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from django.conf import settings
from django.core import checks
SUPPORTED_CACHE_BACKENDS = [
'django.core.cache.backends.memcached.PyMemcacheCache',
'django.core.cache.backends.memcached.PyLibMCCache',
'django_redis.cache.RedisCache',
]
CACHE_FAKE = 'is not a real cache'
CACHE_NOT_SHARED = 'is not a shared cache'
CACHE_NOT_ATOMIC = 'does not support atomic increment'
KNOWN_BROKEN_CACHE_BACKENDS = {
'django.core.cache.backends.dummy.DummyCache': CACHE_FAKE,
'django.core.cache.backends.locmem.LocMemCache': CACHE_NOT_SHARED,
'django.core.cache.backends.filebased.FileBasedCache': CACHE_NOT_ATOMIC,
'django.core.cache.backends.db.DatabaseCache': CACHE_NOT_ATOMIC,
}
@checks.register(checks.Tags.caches, 'django_ratelimit')
def check_caches(app_configs, **kwargs):
errors = []
cache_name = getattr(settings, 'RATELIMIT_USE_CACHE', 'default')
caches = getattr(settings, 'CACHES', None)
if caches is None:
errors.append(
checks.Error(
'CACHES is not defined, django_ratelimit will not work',
hint='Configure a default cache using memcached or redis.',
id='django_ratelimit.E001',
)
)
return errors
if cache_name not in caches:
errors.append(
checks.Error(
f'RATELIMIT_USE_CACHE value "{cache_name}"" does not '
f'appear in CACHES dictionary',
hint='RATELIMIT_USE_CACHE must be set to a valid cache',
id='django_ratelimit.E002',
)
)
return errors
cache_config = caches[cache_name]
backend = cache_config['BACKEND']
reason = KNOWN_BROKEN_CACHE_BACKENDS.get(backend, None)
if reason is not None:
errors.append(
checks.Error(
f'cache backend {backend} {reason}',
hint='Use a supported cache backend',
id='django_ratelimit.E003',
)
)
if backend not in SUPPORTED_CACHE_BACKENDS:
errors.append(
checks.Warning(
f'cache backend {backend} is not officially supported',
id='django_ratelimit.W001',
)
)
return errors
|
