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
|
import functools
import logging
log = logging.getLogger(__name__)
class Future(object):
def __init__(self):
self.is_done = False
self.value = None
self.exception = None
self._callbacks = []
self._errbacks = []
def succeeded(self):
return self.is_done and not bool(self.exception)
def failed(self):
return self.is_done and bool(self.exception)
def retriable(self):
try:
return self.exception.retriable
except AttributeError:
return False
def success(self, value):
assert not self.is_done, 'Future is already complete'
self.value = value
self.is_done = True
for f in self._callbacks:
try:
f(value)
except Exception:
log.exception('Error processing callback')
return self
def failure(self, e):
assert not self.is_done, 'Future is already complete'
self.exception = e if type(e) is not type else e()
assert isinstance(self.exception, BaseException), (
'future failed without an exception')
self.is_done = True
for f in self._errbacks:
try:
f(self.exception)
except Exception:
log.exception('Error processing errback')
return self
def add_callback(self, f, *args, **kwargs):
if args or kwargs:
f = functools.partial(f, *args, **kwargs)
if self.is_done and not self.exception:
f(self.value)
else:
self._callbacks.append(f)
return self
def add_errback(self, f, *args, **kwargs):
if args or kwargs:
f = functools.partial(f, *args, **kwargs)
if self.is_done and self.exception:
f(self.exception)
else:
self._errbacks.append(f)
return self
def add_both(self, f, *args, **kwargs):
self.add_callback(f, *args, **kwargs)
self.add_errback(f, *args, **kwargs)
return self
def chain(self, future):
self.add_callback(future.success)
self.add_errback(future.failure)
return self
|
