3.0-or-later
"""Abstract base classes for engine request processors.
"""
import threading
from abc import abstractmethod, ABC
from timeit import default_timer
from typing import Dict, Union
from searx import settings, logger
from searx.engines import engines
from searx.network import get_time_for_thread, get_network
from searx.metrics import histogram_observe, counter_inc, count_exception, count_error
from searx.exceptions import SearxEngineAccessDeniedException, SearxEngineResponseException
from searx.utils import get_engine_from_settings
logger = logger.getChild('searx.search.processor')
SUSPENDED_STATUS: Dict[Union[int, str], 'SuspendedStatus'] = {}
[docs]
class SuspendedStatus:
"""Class to handle suspend state."""
__slots__ = 'suspend_end_time', 'suspend_reason', 'continuous_errors', 'lock'
def __init__(self):
self.lock = threading.Lock()
self.continuous_errors = 0
self.suspend_end_time = 0
self.suspend_reason = None
@property
def is_suspended(self):
return self.suspend_end_time >= default_timer()
def suspend(self, suspended_time, suspend_reason):
with self.lock:
# update continuous_errors / suspend_end_time
self.continuous_errors += 1
if suspended_time is None:
suspended_time = min(
settings['search']['max_ban_time_on_fail'],
self.continuous_errors * settings['search']['ban_time_on_fail'],
)
self.suspend_end_time = default_timer() + suspended_time
self.suspend_reason = suspend_reason
logger.debug('Suspend for %i seconds', suspended_time)
def resume(self):
with self.lock:
# reset the suspend variables
self.continuous_errors = 0
self.suspend_end_time = 0
self.suspend_reason = None
[docs]
class EngineProcessor(ABC):
"""Base classes used for all types of request processors."""
__slots__ = 'engine', 'engine_name', 'lock', 'suspended_status', 'logger'
def __init__(self, engine, engine_name: str):
self.engine = engine
self.engine_name = engine_name
self.logger = engines[engine_name].logger
key = get_network(self.engine_name)
key = id(key) if key else self.engine_name
self.suspended_status = SUSPENDED_STATUS.setdefault(key, SuspendedStatus())
def initialize(self):
try:
self.engine.init(get_engine_from_settings(self.engine_name))
except SearxEngineResponseException as exc:
self.logger.warning('Fail to initialize // %s', exc)
except Exception: # pylint: disable=broad-except
self.logger.exception('Fail to initialize')
else:
self.logger.debug('Initialized')
@property
def has_initialize_function(self):
return hasattr(self.engine, 'init')
def handle_exception(self, result_container, exception_or_message, suspend=False):
# update result_container
if isinstance(exception_or_message, BaseException):
exception_class = exception_or_message.__class__
module_name = getattr(exception_class, '__module__', 'builtins')
module_name = '' if module_name == 'builtins' else module_name + '.'
error_message = module_name + exception_class.__qualname__
else:
error_message = exception_or_message
result_container.add_unresponsive_engine(self.engine_name, error_message)
# metrics
counter_inc('engine', self.engine_name, 'search', 'count', 'error')
if isinstance(exception_or_message, BaseException):
count_exception(self.engine_name, exception_or_message)
else:
count_error(self.engine_name, exception_or_message)
# suspend the engine ?
if suspend:
suspended_time = None
if isinstance(exception_or_message, SearxEngineAccessDeniedException):
suspended_time = exception_or_message.suspended_time
self.suspended_status.suspend(suspended_time, error_message) # pylint: disable=no-member
def _extend_container_basic(self, result_container, start_time, search_results):
# update result_container
result_container.extend(self.engine_name, search_results)
engine_time = default_timer() - start_time
page_load_time = get_time_for_thread()
result_container.add_timing(self.engine_name, engine_time, page_load_time)
# metrics
counter_inc('engine', self.engine_name, 'search', 'count', 'successful')
histogram_observe(engine_time, 'engine', self.engine_name, 'time', 'total')
if page_load_time is not None:
histogram_observe(page_load_time, 'engine', self.engine_name, 'time', 'http')
def extend_container(self, result_container, start_time, search_results):
if getattr(threading.current_thread(), '_timeout', False):
# the main thread is not waiting anymore
self.handle_exception(result_container, 'timeout', None)
else:
# check if the engine accepted the request
if search_results is not None:
self._extend_container_basic(result_container, start_time, search_results)
self.suspended_status.resume()
def extend_container_if_suspended(self, result_container):
if self.suspended_status.is_suspended:
result_container.add_unresponsive_engine(
self.engine_name, self.suspended_status.suspend_reason, suspended=True
)
return True
return False
[docs]
def get_params(self, search_query, engine_category):
"""Returns a set of (see :ref:`request params <engine request arguments>`) or
``None`` if request is not supported.
Not supported conditions (``None`` is returned):
- A page-number > 1 when engine does not support paging.
- A time range when the engine does not support time range.
"""
# if paging is not supported, skip
if search_query.pageno > 1 and not self.engine.paging:
return None
# if max page is reached, skip
max_page = self.engine.max_page or settings['search']['max_page']
if max_page and max_page < search_query.pageno:
return None
# if time_range is not supported, skip
if search_query.time_range and not self.engine.time_range_support:
return None
params = {}
params['category'] = engine_category
params['pageno'] = search_query.pageno
params['safesearch'] = search_query.safesearch
params['time_range'] = search_query.time_range
params['engine_data'] = search_query.engine_data.get(self.engine_name, {})
params['searxng_locale'] = search_query.lang
# deprecated / vintage --> use params['searxng_locale']
#
# Conditions related to engine's traits are implemented in engine.traits
# module. Don't do 'locale' decisions here in the abstract layer of the
# search processor, just pass the value from user's choice unchanged to
# the engine request.
if hasattr(self.engine, 'language') and self.engine.language:
params['language'] = self.engine.language
else:
params['language'] = search_query.lang
return params
@abstractmethod
def search(self, query, params, result_container, start_time, timeout_limit):
pass
def get_tests(self):
tests = getattr(self.engine, 'tests', None)
if tests is None:
tests = getattr(self.engine, 'additional_tests', {})
tests.update(self.get_default_tests())
return tests
def get_default_tests(self):
return {}
