def kv_put(key, value, overwrite=False):
"""PUTs a key-value pair for `key` and `value`
`overwrite` == True : overwrites if `key` already exists
`overwrite` == False : raises Exception if `key` already exists
"""
KV = get_kv_storage_model()
kv_obj = None
if KV:
if overwrite:
# attempt to retrieve an existing
kv_obj = _get_kv_obj(key)
if kv_obj:
# overwrite the value
kv_obj.value = value
kv_obj.save()
if not kv_obj:
# overwrite == False or does not already exist
kv_obj = KV.objects.create(
key=key,
value=value
)
if kv_obj:
# update the cache if value was successfully written
c = KVStorageCache(prekey=key)
c.cache_store(value)
return kv_obj
def kv_delete(key):
"""DELETEs `key` from key-value storage
"""
c = KVStorageCache(prekey=key)
c.invalidate_cache()
kv_obj = _get_kv_obj(key)
if kv_obj:
kv_obj.delete()
def kv_get(key, cache_only=False):
"""GETs the value of `key` from key-value storage
`cache_only` == True : skips lookup in db, returns the cached value or None
"""
c = KVStorageCache(prekey=key)
value = c.get()
if value is None and not cache_only:
kv_obj = _get_kv_obj(key)
if kv_obj:
value = kv_obj.value
c.cache_store(value)
return value
def _get_kv_cache(key, namespace=None):
from htk.apps.kv_storage.cachekeys import KVStorageCache
if namespace is None:
prekey = key
else:
prekey = (
namespace,
key,
)
c = KVStorageCache(prekey=prekey)
return c