class CacheModule:
def __init__(self, name, max_size=128, from_remote=None):
'''
:param max_size: 最大容量
:param from_remote: 查询数据函数，返回值必须是一个dict
:param ttl: 有效时间，单位：秒
'''
self.local_cache = LRU(max_size=max_size)
self.from_remote = from_remote
self.empty = {}
self.name = name
def get_all(self, keys: list) -> dict:
result, missing_keys = {}, []
for key in keys:
val = self.local_cache.get(key)
if val is not None:
if val != self.empty:
result[key] = val
else:
missing_keys.append(key)
# 缓存未命中
if len(missing_keys) > 0:
missing_dict = self.reload(missing_keys)
result = {**result, **missing_dict}
return result
def remove(self, keys: list):
for key in keys:
self.local_cache.__delitem__(key)
def statistics(self):
hitRateAsString = '%.3f' % (
self.local_cache.hit_count /
(self.local_cache.hit_count + self.local_cache.miss_count))
return {
"name": self.name,
"hit_count": self.local_cache.hit_count,
"miss_count": self.local_cache.miss_count,
"size": len(self.local_cache.keys()),
"hitRateAsString": hitRateAsString + "%",
}
def reload(self, keys: list) -> dict:
d = {}
missing_vals = self.from_remote(keys)
# 不存在的值，设置为空
if missing_vals:
for key, val in missing_vals.items():
self.local_cache.setdefault(key, val)
d[key] = val
for missing_key in keys:
self.local_cache.setdefault(missing_key, self.empty)
return d
def test_lru():
lru = LRU(max_size=1)
lru['hi'] = 0
lru['bye'] = 1
assert len(lru) == 1
lru['bye']
assert lru.get('hi') is None
del lru['bye']
assert 'bye' not in lru
assert len(lru) == 0
assert not lru
class CacheModule:
def __init__(self, max_size: int, ttl_millis: int, from_remote):
'''
:param max_size: max_size of the cache,using LRU
:param ttl_millis: max live time for the objects
:param from_remote: function to load data if the key not exists
'''
self.cache = LRU(max_size=max_size)
self.ttl = ttl_millis
self.from_remote = from_remote
self._lock = RLock()
def multi_get(self, keys) -> dict:
result, missing = {}, []
now = int(round(time.time() * 1000))
for key in keys:
value: dict = self.cache.get(key)
# key未命中
if not value:
missing.append(key)
# key超时
elif now < value['max_time']:
missing.append(key)
# key存在且不是默认值
elif value['data']:
result[key] = value['data']
if len(missing) > 0:
loads_d: dict = self.from_remote(missing)
dft = {
'max_time': int(round(time.time() * 1000)) + self.ttl,
'data': {}
}
for key in missing:
loads_d.setdefault(key, dft)
self.multi_set(loads_d)
return result
def multi_set(self, data: dict):
with self._lock:
for k, v in data.items():
self.cache.setdefault(k, v)
def remove(self, keys):
with self._lock:
for key in keys:
self.cache.pop(key)
def test_lru_basic():
lru = LRU(max_size=1)
repr(lru) # sanity
lru['hi'] = 0
lru['bye'] = 1
assert len(lru) == 1
lru['bye']
assert lru.get('hi') is None
del lru['bye']
assert 'bye' not in lru
assert len(lru) == 0
assert not lru
try:
lru.pop('bye')
except KeyError:
pass
else:
assert False
default = object()
assert lru.pop('bye', default) is default
try:
lru.popitem()
except KeyError:
pass
else:
assert False
lru['another'] = 1
assert lru.popitem() == ('another', 1)
lru['yet_another'] = 2
assert lru.pop('yet_another') == 2
lru['yet_another'] = 3
assert lru.pop('yet_another', default) == 3
lru['yet_another'] = 4
lru.clear()
assert not lru
lru['yet_another'] = 5
second_lru = LRU(max_size=1)
assert lru.copy() == lru
second_lru['yet_another'] = 5
assert second_lru == lru
assert lru == second_lru
lru.update(LRU(max_size=2, values=[('a', 1), ('b', 2)]))
assert len(lru) == 1
assert 'yet_another' not in lru
lru.setdefault('x', 2)
assert dict(lru) == {'x': 2}
lru.setdefault('x', 3)
assert dict(lru) == {'x': 2}
assert lru != second_lru
assert second_lru != lru
def test_lru_basic():
lru = LRU(max_size=1)
repr(lru) # sanity
lru['hi'] = 0
lru['bye'] = 1
assert len(lru) == 1
lru['bye']
assert lru.get('hi') is None
del lru['bye']
assert 'bye' not in lru
assert len(lru) == 0
assert not lru
try:
lru.pop('bye')
except KeyError:
pass
else:
assert False
default = object()
assert lru.pop('bye', default) is default
try:
lru.popitem()
except KeyError:
pass
else:
assert False
lru['another'] = 1
assert lru.popitem() == ('another', 1)
lru['yet_another'] = 2
assert lru.pop('yet_another') == 2
lru['yet_another'] = 3
assert lru.pop('yet_another', default) == 3
lru['yet_another'] = 4
lru.clear()
assert not lru
lru['yet_another'] = 5
second_lru = LRU(max_size=1)
assert lru.copy() == lru
second_lru['yet_another'] = 5
assert second_lru == lru
assert lru == second_lru
lru.update(LRU(max_size=2, values=[('a', 1),
('b', 2)]))
assert len(lru) == 1
assert 'yet_another' not in lru
lru.setdefault('x', 2)
assert dict(lru) == {'x': 2}
lru.setdefault('x', 3)
assert dict(lru) == {'x': 2}
assert lru != second_lru
assert second_lru != lru
