searxng/searx/redisdb.py
Markus Heiser 1184caa0fd [mod] RangeTable - fast lookup of a integer (IP) in a range table
This patch implements a table of ranges.  A *range* is a series of integers,
e.g. 0-10 with start value 0 and end value 10.

Start and end values are stored in a two-column table, the RangeTable.  This
table is stored in Redis in a sorted list and a ZRANGEBYSCORE query can be used
to determine if a particular integer is contained in one of the ranges in the
table.

The ZRANGEBYSCORE query scales with O(log(N)). To make it more clear: a query in
a table with 1 million ranges takes just twice as long as the query in a table
with 1000 ranges.

A RangeTable is excellent for IP ranges and ultra-fast queries to see if an
IP (which is nothing but an integer) is contained in one of the ranges of the
table.

Typical applications are e.g. large IP block lists or network ranges.

Signed-off-by: Markus Heiser <markus.heiser@darmarit.de>
2023-10-20 14:55:30 +02:00

71 lines
2.1 KiB
Python

# SPDX-License-Identifier: AGPL-3.0-or-later
# lint: pylint
"""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: redis.Redis = None # type: ignore
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) # type: ignore
# 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 # type: ignore
_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