1
|
1 |
|
import logging |
2
|
|
|
|
3
|
1 |
|
log = logging.getLogger(__name__) |
4
|
|
|
|
5
|
1 |
|
IGNORED_EVENTS = [ |
6
|
|
|
'buffering' |
7
|
|
|
] |
8
|
|
|
|
9
|
|
|
|
10
|
1 |
|
class Engine(object): |
11
|
1 |
|
handlers = {} |
12
|
|
|
|
13
|
1 |
|
def __init__(self): |
14
|
1 |
|
self.handlers = self._construct_handlers(self.handlers) |
15
|
|
|
|
16
|
1 |
|
def process(self, obj, events): |
17
|
1 |
|
for key, payload in events: |
18
|
1 |
|
result = self.process_one(obj, key, payload) |
19
|
|
|
|
20
|
1 |
|
if not result: |
21
|
|
|
continue |
22
|
|
|
|
23
|
1 |
|
for item in result: |
24
|
1 |
|
yield item |
25
|
|
|
|
26
|
1 |
|
def process_one(self, obj, key, payload): |
27
|
|
|
# Ensure the event hasn't been ignored |
28
|
1 |
|
if key in IGNORED_EVENTS: |
29
|
|
|
log.debug('Ignored %r event', key) |
30
|
|
|
return |
31
|
|
|
|
32
|
|
|
# Try find handler for event |
33
|
1 |
|
handlers = self.handlers.get(key) |
34
|
|
|
|
35
|
1 |
|
if not handlers: |
36
|
|
|
raise Exception('No handlers found for %r event' % key) |
37
|
|
|
|
38
|
|
|
# Run handlers until we get a result |
39
|
1 |
|
result = None |
40
|
|
|
|
41
|
1 |
|
for h in handlers: |
42
|
1 |
|
if not h.is_valid_source(obj.state): |
43
|
1 |
|
log.info('Ignoring %r event for %r, invalid state transition', key, obj) |
44
|
1 |
|
continue |
45
|
|
|
|
46
|
1 |
|
result = h.process(obj, payload) |
47
|
1 |
|
break |
48
|
|
|
|
49
|
1 |
|
if result is None: |
50
|
1 |
|
return |
51
|
|
|
|
52
|
1 |
|
for item in result: |
53
|
1 |
|
if not item: |
54
|
|
|
continue |
55
|
|
|
|
56
|
1 |
|
state, data = item |
57
|
|
|
|
58
|
|
|
# Update current state/data |
59
|
1 |
|
self._set_attributes(obj, **data) |
60
|
|
|
|
61
|
1 |
|
if state is None: |
62
|
1 |
|
continue |
63
|
|
|
|
64
|
|
|
# New event |
65
|
1 |
|
obj.state = state |
66
|
|
|
|
67
|
|
|
# Save |
68
|
1 |
|
obj.save() |
69
|
|
|
|
70
|
1 |
|
yield state, data |
71
|
|
|
|
72
|
1 |
|
@staticmethod |
73
|
|
|
def find_handlers(handlers, func): |
74
|
|
|
result = [] |
75
|
|
|
|
76
|
|
|
for h in handlers: |
77
|
|
|
if not func(h): |
78
|
|
|
continue |
79
|
|
|
|
80
|
|
|
result.append(h) |
81
|
|
|
|
82
|
|
|
return result |
83
|
|
|
|
84
|
1 |
|
@classmethod |
85
|
|
|
def register(cls, kls): |
86
|
1 |
|
key = kls.__event__ |
87
|
|
|
|
88
|
1 |
|
if not key: |
89
|
|
|
raise Exception('Unable to register %r, missing "__key__" attribute' % kls) |
90
|
|
|
|
91
|
1 |
|
if key not in cls.handlers: |
92
|
1 |
|
cls.handlers[key] = [] |
93
|
|
|
|
94
|
1 |
|
cls.handlers[key].append(kls) |
95
|
|
|
|
96
|
1 |
|
@staticmethod |
97
|
|
|
def _construct_handlers(handlers): |
98
|
1 |
|
result = {} |
99
|
|
|
|
100
|
1 |
|
for key, classes in handlers.items(): |
101
|
1 |
|
objects = [] |
102
|
|
|
|
103
|
1 |
|
for kls in classes: |
104
|
1 |
|
objects.append(kls()) |
105
|
|
|
|
106
|
1 |
|
result[key] = objects |
107
|
|
|
|
108
|
1 |
|
return result |
109
|
|
|
|
110
|
1 |
|
@staticmethod |
111
|
|
|
def _set_attributes(obj, **kwargs): |
112
|
1 |
|
for key, value in kwargs.items(): |
113
|
1 |
|
if not hasattr(obj, key): |
114
|
|
|
raise Exception('Object %r is missing the attribute %r' % (obj, key)) |
115
|
|
|
|
116
|
1 |
|
setattr(obj, key, value) |
117
|
|
|
|
118
|
|
|
|
119
|
1 |
|
class SessionEngine(Engine): |
120
|
|
|
handlers = {} |
121
|
|
|
|