zulip/zerver/lib/redis_utils.py

97 lines
2.7 KiB
Python

import os
import re
import secrets
from collections.abc import Mapping
from typing import Any
import orjson
import redis
from django.conf import settings
# Redis accepts keys up to 512MB in size, but there's no reason for us to use such size,
# so we want to stay limited to 1024 characters.
MAX_KEY_LENGTH = 1024
class ZulipRedisError(Exception):
pass
class ZulipRedisKeyTooLongError(ZulipRedisError):
pass
class ZulipRedisKeyOfWrongFormatError(ZulipRedisError):
pass
def get_redis_client() -> "redis.StrictRedis[bytes]":
return redis.StrictRedis(
host=settings.REDIS_HOST,
port=settings.REDIS_PORT,
password=settings.REDIS_PASSWORD,
db=0,
decode_responses=False,
)
def put_dict_in_redis(
redis_client: "redis.StrictRedis[bytes]",
key_format: str,
data_to_store: Mapping[str, Any],
expiration_seconds: int,
token_length: int = 64,
token: str | None = None,
) -> str:
key_length = len(key_format) - len("{token}") + token_length
if key_length > MAX_KEY_LENGTH:
raise ZulipRedisKeyTooLongError(
f"Requested key too long in put_dict_in_redis. Key format: {key_format}, token length: {token_length}",
)
if token is None:
token = secrets.token_hex(token_length // 2)
key = key_format.format(token=token)
with redis_client.pipeline() as pipeline:
pipeline.set(key, orjson.dumps(data_to_store))
pipeline.expire(key, expiration_seconds)
pipeline.execute()
return key
def get_dict_from_redis(
redis_client: "redis.StrictRedis[bytes]",
key_format: str,
key: str,
) -> dict[str, Any] | None:
# This function requires inputting the intended key_format to validate
# that the key fits it, as an additionally security measure. This protects
# against bugs where a caller requests a key based on user input and doesn't
# validate it - which could potentially allow users to poke around arbitrary Redis keys.
if len(key) > MAX_KEY_LENGTH:
raise ZulipRedisKeyTooLongError(
f"Requested key too long in get_dict_from_redis: {key}",
)
validate_key_fits_format(key, key_format)
data = redis_client.get(key)
if data is None:
return None
return orjson.loads(data)
def validate_key_fits_format(key: str, key_format: str) -> None:
assert "{token}" in key_format
regex = key_format.format(token=r"[a-zA-Z0-9]+")
if not re.fullmatch(regex, key):
raise ZulipRedisKeyOfWrongFormatError(f"{key} does not match format {key_format}")
REDIS_KEY_PREFIX = ""
def bounce_redis_key_prefix_for_testing(test_name: str) -> None:
global REDIS_KEY_PREFIX
REDIS_KEY_PREFIX = test_name + ":" + str(os.getpid()) + ":"