The checker requires Redis

Remove the abstraction in searx.shared.SharedDict.
Implement a basic and dedicated scheduler for the checker using a Redis script.

searx/shared/__init__.py

@@ -1,39 +1,6 @@
 # SPDX-License-Identifier: AGPL-3.0-or-later
+# lint: pylint
+"""Initialization of a *shared* storage.
+"""
 
-import logging
-import importlib
-
-logger = logging.getLogger('searx.shared')
-
-__all__ = ['SharedDict', 'schedule']
-
-try:
-    uwsgi = importlib.import_module('uwsgi')
-except:
-    # no uwsgi
-    from .shared_simple import SimpleSharedDict as SharedDict, schedule
-
-    logger.info('Use shared_simple implementation')
-else:
-    try:
-        uwsgi.cache_update('dummy', b'dummy')
-        if uwsgi.cache_get('dummy') != b'dummy':
-            raise Exception()
-    except:
-        # uwsgi.ini configuration problem: disable all scheduling
-        logger.error(
-            'uwsgi.ini configuration error, add this line to your uwsgi.ini\n'
-            'cache2 = name=searxngcache,items=2000,blocks=2000,blocksize=4096,bitmap=1'
-        )
-        from .shared_simple import SimpleSharedDict as SharedDict
-
-        def schedule(delay, func, *args):
-            return False
-
-    else:
-        # uwsgi
-        from .shared_uwsgi import UwsgiCacheSharedDict as SharedDict, schedule
-
-        logger.info('Use shared_uwsgi implementation')
-
-storage = SharedDict()
+from . import redisdb

searx/shared/redisdb.py

@@ -26,26 +26,20 @@ import redis
 from searx import get_setting
 
 
-logger = logging.getLogger('searx.shared.redis')
+logger = logging.getLogger('searx.shared.redisdb')
 _client = None
 
 
-def client():
-    global _client  # pylint: disable=global-statement
-    if _client is None:
-        # not thread safe: in the worst case scenario, two or more clients are
-        # initialized only one is kept, the others are garbage collected.
-        _client = redis.Redis.from_url(get_setting('redis.url'))
+def client() -> redis.Redis:
     return _client
 
 
-def init():
+def initialize():
+    global _client  # pylint: disable=global-statement
     try:
-        c = client()
-        logger.info("connected redis DB --> %s", c.acl_whoami())
-        return True
+        _client = redis.Redis.from_url(get_setting('redis.url'))
+        logger.info("connected redis: %s", get_setting('redis.url'))
     except redis.exceptions.ConnectionError as exc:
         _pw = pwd.getpwuid(os.getuid())
         logger.error("[%s (%s)] can't connect redis DB ...", _pw.pw_name, _pw.pw_uid)
         logger.error("  %s", exc)
-    return False

searx/shared/shared_abstract.py

@@ -1,22 +0,0 @@
-# SPDX-License-Identifier: AGPL-3.0-or-later
-# pyright: strict
-from abc import ABC, abstractmethod
-from typing import Optional
-
-
-class SharedDict(ABC):
-    @abstractmethod
-    def get_int(self, key: str) -> Optional[int]:
-        pass
-
-    @abstractmethod
-    def set_int(self, key: str, value: int):
-        pass
-
-    @abstractmethod
-    def get_str(self, key: str) -> Optional[str]:
-        pass
-
-    @abstractmethod
-    def set_str(self, key: str, value: str):
-        pass

searx/shared/shared_simple.py

@@ -1,40 +0,0 @@
-# SPDX-License-Identifier: AGPL-3.0-or-later
-
-import threading
-from typing import Optional
-
-from . import shared_abstract
-
-
-class SimpleSharedDict(shared_abstract.SharedDict):
-
-    __slots__ = ('d',)
-
-    def __init__(self):
-        self.d = {}
-
-    def get_int(self, key: str) -> Optional[int]:
-        return self.d.get(key, None)
-
-    def set_int(self, key: str, value: int):
-        self.d[key] = value
-
-    def get_str(self, key: str) -> Optional[str]:
-        return self.d.get(key, None)
-
-    def set_str(self, key: str, value: str):
-        self.d[key] = value
-
-
-def schedule(delay, func, *args):
-    def call_later():
-        t = threading.Timer(delay, wrapper)
-        t.daemon = True
-        t.start()
-
-    def wrapper():
-        call_later()
-        func(*args)
-
-    call_later()
-    return True

searx/shared/shared_uwsgi.py

@@ -1,64 +0,0 @@
-# SPDX-License-Identifier: AGPL-3.0-or-later
-
-import time
-from typing import Optional
-import uwsgi  # pyright: ignore # pylint: disable=E0401
-from . import shared_abstract
-
-
-_last_signal = 10
-
-
-class UwsgiCacheSharedDict(shared_abstract.SharedDict):
-    def get_int(self, key: str) -> Optional[int]:
-        value = uwsgi.cache_get(key)
-        if value is None:
-            return value
-        else:
-            return int.from_bytes(value, 'big')
-
-    def set_int(self, key: str, value: int):
-        b = value.to_bytes(4, 'big')
-        uwsgi.cache_update(key, b)
-
-    def get_str(self, key: str) -> Optional[str]:
-        value = uwsgi.cache_get(key)
-        if value is None:
-            return value
-        else:
-            return value.decode('utf-8')
-
-    def set_str(self, key: str, value: str):
-        b = value.encode('utf-8')
-        uwsgi.cache_update(key, b)
-
-
-def schedule(delay, func, *args):
-    """
-    Can be implemented using a spooler.
-    https://uwsgi-docs.readthedocs.io/en/latest/PythonDecorators.html
-
-    To make the uwsgi configuration simple, use the alternative implementation.
-    """
-    global _last_signal
-
-    def sighandler(signum):
-        now = int(time.time())
-        key = 'scheduler_call_time_signal_' + str(signum)
-        uwsgi.lock()
-        try:
-            updating = uwsgi.cache_get(key)
-            if updating is not None:
-                updating = int.from_bytes(updating, 'big')
-                if now - updating < delay:
-                    return
-            uwsgi.cache_update(key, now.to_bytes(4, 'big'))
-        finally:
-            uwsgi.unlock()
-        func(*args)
-
-    signal_num = _last_signal
-    _last_signal += 1
-    uwsgi.register_signal(signal_num, 'worker', sighandler)
-    uwsgi.add_timer(signal_num, delay)
-    return True