-
Notifications
You must be signed in to change notification settings - Fork 36
/
cache_engine.py
84 lines (64 loc) · 1.96 KB
/
cache_engine.py
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
#!/usr/bin/env python
# -*- coding: utf-8 -*-
#-----------------------
# Name: cache_engine.py
# Python Library
# Author: Raymond Wagner
# Purpose: Base cache engine class for collecting registered engines
#-----------------------
import time
from weakref import ref
class Engines(object):
"""
Static collector for engines to register against.
"""
def __init__(self):
self._engines = {}
def register(self, engine):
self._engines[engine.__name__] = engine
self._engines[engine.name] = engine
def __getitem__(self, key):
return self._engines[key]
def __contains__(self, key):
return self._engines.__contains__(key)
Engines = Engines()
class CacheEngineType(type):
"""
Cache Engine Metaclass that registers new engines against the cache
for named selection and use.
"""
def __init__(cls, name, bases, attrs):
super(CacheEngineType, cls).__init__(name, bases, attrs)
if name != 'CacheEngine':
# skip base class
Engines.register(cls)
class CacheEngine(object):
__metaclass__ = CacheEngineType
name = 'unspecified'
def __init__(self, parent):
self.parent = ref(parent)
def configure(self):
raise RuntimeError
def get(self, date):
raise RuntimeError
def put(self, key, value, lifetime):
raise RuntimeError
def expire(self, key):
raise RuntimeError
class CacheObject(object):
"""
Cache object class, containing one stored record.
"""
def __init__(self, key, data, lifetime=0, creation=None):
self.key = key
self.data = data
self.lifetime = lifetime
self.creation = creation if creation is not None else time.time()
def __len__(self):
return len(self.data)
@property
def expired(self):
return self.remaining == 0
@property
def remaining(self):
return max((self.creation + self.lifetime) - time.time(), 0)