[mod] migrate from Redis to Valkey (#4795)

This patch migrates from `redis==5.2.1` [1] to `valkey==6.1.0` [2].

The migration to valkey is necessary because the company behind Redis has decided
to abandon the open source license. After experiencing a drop in user numbers,
they now want to run it under a dual license again. But this move demonstrates
once again how unreliable the company is and how it treats open source
developers.

To review first, read the docs::

    $ make docs.live

Follow the instructions to remove redis:

- http://0.0.0.0:8000/admin/settings/settings_redis.html

Config and install a local valkey DB:

- http://0.0.0.0:8000/admin/settings/settings_valkey.html

[1] https://pypi.org/project/redis/
[2] https://pypi.org/project/valkey/

Co-authored-by: HLFH <gaspard@dhautefeuille.eu>
Co-authored-by: Markus Heiser <markus.heiser@darmarit.de>

14 files changed, 198 insertions, 197 deletions

diff --git a/searx/botdetection/__init__.py b/searx/botdetection/__init__.py
index 51f437cf0..4079d97a9 100644
--- a/searx/botdetection/__init__.py
+++ b/searx/botdetection/__init__.py
@@ -12,11 +12,11 @@ from ._helpers import too_many_requests
 
 __all__ = ['dump_request', 'get_network', 'get_real_ip', 'too_many_requests']
 
-redis_client = None
+valkey_client = None
 cfg = None
 
 
-def init(_cfg, _redis_client):
-    global redis_client, cfg  # pylint: disable=global-statement
-    redis_client = _redis_client
+def init(_cfg, _valkey_client):
+    global valkey_client, cfg  # pylint: disable=global-statement
+    valkey_client = _valkey_client
     cfg = _cfg
diff --git a/searx/botdetection/ip_limit.py b/searx/botdetection/ip_limit.py
index 161a9826e..93af8b7c5 100644
--- a/searx/botdetection/ip_limit.py
+++ b/searx/botdetection/ip_limit.py
@@ -6,8 +6,8 @@ Method ``ip_limit``
 
 The ``ip_limit`` method counts request from an IP in *sliding windows*.  If
 there are to many requests in a sliding window, the request is evaluated as a
-bot request.  This method requires a redis DB and needs a HTTP X-Forwarded-For_
-header.  To take privacy only the hash value of an IP is stored in the redis DB
+bot request.  This method requires a valkey DB and needs a HTTP X-Forwarded-For_
+header.  To take privacy only the hash value of an IP is stored in the valkey DB
 and at least for a maximum of 10 minutes.
 
 The :py:obj:`.link_token` method can be used to investigate whether a request is
@@ -46,8 +46,8 @@ import flask
 import werkzeug
 
 from searx.extended_types import SXNG_Request
-from searx import redisdb
-from searx.redislib import incr_sliding_window, drop_counter
+from searx import valkeydb
+from searx.valkeylib import incr_sliding_window, drop_counter
 
 from . import link_token
 from . import config
@@ -97,14 +97,14 @@ def filter_request(
 ) -> werkzeug.Response | None:
 
     # pylint: disable=too-many-return-statements
-    redis_client = redisdb.client()
+    valkey_client = valkeydb.client()
 
     if network.is_link_local and not cfg['botdetection.ip_limit.filter_link_local']:
         logger.debug("network %s is link-local -> not monitored by ip_limit method", network.compressed)
         return None
 
     if request.args.get('format', 'html') != 'html':
-        c = incr_sliding_window(redis_client, 'ip_limit.API_WINDOW:' + network.compressed, API_WINDOW)
+        c = incr_sliding_window(valkey_client, 'ip_limit.API_WINDOW:' + network.compressed, API_WINDOW)
         if c > API_MAX:
             return too_many_requests(network, "too many request in API_WINDOW")
 
@@ -114,12 +114,12 @@ def filter_request(
 
         if not suspicious:
             # this IP is no longer suspicious: release ip again / delete the counter of this IP
-            drop_counter(redis_client, 'ip_limit.SUSPICIOUS_IP_WINDOW' + network.compressed)
+            drop_counter(valkey_client, 'ip_limit.SUSPICIOUS_IP_WINDOW' + network.compressed)
             return None
 
         # this IP is suspicious: count requests from this IP
         c = incr_sliding_window(
-            redis_client, 'ip_limit.SUSPICIOUS_IP_WINDOW' + network.compressed, SUSPICIOUS_IP_WINDOW
+            valkey_client, 'ip_limit.SUSPICIOUS_IP_WINDOW' + network.compressed, SUSPICIOUS_IP_WINDOW
         )
         if c > SUSPICIOUS_IP_MAX:
             logger.error("BLOCK: too many request from %s in SUSPICIOUS_IP_WINDOW (redirect to /)", network)
@@ -127,22 +127,22 @@ def filter_request(
             response.headers["Cache-Control"] = "no-store, max-age=0"
             return response
 
-        c = incr_sliding_window(redis_client, 'ip_limit.BURST_WINDOW' + network.compressed, BURST_WINDOW)
+        c = incr_sliding_window(valkey_client, 'ip_limit.BURST_WINDOW' + network.compressed, BURST_WINDOW)
         if c > BURST_MAX_SUSPICIOUS:
             return too_many_requests(network, "too many request in BURST_WINDOW (BURST_MAX_SUSPICIOUS)")
 
-        c = incr_sliding_window(redis_client, 'ip_limit.LONG_WINDOW' + network.compressed, LONG_WINDOW)
+        c = incr_sliding_window(valkey_client, 'ip_limit.LONG_WINDOW' + network.compressed, LONG_WINDOW)
         if c > LONG_MAX_SUSPICIOUS:
             return too_many_requests(network, "too many request in LONG_WINDOW (LONG_MAX_SUSPICIOUS)")
 
         return None
 
     # vanilla limiter without extensions counts BURST_MAX and LONG_MAX
-    c = incr_sliding_window(redis_client, 'ip_limit.BURST_WINDOW' + network.compressed, BURST_WINDOW)
+    c = incr_sliding_window(valkey_client, 'ip_limit.BURST_WINDOW' + network.compressed, BURST_WINDOW)
     if c > BURST_MAX:
         return too_many_requests(network, "too many request in BURST_WINDOW (BURST_MAX)")
 
-    c = incr_sliding_window(redis_client, 'ip_limit.LONG_WINDOW' + network.compressed, LONG_WINDOW)
+    c = incr_sliding_window(valkey_client, 'ip_limit.LONG_WINDOW' + network.compressed, LONG_WINDOW)
     if c > LONG_MAX:
         return too_many_requests(network, "too many request in LONG_WINDOW (LONG_MAX)")
 
diff --git a/searx/botdetection/link_token.py b/searx/botdetection/link_token.py
index c255790cb..600796380 100644
--- a/searx/botdetection/link_token.py
+++ b/searx/botdetection/link_token.py
@@ -10,7 +10,7 @@ a ping by request a static URL.
 
 .. note::
 
-   This method requires a redis DB and needs a HTTP X-Forwarded-For_ header.
+   This method requires a valkey DB and needs a HTTP X-Forwarded-For_ header.
 
 To get in use of this method a flask URL route needs to be added:
 
@@ -45,8 +45,8 @@ import string
 import random
 
 from searx import logger
-from searx import redisdb
-from searx.redislib import secret_hash
+from searx import valkeydb
+from searx.valkeylib import secret_hash
 from searx.extended_types import SXNG_Request
 
 from ._helpers import (
@@ -76,17 +76,17 @@ def is_suspicious(network: IPv4Network | IPv6Network, request: SXNG_Request, ren
     :py:obj:`PING_LIVE_TIME`.
 
     """
-    redis_client = redisdb.client()
-    if not redis_client:
+    valkey_client = valkeydb.client()
+    if not valkey_client:
         return False
 
     ping_key = get_ping_key(network, request)
-    if not redis_client.get(ping_key):
+    if not valkey_client.get(ping_key):
         logger.info("missing ping (IP: %s) / request: %s", network.compressed, ping_key)
         return True
 
     if renew:
-        redis_client.set(ping_key, 1, ex=PING_LIVE_TIME)
+        valkey_client.set(ping_key, 1, ex=PING_LIVE_TIME)
 
     logger.debug("found ping for (client) network %s -> %s", network.compressed, ping_key)
     return False
@@ -98,9 +98,9 @@ def ping(request: SXNG_Request, token: str):
     The expire time of this ping-key is :py:obj:`PING_LIVE_TIME`.
 
     """
-    from . import redis_client, cfg  # pylint: disable=import-outside-toplevel, cyclic-import
+    from . import valkey_client, cfg  # pylint: disable=import-outside-toplevel, cyclic-import
 
-    if not redis_client:
+    if not valkey_client:
         return
     if not token_is_valid(token):
         return
@@ -110,7 +110,7 @@ def ping(request: SXNG_Request, token: str):
 
     ping_key = get_ping_key(network, request)
     logger.debug("store ping_key for (client) network %s (IP %s) -> %s", network.compressed, real_ip, ping_key)
-    redis_client.set(ping_key, 1, ex=PING_LIVE_TIME)
+    valkey_client.set(ping_key, 1, ex=PING_LIVE_TIME)
 
 
 def get_ping_key(network: IPv4Network | IPv6Network, request: SXNG_Request) -> str:
@@ -134,21 +134,21 @@ def token_is_valid(token) -> bool:
 
 def get_token() -> str:
     """Returns current token.  If there is no currently active token a new token
-    is generated randomly and stored in the redis DB.
+    is generated randomly and stored in the valkey DB.
 
     - :py:obj:`TOKEN_LIVE_TIME`
     - :py:obj:`TOKEN_KEY`
 
     """
-    redis_client = redisdb.client()
-    if not redis_client:
-        # This function is also called when limiter is inactive / no redis DB
+    valkey_client = valkeydb.client()
+    if not valkey_client:
+        # This function is also called when limiter is inactive / no valkey DB
         # (see render function in webapp.py)
         return '12345678'
-    token = redis_client.get(TOKEN_KEY)
+    token = valkey_client.get(TOKEN_KEY)
     if token:
         token = token.decode('UTF-8')
     else:
         token = ''.join(random.choice(string.ascii_lowercase + string.digits) for _ in range(16))
-        redis_client.set(TOKEN_KEY, token, ex=TOKEN_LIVE_TIME)
+        valkey_client.set(TOKEN_KEY, token, ex=TOKEN_LIVE_TIME)
     return token
diff --git a/searx/engines/redis_server.py b/searx/engines/valkey_server.py
index eebb5809b..b2d3dd26f 100644
--- a/searx/engines/redis_server.py
+++ b/searx/engines/valkey_server.py
@@ -1,7 +1,7 @@
 # SPDX-License-Identifier: AGPL-3.0-or-later
-"""Redis is an open source (BSD licensed), in-memory data structure (key value
-based) store.  Before configuring the ``redis_server`` engine, you must install
-the dependency redis_.
+"""Valkey is an open source (BSD licensed), in-memory data structure (key value
+based) store.  Before configuring the ``valkey_server`` engine, you must install
+the dependency valkey_.
 
 Configuration
 =============
@@ -17,11 +17,11 @@ Below is an example configuration:
 
 .. code:: yaml
 
-  # Required dependency: redis
+  # Required dependency: valkey
 
-  - name: myredis
+  - name: myvalkey
     shortcut : rds
-    engine: redis_server
+    engine: valkey_server
     exact_match_only: false
     host: '127.0.0.1'
     port: 6379
@@ -34,13 +34,13 @@ Implementations
 
 """
 
-import redis  # pylint: disable=import-error
+import valkey  # pylint: disable=import-error
 
 from searx.result_types import EngineResults
 
 engine_type = 'offline'
 
-# redis connection variables
+# valkey connection variables
 host = '127.0.0.1'
 port = 6379
 password = ''
@@ -50,12 +50,12 @@ db = 0
 paging = False
 exact_match_only = True
 
-_redis_client = None
+_valkey_client = None
 
 
 def init(_engine_settings):
-    global _redis_client  # pylint: disable=global-statement
-    _redis_client = redis.StrictRedis(
+    global _valkey_client  # pylint: disable=global-statement
+    _valkey_client = valkey.StrictValkey(
         host=host,
         port=port,
         db=db,
@@ -72,28 +72,28 @@ def search(query, _params) -> EngineResults:
             res.add(res.types.KeyValue(kvmap=kvmap))
         return res
 
-    kvmap: dict[str, str] = _redis_client.hgetall(query)
+    kvmap: dict[str, str] = _valkey_client.hgetall(query)
     if kvmap:
         res.add(res.types.KeyValue(kvmap=kvmap))
     elif " " in query:
         qset, rest = query.split(" ", 1)
-        for row in _redis_client.hscan_iter(qset, match='*{}*'.format(rest)):
+        for row in _valkey_client.hscan_iter(qset, match='*{}*'.format(rest)):
             res.add(res.types.KeyValue(kvmap={row[0]: row[1]}))
     return res
 
 
 def search_keys(query) -> list[dict]:
     ret = []
-    for key in _redis_client.scan_iter(match='*{}*'.format(query)):
-        key_type = _redis_client.type(key)
+    for key in _valkey_client.scan_iter(match='*{}*'.format(query)):
+        key_type = _valkey_client.type(key)
         res = None
 
         if key_type == 'hash':
-            res = _redis_client.hgetall(key)
+            res = _valkey_client.hgetall(key)
         elif key_type == 'list':
-            res = dict(enumerate(_redis_client.lrange(key, 0, -1)))
+            res = dict(enumerate(_valkey_client.lrange(key, 0, -1)))
 
         if res:
-            res['redis_key'] = key
+            res['valkey_key'] = key
             ret.append(res)
     return ret
diff --git a/searx/limiter.py b/searx/limiter.py
index 92b38c68f..99bc338d1 100644
--- a/searx/limiter.py
+++ b/searx/limiter.py
@@ -17,7 +17,7 @@ from the :ref:`botdetection`:
   the time.
 
 - Detection & dynamically :ref:`botdetection rate limit` of bots based on the
-  behavior of the requests.  For dynamically changeable IP lists a Redis
+  behavior of the requests.  For dynamically changeable IP lists a Valkey
   database is needed.
 
 The prerequisite for IP based methods is the correct determination of the IP of
@@ -50,13 +50,13 @@ To enable the limiter activate:
      ...
      limiter: true  # rate limit the number of request on the instance, block some bots
 
-and set the redis-url connection. Check the value, it depends on your redis DB
-(see :ref:`settings redis`), by example:
+and set the valkey-url connection. Check the value, it depends on your valkey DB
+(see :ref:`settings valkey`), by example:
 
 .. code:: yaml
 
-   redis:
-     url: unix:///usr/local/searxng-redis/run/redis.sock?db=0
+   valkey:
+     url: valkey://localhost:6379/0
 
 
 Configure Limiter
@@ -102,7 +102,7 @@ import werkzeug
 
 from searx import (
     logger,
-    redisdb,
+    valkeydb,
 )
 from searx import botdetection
 from searx.extended_types import SXNG_Request, sxng_request
@@ -217,7 +217,7 @@ def pre_request():
 
 
 def is_installed():
-    """Returns ``True`` if limiter is active and a redis DB is available."""
+    """Returns ``True`` if limiter is active and a valkey DB is available."""
     return _INSTALLED
 
 
@@ -229,15 +229,15 @@ def initialize(app: flask.Flask, settings):
     # (e.g. the self_info plugin uses the botdetection to get client IP)
 
     cfg = get_cfg()
-    redis_client = redisdb.client()
-    botdetection.init(cfg, redis_client)
+    valkey_client = valkeydb.client()
+    botdetection.init(cfg, valkey_client)
 
     if not (settings['server']['limiter'] or settings['server']['public_instance']):
         return
 
-    if not redis_client:
+    if not valkey_client:
         logger.error(
-            "The limiter requires Redis, please consult the documentation: "
+            "The limiter requires Valkey, please consult the documentation: "
             "https://docs.searxng.org/admin/searx.limiter.html"
         )
         if settings['server']['public_instance']:
diff --git a/searx/redisdb.py b/searx/redisdb.py
deleted file mode 100644
index bed0c347b..000000000
--- a/searx/redisdb.py
+++ /dev/null
@@ -1,69 +0,0 @@
-# SPDX-License-Identifier: AGPL-3.0-or-later
-"""Implementation of the redis client (redis-py_).
-
-.. _redis-py: https://github.com/redis/redis-py
-
-This implementation uses the :ref:`settings redis` setup from ``settings.yml``.
-A redis DB connect can be tested by::
-
-  >>> from searx import redisdb
-  >>> redisdb.initialize()
-  True
-  >>> db = redisdb.client()
-  >>> db.set("foo", "bar")
-  True
-  >>> db.get("foo")
-  b'bar'
-  >>>
-
-"""
-
-import os
-import pwd
-import logging
-import redis
-from searx import get_setting
-
-
-OLD_REDIS_URL_DEFAULT_URL = 'unix:///usr/local/searxng-redis/run/redis.sock?db=0'
-"""This was the default Redis URL in settings.yml."""
-
-_CLIENT = None
-logger = logging.getLogger(__name__)
-
-
-def client() -> redis.Redis:
-    return _CLIENT
-
-
-def initialize():
-    global _CLIENT  # pylint: disable=global-statement
-    redis_url = get_setting('redis.url')
-    if not redis_url:
-        return False
-    try:
-        # create a client, but no connection is done
-        _CLIENT = redis.Redis.from_url(redis_url)
-
-        # log the parameters as seen by the redis lib, without the password
-        kwargs = _CLIENT.get_connection_kwargs().copy()
-        kwargs.pop('password', None)
-        kwargs = ' '.join([f'{k}={v!r}' for k, v in kwargs.items()])
-        logger.info("connecting to Redis %s", kwargs)
-
-        # check the connection
-        _CLIENT.ping()
-
-        # no error: the redis connection is working
-        logger.info("connected to Redis")
-        return True
-    except redis.exceptions.RedisError as e:
-        _CLIENT = None
-        _pw = pwd.getpwuid(os.getuid())
-        logger.exception("[%s (%s)] can't connect redis DB ...", _pw.pw_name, _pw.pw_uid)
-        if redis_url == OLD_REDIS_URL_DEFAULT_URL and isinstance(e, redis.exceptions.ConnectionError):
-            logger.info(
-                "You can safely ignore the above Redis error if you don't use Redis. "
-                "You can remove this error by setting redis.url to false in your settings.yml."
-            )
-    return False
diff --git a/searx/search/checker/background.py b/searx/search/checker/background.py
index 7333e6ad0..1890c77d5 100644
--- a/searx/search/checker/background.py
+++ b/searx/search/checker/background.py
@@ -8,18 +8,18 @@ import os
 import signal
 from typing import Any, Dict, List, Literal, Optional, Tuple, TypedDict, Union
 
-import redis.exceptions
+import valkey.exceptions
 
 from searx import logger, settings, sxng_debug
-from searx.redisdb import client as get_redis_client
+from searx.valkeydb import client as get_valkey_client
 from searx.exceptions import SearxSettingsException
 from searx.search.processors import PROCESSORS
 from searx.search.checker import Checker
 from searx.search.checker.scheduler import scheduler_function
 
 
-REDIS_RESULT_KEY = 'SearXNG_checker_result'
-REDIS_LOCK_KEY = 'SearXNG_checker_lock'
+VALKEY_RESULT_KEY = 'SearXNG_checker_result'
+VALKEY_LOCK_KEY = 'SearXNG_checker_lock'
 
 
 CheckerResult = Union['CheckerOk', 'CheckerErr', 'CheckerOther']
@@ -77,23 +77,23 @@ def _get_interval(every: Any, error_msg: str) -> Tuple[int, int]:
 
 
 def get_result() -> CheckerResult:
-    client = get_redis_client()
+    client = get_valkey_client()
     if client is None:
-        # without Redis, the checker is disabled
+        # without Valkey, the checker is disabled
         return {'status': 'disabled'}
-    serialized_result: Optional[bytes] = client.get(REDIS_RESULT_KEY)
+    serialized_result: Optional[bytes] = client.get(VALKEY_RESULT_KEY)
     if serialized_result is None:
-        # the Redis key does not exist
+        # the Valkey key does not exist
         return {'status': 'unknown'}
     return json.loads(serialized_result)
 
 
 def _set_result(result: CheckerResult):
-    client = get_redis_client()
+    client = get_valkey_client()
     if client is None:
-        # without Redis, the function does nothing
+        # without Valkey, the function does nothing
         return
-    client.set(REDIS_RESULT_KEY, json.dumps(result))
+    client.set(VALKEY_RESULT_KEY, json.dumps(result))
 
 
 def _timestamp():
@@ -102,9 +102,9 @@ def _timestamp():
 
 def run():
     try:
-        # use a Redis lock to make sure there is no checker running at the same time
+        # use a Valkey lock to make sure there is no checker running at the same time
         # (this should not happen, this is a safety measure)
-        with get_redis_client().lock(REDIS_LOCK_KEY, blocking_timeout=60, timeout=3600):
+        with get_valkey_client().lock(VALKEY_LOCK_KEY, blocking_timeout=60, timeout=3600):
             logger.info('Starting checker')
             result: CheckerOk = {'status': 'ok', 'engines': {}, 'timestamp': _timestamp()}
             for name, processor in PROCESSORS.items():
@@ -118,7 +118,7 @@ def run():
 
             _set_result(result)
             logger.info('Check done')
-    except redis.exceptions.LockError:
+    except valkey.exceptions.LockError:
         _set_result({'status': 'error', 'timestamp': _timestamp()})
         logger.exception('Error while running the checker')
     except Exception:  # pylint: disable=broad-except
@@ -149,9 +149,9 @@ def initialize():
         logger.info('Checker scheduler is disabled')
         return
 
-    # make sure there is a Redis connection
-    if get_redis_client() is None:
-        logger.error('The checker requires Redis')
+    # make sure there is a Valkey connection
+    if get_valkey_client() is None:
+        logger.error('The checker requires Valkey')
         return
 
     # start the background scheduler
diff --git a/searx/search/checker/scheduler.lua b/searx/search/checker/scheduler.lua
index 0de9b404d..ec318ddd6 100644
--- a/searx/search/checker/scheduler.lua
+++ b/searx/search/checker/scheduler.lua
@@ -2,9 +2,9 @@
 --
 -- This script is not a string in scheduler.py, so editors can provide syntax highlighting.
 
--- The Redis KEY is defined here and not in Python on purpose:
+-- The Valkey KEY is defined here and not in Python on purpose:
 -- only this LUA script can read and update this key to avoid lock and concurrency issues.
-local redis_key = 'SearXNG_checker_next_call_ts'
+local valkey_key = 'SearXNG_checker_next_call_ts'
 
 local now = redis.call('TIME')[1]
 local start_after_from = ARGV[1]
@@ -12,14 +12,14 @@ local start_after_to = ARGV[2]
 local every_from = ARGV[3]
 local every_to = ARGV[4]
 
-local next_call_ts = redis.call('GET', redis_key)
+local next_call_ts = redis.call('GET', valkey_key)
 
 if (next_call_ts == false or next_call_ts == nil) then
-    -- the scheduler has never run on this Redis instance, so:
+    -- the scheduler has never run on this Valkey instance, so:
     -- 1/ the scheduler does not run now
     -- 2/ the next call is a random time between start_after_from and start_after_to
     local initial_delay = math.random(start_after_from, start_after_to)
-    redis.call('SET', redis_key, now + initial_delay)
+    redis.call('SET', valkey_key, now + initial_delay)
     return { false, initial_delay }
 end
 
@@ -31,6 +31,6 @@ if call_now then
     -- the checker runs now, define the timestamp of the next call:
     -- this is a random delay between every_from and every_to
     local periodic_delay = math.random(every_from, every_to)
-    next_call_ts = redis.call('INCRBY', redis_key, periodic_delay)
+    next_call_ts = redis.call('INCRBY', valkey_key, periodic_delay)
 end
 return { call_now, next_call_ts - now }
diff --git a/searx/search/checker/scheduler.py b/searx/search/checker/scheduler.py
index c0d3f799a..b093a9ab7 100644
--- a/searx/search/checker/scheduler.py
+++ b/searx/search/checker/scheduler.py
@@ -1,11 +1,11 @@
 # SPDX-License-Identifier: AGPL-3.0-or-later
 # pylint: disable=missing-module-docstring
-"""Lame scheduler which use Redis as a source of truth:
-* the Redis key SearXNG_checker_next_call_ts contains the next time the embedded checker should run.
-* to avoid lock, a unique Redis script reads and updates the Redis key SearXNG_checker_next_call_ts.
-* this Redis script returns a list of two elements:
+"""Lame scheduler which use Valkey as a source of truth:
+* the Valkey key SearXNG_checker_next_call_ts contains the next time the embedded checker should run.
+* to avoid lock, a unique Valkey script reads and updates the Valkey key SearXNG_checker_next_call_ts.
+* this Valkey script returns a list of two elements:
    * the first one is a boolean. If True, the embedded checker must run now in this worker.
-   * the second element is the delay in second to wait before the next call to the Redis script.
+   * the second element is the delay in second to wait before the next call to the Valkey script.
 
 This scheduler is not generic on purpose: if more feature are required, a dedicate scheduler must be used
 (= a better scheduler should not use the web workers)
@@ -16,8 +16,8 @@ import time
 from pathlib import Path
 from typing import Callable
 
-from searx.redisdb import client as get_redis_client
-from searx.redislib import lua_script_storage
+from searx.valkeydb import client as get_valkey_client
+from searx.valkeylib import lua_script_storage
 
 
 logger = logging.getLogger('searx.search.checker')
@@ -29,7 +29,7 @@ def scheduler_function(start_after_from: int, start_after_to: int, every_from: i
     """Run the checker periodically. The function never returns.
 
     Parameters:
-    * start_after_from and start_after_to: when to call "callback" for the first on the Redis instance
+    * start_after_from and start_after_to: when to call "callback" for the first on the Valkey instance
     * every_from and every_to: after the first call, how often to call "callback"
 
     There is no issue:
@@ -38,11 +38,11 @@ def scheduler_function(start_after_from: int, start_after_to: int, every_from: i
     """
     scheduler_now_script = SCHEDULER_LUA.open().read()
     while True:
-        # ask the Redis script what to do
+        # ask the Valkey script what to do
         # the script says
         # * if the checker must run now.
         # * how to long to way before calling the script again (it can be call earlier, but not later).
-        script = lua_script_storage(get_redis_client(), scheduler_now_script)
+        script = lua_script_storage(get_valkey_client(), scheduler_now_script)
         call_now, wait_time = script(args=[start_after_from, start_after_to, every_from, every_to])
 
         # does the worker run the checker now?
diff --git a/searx/settings.yml b/searx/settings.yml
index cb7504efe..fb85f0ff4 100644
--- a/searx/settings.yml
+++ b/searx/settings.yml
@@ -110,9 +110,10 @@ server:
     X-Robots-Tag: noindex, nofollow
     Referrer-Policy: no-referrer
 
-redis:
-  # URL to connect redis database. Is overwritten by ${SEARXNG_REDIS_URL}.
-  # https://docs.searxng.org/admin/settings/settings_redis.html#settings-redis
+valkey:
+  # URL to connect valkey database. Is overwritten by ${SEARXNG_VALKEY_URL}.
+  # https://docs.searxng.org/admin/settings/settings_valkey.html#settings-valkey
+  # url: valkey://localhost:6379/0
   url: false
 
 ui:
@@ -1809,10 +1810,10 @@ engines:
     shortcut: rt
     disabled: true
 
-  # Required dependency: redis
-  # - name: myredis
+  # Required dependency: valkey
+  # - name: myvalkey
   #   shortcut : rds
-  #   engine: redis_server
+  #   engine: valkey_server
   #   exact_match_only: false
   #   host: '127.0.0.1'
   #   port: 6379
diff --git a/searx/settings_defaults.py b/searx/settings_defaults.py
index 4cee7e345..7e785e4d2 100644
--- a/searx/settings_defaults.py
+++ b/searx/settings_defaults.py
@@ -185,9 +185,13 @@ SCHEMA = {
         'method': SettingsValue(('POST', 'GET'), 'POST', 'SEARXNG_METHOD'),
         'default_http_headers': SettingsValue(dict, {}),
     },
+    # redis is deprecated ..
     'redis': {
         'url': SettingsValue((None, False, str), False, 'SEARXNG_REDIS_URL'),
     },
+    'valkey': {
+        'url': SettingsValue((None, False, str), False, 'SEARXNG_VALKEY_URL'),
+    },
     'ui': {
         'static_path': SettingsDirectoryValue(str, os.path.join(searx_dir, 'static')),
         'static_use_hash': SettingsValue(bool, False, 'SEARXNG_STATIC_USE_HASH'),
diff --git a/searx/valkeydb.py b/searx/valkeydb.py
new file mode 100644
index 000000000..2817c6d0a
--- /dev/null
+++ b/searx/valkeydb.py
@@ -0,0 +1,65 @@
+# SPDX-License-Identifier: AGPL-3.0-or-later
+"""Implementation of the valkey client (valkey-py_).
+
+.. _valkey-py: https://github.com/valkey-io/valkey-py
+
+This implementation uses the :ref:`settings valkey` setup from ``settings.yml``.
+A valkey DB connect can be tested by::
+
+  >>> from searx import valkeydb
+  >>> valkeydb.initialize()
+  True
+  >>> db = valkeydb.client()
+  >>> db.set("foo", "bar")
+  True
+  >>> db.get("foo")
+  b'bar'
+  >>>
+
+"""
+
+import os
+import pwd
+import logging
+import warnings
+
+import valkey
+from searx import get_setting
+
+
+_CLIENT = None
+logger = logging.getLogger(__name__)
+
+
+def client() -> valkey.Valkey:
+    return _CLIENT
+
+
+def initialize():
+    global _CLIENT  # pylint: disable=global-statement
+    if get_setting('redis.url'):
+        warnings.warn("setting redis.url is deprecated, use valkey.url", DeprecationWarning)
+    valkey_url = get_setting('valkey.url') or get_setting('redis.url')
+    if not valkey_url:
+        return False
+    try:
+        # create a client, but no connection is done
+        _CLIENT = valkey.Valkey.from_url(valkey_url)
+
+        # log the parameters as seen by the valkey lib, without the password
+        kwargs = _CLIENT.get_connection_kwargs().copy()
+        kwargs.pop('password', None)
+        kwargs = ' '.join([f'{k}={v!r}' for k, v in kwargs.items()])
+        logger.info("connecting to Valkey %s", kwargs)
+
+        # check the connection
+        _CLIENT.ping()
+
+        # no error: the valkey connection is working
+        logger.info("connected to Valkey")
+        return True
+    except valkey.exceptions.ValkeyError:
+        _CLIENT = None
+        _pw = pwd.getpwuid(os.getuid())
+        logger.exception("[%s (%s)] can't connect valkey DB ...", _pw.pw_name, _pw.pw_uid)
+    return False
diff --git a/searx/redislib.py b/searx/valkeylib.py
index 5fa8f2dae..733988eb1 100644
--- a/searx/redislib.py
+++ b/searx/valkeylib.py
@@ -1,10 +1,10 @@
 # SPDX-License-Identifier: AGPL-3.0-or-later
-"""A collection of convenient functions and redis/lua scripts.
+"""A collection of convenient functions and valkey/lua scripts.
 
-This code was partial inspired by the `Bullet-Proofing Lua Scripts in RedisPy`_
+This code was partial inspired by the `Bullet-Proofing Lua Scripts in ValkeyPy`_
 article.
 
-.. _Bullet-Proofing Lua Scripts in RedisPy:
+.. _Bullet-Proofing Lua Scripts in ValkeyPy:
    https://redis.com/blog/bullet-proofing-lua-scripts-in-redispy/
 
 """
@@ -19,8 +19,8 @@ LUA_SCRIPT_STORAGE = {}
 
 
 def lua_script_storage(client, script):
-    """Returns a redis :py:obj:`Script
-    <redis.commands.core.CoreCommands.register_script>` instance.
+    """Returns a valkey :py:obj:`Script
+    <valkey.commands.core.CoreCommands.register_script>` instance.
 
     Due to performance reason the ``Script`` object is instantiated only once
     for a client (``client.register_script(..)``) and is cached in
@@ -28,7 +28,7 @@ def lua_script_storage(client, script):
 
     """
 
-    # redis connection can be closed, lets use the id() of the redis connector
+    # valkey connection can be closed, lets use the id() of the valkey connector
     # as key in the script-storage:
     client_id = id(client)
 
@@ -64,8 +64,8 @@ def purge_by_prefix(client, prefix: str = "SearXNG_"):
     :param prefix: prefix of the key to delete (default: ``SearXNG_``)
     :type name: str
 
-    .. _EXPIRE: https://redis.io/commands/expire/
-    .. _DEL: https://redis.io/commands/del/
+    .. _EXPIRE: https://valkey.io/commands/expire/
+    .. _DEL: https://valkey.io/commands/del/
 
     """
     script = lua_script_storage(client, PURGE_BY_PREFIX)
@@ -76,7 +76,7 @@ def secret_hash(name: str):
     """Creates a hash of the ``name``.
 
     Combines argument ``name`` with the ``secret_key`` from :ref:`settings
-    server`.  This function can be used to get a more anonymized name of a Redis
+    server`.  This function can be used to get a more anonymized name of a Valkey
     KEY.
 
     :param name: the name to create a secret hash for
@@ -112,12 +112,12 @@ return c
 def incr_counter(client, name: str, limit: int = 0, expire: int = 0):
     """Increment a counter and return the new value.
 
-    If counter with redis key ``SearXNG_counter_<name>`` does not exists it is
+    If counter with valkey key ``SearXNG_counter_<name>`` does not exists it is
     created with initial value 1 returned.  The replacement ``<name>`` is a
     *secret hash* of the value from argument ``name`` (see
     :py:func:`secret_hash`).
 
-    The implementation of the redis counter is the lua script from string
+    The implementation of the valkey counter is the lua script from string
     :py:obj:`INCR_COUNTER`.
 
     :param name: name of the counter
@@ -133,8 +133,8 @@ def incr_counter(client, name: str, limit: int = 0, expire: int = 0):
     :return: value of the incremented counter
     :type return: int
 
-    .. _EXPIRE: https://redis.io/commands/expire/
-    .. _INCR: https://redis.io/commands/incr/
+    .. _EXPIRE: https://valkey.io/commands/expire/
+    .. _INCR: https://valkey.io/commands/incr/
 
     A simple demo of a counter with expire time and limit::
 
@@ -157,7 +157,7 @@ def incr_counter(client, name: str, limit: int = 0, expire: int = 0):
 
 
 def drop_counter(client, name):
-    """Drop counter with redis key ``SearXNG_counter_<name>``
+    """Drop counter with valkey key ``SearXNG_counter_<name>``
 
     The replacement ``<name>`` is a *secret hash* of the value from argument
     ``name`` (see :py:func:`incr_counter` and :py:func:`incr_sliding_window`).
@@ -182,7 +182,7 @@ return result
 def incr_sliding_window(client, name: str, duration: int):
     """Increment a sliding-window counter and return the new value.
 
-    If counter with redis key ``SearXNG_counter_<name>`` does not exists it is
+    If counter with valkey key ``SearXNG_counter_<name>`` does not exists it is
     created with initial value 1 returned.  The replacement ``<name>`` is a
     *secret hash* of the value from argument ``name`` (see
     :py:func:`secret_hash`).
@@ -196,27 +196,27 @@ def incr_sliding_window(client, name: str, duration: int):
     :return: value of the incremented counter
     :type return: int
 
-    The implementation of the redis counter is the lua script from string
-    :py:obj:`INCR_SLIDING_WINDOW`.  The lua script uses `sorted sets in Redis`_
-    to implement a sliding window for the redis key ``SearXNG_counter_<name>``
+    The implementation of the valkey counter is the lua script from string
+    :py:obj:`INCR_SLIDING_WINDOW`.  The lua script uses `sorted sets in Valkey`_
+    to implement a sliding window for the valkey key ``SearXNG_counter_<name>``
     (ZADD_).  The current TIME_ is used to score the items in the sorted set and
     the time window is moved by removing items with a score lower current time
     minus *duration* time (ZREMRANGEBYSCORE_).
 
     The EXPIRE_ time (the duration of the sliding window) is refreshed on each
     call (increment) and if there is no call in this duration, the sorted
-    set expires from the redis DB.
+    set expires from the valkey DB.
 
     The return value is the amount of items in the sorted set (ZCOUNT_), what
     means the number of calls in the sliding window.
 
-    .. _Sorted sets in Redis:
-       https://redis.com/ebook/part-1-getting-started/chapter-1-getting-to-know-redis/1-2-what-redis-data-structures-look-like/1-2-5-sorted-sets-in-redis/
-    .. _TIME: https://redis.io/commands/time/
-    .. _ZADD: https://redis.io/commands/zadd/
-    .. _EXPIRE: https://redis.io/commands/expire/
-    .. _ZREMRANGEBYSCORE: https://redis.io/commands/zremrangebyscore/
-    .. _ZCOUNT: https://redis.io/commands/zcount/
+    .. _Sorted sets in Valkey:
+       https://valkey.com/ebook/part-1-getting-started/chapter-1-getting-to-know-valkey/1-2-what-valkey-data-structures-look-like/1-2-5-sorted-sets-in-valkey/
+    .. _TIME: https://valkey.io/commands/time/
+    .. _ZADD: https://valkey.io/commands/zadd/
+    .. _EXPIRE: https://valkey.io/commands/expire/
+    .. _ZREMRANGEBYSCORE: https://valkey.io/commands/zremrangebyscore/
+    .. _ZCOUNT: https://valkey.io/commands/zcount/
 
     A simple demo of the sliding window::
 
diff --git a/searx/webapp.py b/searx/webapp.py
index 868d95e3e..15f79f151 100755
--- a/searx/webapp.py
+++ b/searx/webapp.py
@@ -118,7 +118,7 @@ from searx.locales import (
 from searx.autocomplete import search_autocomplete, backends as autocomplete_backends
 from searx import favicons
 
-from searx.redisdb import initialize as redis_initialize
+from searx.valkeydb import initialize as valkey_initialize
 from searx.sxng_locales import sxng_locales
 import searx.search
 from searx.network import stream as http_stream, set_context_network_name
@@ -1397,7 +1397,7 @@ def init():
         return
 
     locales_initialize()
-    redis_initialize()
+    valkey_initialize()
     searx.plugins.initialize(app)
 
     metrics: bool = get_setting("general.enable_metrics")  # type: ignore