searxng/searx/search/checker/scheduler.lua
Gaspard d'Hautefeuille f798ddd492
[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>
2025-07-09 07:55:37 +02:00

36 lines
1.5 KiB
Lua

-- SPDX-License-Identifier: AGPL-3.0-or-later
--
-- This script is not a string in scheduler.py, so editors can provide syntax highlighting.
-- 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 valkey_key = 'SearXNG_checker_next_call_ts'
local now = redis.call('TIME')[1]
local start_after_from = ARGV[1]
local start_after_to = ARGV[2]
local every_from = ARGV[3]
local every_to = ARGV[4]
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 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', valkey_key, now + initial_delay)
return { false, initial_delay }
end
-- next_call_ts is defined
-- --> if now is lower than next_call_ts then we don't run the embedded checker
-- --> if now is higher then we update next_call_ts and ask to run the embedded checker now.
local call_now = next_call_ts <= now
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', valkey_key, periodic_delay)
end
return { call_now, next_call_ts - now }