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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,165 @@ | ||
| from django.core.cache.backends.base import BaseCache | ||
| from django.core.cache import caches | ||
| from django.core.exceptions import ImproperlyConfigured | ||
|
|
||
| NUM_CACHE_RETRY = 3 | ||
| DEFAULT_L0_TIMEOUT = 300 | ||
| NONE_RESULT = "__None__" | ||
| l0_cache = caches["l0"] if "l0" in caches else None | ||
| primary_cache = caches["primary"] if "primary" in caches else None | ||
|
|
||
|
|
||
| class CacheHandler(BaseCache): | ||
| """ | ||
| Custom Django cache backend with support for L0 (short-term) and primary cache layers. | ||
| """ | ||
|
|
||
| def __init__(self, location, params): | ||
| """ | ||
| Initialize the cache backend with L0 and primary (default) cache. | ||
| """ | ||
| super().__init__(params) | ||
|
|
||
| def get(self, key, default=None): | ||
| """ | ||
| Retrieve a value from the cache with retry logic and L0 caching. | ||
| """ | ||
| if l0_cache: | ||
| result = l0_cache.get(key) | ||
| if result is not None: | ||
| return None if result == NONE_RESULT else result | ||
|
|
||
| for attempt in range(NUM_CACHE_RETRY): | ||
| try: | ||
| result = primary_cache.get(key) | ||
| if result is not None: | ||
| if l0_cache: | ||
| l0_cache.set( | ||
| key, | ||
| NONE_RESULT if result is None else result, | ||
| DEFAULT_L0_TIMEOUT, | ||
| ) # Cache in L0 | ||
| return None if result == NONE_RESULT else result | ||
| except Exception: | ||
| if attempt == NUM_CACHE_RETRY - 1: | ||
| raise | ||
| return default | ||
|
|
||
| def set(self, key, value, timeout=None): | ||
| """ | ||
| Set a value in the cache and optionally in the L0 cache. | ||
| """ | ||
| value_to_store = NONE_RESULT if value is None else value | ||
| if l0_cache: | ||
| l0_cache.set(key, value_to_store, DEFAULT_L0_TIMEOUT) | ||
| primary_cache.set(key, value_to_store, timeout) | ||
|
|
||
| def delete(self, key): | ||
| """ | ||
| Delete a value from both L0 and primary cache. | ||
| """ | ||
| if l0_cache: | ||
| l0_cache.delete(key) | ||
| primary_cache.delete(key) | ||
|
|
||
| def add(self, key, value, timeout=None): | ||
| """ | ||
| Add a value to the cache only if the key does not already exist. | ||
| """ | ||
| value_to_store = NONE_RESULT if value is None else value | ||
| if l0_cache and not l0_cache.get(key): | ||
| l0_cache.set(key, value_to_store, DEFAULT_L0_TIMEOUT) | ||
| primary_cache.add(key, value_to_store, timeout) | ||
|
|
||
| def get_many(self, keys): | ||
| """ | ||
| Retrieve multiple values from the cache. | ||
| """ | ||
| results = {} | ||
| if l0_cache: | ||
| l0_results = l0_cache.get_many(keys) | ||
| results.update( | ||
| { | ||
| key: (None if value == NONE_RESULT else value) | ||
| for key, value in l0_results.items() | ||
| } | ||
| ) | ||
| keys = [key for key in keys if key not in l0_results] | ||
|
|
||
| if not keys: | ||
| return results | ||
|
|
||
| for attempt in range(NUM_CACHE_RETRY): | ||
| try: | ||
| cache_results = primary_cache.get_many(keys) | ||
| if l0_cache: | ||
| for key, value in cache_results.items(): | ||
| l0_cache.set( | ||
| key, | ||
| NONE_RESULT if value is None else value, | ||
| DEFAULT_L0_TIMEOUT, | ||
| ) | ||
| results.update( | ||
| { | ||
| key: (None if value == NONE_RESULT else value) | ||
| for key, value in cache_results.items() | ||
| } | ||
| ) | ||
| return results | ||
| except Exception: | ||
| if attempt == NUM_CACHE_RETRY - 1: | ||
| raise | ||
| return results | ||
|
|
||
| def set_many(self, data, timeout=None): | ||
| """ | ||
| Set multiple values in the cache. | ||
| """ | ||
| data_to_store = { | ||
| key: (NONE_RESULT if value is None else value) | ||
| for key, value in data.items() | ||
| } | ||
| if l0_cache: | ||
| for key, value in data_to_store.items(): | ||
| l0_cache.set(key, value, DEFAULT_L0_TIMEOUT) | ||
| primary_cache.set_many(data_to_store, timeout) | ||
|
|
||
| def delete_many(self, keys): | ||
| """ | ||
| Delete multiple values from the cache. | ||
| """ | ||
| if l0_cache: | ||
| l0_cache.delete_many(keys) | ||
| primary_cache.delete_many(keys) | ||
|
|
||
| def clear(self): | ||
| """ | ||
| Clear both L0 and primary caches. | ||
| """ | ||
| if l0_cache: | ||
| l0_cache.clear() | ||
| primary_cache.clear() | ||
|
|
||
| def incr(self, key, delta=1): | ||
| """ | ||
| Increment a value in the cache. | ||
| """ | ||
| if l0_cache: | ||
| l0_value = l0_cache.get(key) | ||
| if l0_value and l0_value != NONE_RESULT: | ||
| updated_value = l0_value + delta | ||
| l0_cache.set(key, updated_value, DEFAULT_L0_TIMEOUT) | ||
| return updated_value | ||
| return primary_cache.incr(key, delta) | ||
|
|
||
| def decr(self, key, delta=1): | ||
| """ | ||
| Decrement a value in the cache. | ||
| """ | ||
| if l0_cache: | ||
| l0_value = l0_cache.get(key) | ||
| if l0_value and l0_value != NONE_RESULT: | ||
| updated_value = l0_value - delta | ||
| l0_cache.set(key, updated_value, DEFAULT_L0_TIMEOUT) | ||
| return updated_value | ||
| return primary_cache.decr(key, delta) |
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