searxng/searx/search/checker/scheduler.py
Markus Heiser 86b4d2f2d0 [mod] activate pyright checks (in CI)
We have been using a static type checker (pyright) for a long time, but its
check was not yet a prerequisite for passing the quality gate.  It was checked
in the CI, but the error messages were only logged.

As is always the case in life, with checks that you have to do but which have no
consequences; you neglect them :-)

We didn't activate the checks back then because we (even today) have too much
monkey patching in our code (not only in the engines, httpx and others objects
are also affected).

We want to replace monkey patching with clear interfaces for a long time, the
basis for this is increased typing and we can only achieve this if we make type
checking an integral part of the quality gate.

  This PR activates the type check; in order to pass the check, a few typings
  were corrected in the code, but most type inconsistencies were deactivated via
  inline comments.

This was particularly necessary in places where the code uses properties that
stick to the objects (monkey patching).  The sticking of properties only happens
in a few places, but the access to these properties extends over the entire
code, which is why there are many `# type: ignore` markers in the code ... which
we will hopefully be able to remove again successively in the future.

Signed-off-by: Markus Heiser <markus.heiser@darmarit.de>
2024-04-27 18:31:52 +02:00

59 lines
2.5 KiB
Python

# 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:
* 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.
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)
"""
from typing import Callable
import logging
import time
from pathlib import Path
from searx.redisdb import client as get_redis_client
from searx.redislib import lua_script_storage
logger = logging.getLogger('searx.search.checker')
SCHEDULER_LUA = Path(__file__).parent / "scheduler.lua"
def scheduler_function(start_after_from: int, start_after_to: int, every_from: int, every_to: int, callback: Callable):
"""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
* every_from and every_to: after the first call, how often to call "callback"
There is no issue:
* to call this function is multiple workers
* to kill workers at any time as long there is one at least one worker
"""
scheduler_now_script = SCHEDULER_LUA.open().read()
while True:
# ask the Redis 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)
call_now, wait_time = script(args=[start_after_from, start_after_to, every_from, every_to])
# does the worker run the checker now?
if call_now:
# run the checker
try:
callback()
except Exception: # pylint: disable=broad-except
logger.exception("Error calling the embedded checker")
# only worker display the wait_time
logger.info("Next call to the checker in %s seconds", wait_time)
# wait until the next call
time.sleep(wait_time)