oncall-engine/engine/common/cache.py
Joey Orlando 49d20f1a7e
bump uwsgi to 2.0.26 + Python to 3.12.3 (#4495)
# What this PR does

- bumps `uwsgi` to latest version (`2.0.26`), which unblocks us from
bumping Python to 3.12
- bumps Python to 3.12.3
- refactor the Snyk GitHub Actions workflow to use the composable
actions for installed frontend and backend dependencies
- fixes several `AttributeError`s in our tests that went from a warning
to an error in Python 3.12 (see
https://github.com/python/cpython/issues/100690)

# Which issue(s) this PR closes

Closes #4358
Closes https://github.com/grafana/oncall/issues/4387
2024-06-10 15:33:37 -04:00

41 lines
1.9 KiB
Python

import typing
from django.conf import settings
_RT = typing.TypeVar("_RT", str, typing.List[str], typing.Dict[str, typing.Any])
def ensure_cache_key_allocates_to_the_same_hash_slot(cache_keys: _RT, pattern_to_wrap_in_brackets: str) -> _RT:
"""
This method will ensure that when using Redis Cluster, multiple cache keys will be allocated to the same hash slot.
This ensures that multi-key operations (ex `cache.get_many` and `cache.set_many`) will work without raising this
exception:
```
File "/usr/local/lib/python3.12/site-packages/redis/cluster.py", line 1006, in determine_slot
raise RedisClusterException(
redis.exceptions.RedisClusterException: MGET - all keys must map to the same key slot
```
From the Redis Cluster [docs](https://redis.io/docs/reference/cluster-spec/#hash-tags):
There is an exception for the computation of the hash slot that is used in order to implement hash tags.
Hash tags are a way to ensure that multiple keys are allocated in the same hash slot.
This is used in order to implement multi-key operations in Redis Cluster.
To implement hash tags, the hash slot for a key is computed in a slightly different way in certain conditions.
If the key contains a "{...}" pattern only the substring between { and } is hashed in order to obtain the hash slot.
However since it is possible that there are multiple occurrences of { or } the algorithm is well specified by the
following rules:
"""
if not settings.USE_REDIS_CLUSTER:
return cache_keys
def _replace_key(key: str) -> str:
return key.replace(pattern_to_wrap_in_brackets, f"{{{pattern_to_wrap_in_brackets}}}")
if isinstance(cache_keys, str):
return _replace_key(cache_keys)
elif isinstance(cache_keys, dict):
return {_replace_key(key): value for key, value in cache_keys.items()}
return [_replace_key(key) for key in cache_keys]