searxng/searx/redisdb.py

# 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: 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