11"""Split evaluator module."""
2- import threading
3- from collections import defaultdict , namedtuple
42from enum import Enum
53
6- from splitio .models .impressions import Impression
7- from splitio .engine .hashfns import murmur_128
8- from splitio .engine .cache .lru import SimpleLruCache
94from splitio .client .listener import ImpressionListenerException
10- from splitio import util
11-
12-
13- _TIME_INTERVAL_MS = 3600 * 1000 # one hour
14- _IMPRESSION_OBSERVER_CACHE_SIZE = 500000
15-
165
176class ImpressionsMode (Enum ):
187 """Impressions tracking mode."""
198
209 OPTIMIZED = "OPTIMIZED"
2110 DEBUG = "DEBUG"
2211
23-
24- def truncate_time (timestamp_ms ):
25- """
26- Truncate a timestamp in milliseconds to have hour granularity.
27-
28- :param timestamp_ms: timestamp generated in the impression.
29- :type timestamp_ms: int
30-
31- :returns: a timestamp with hour, min, seconds, and ms set to 0.
32- :rtype: int
33- """
34- return timestamp_ms - (timestamp_ms % _TIME_INTERVAL_MS )
35-
36-
37- class Hasher (object ): # pylint:disable=too-few-public-methods
38- """Impression hasher."""
39-
40- _PATTERN = "%s:%s:%s:%s:%d"
41-
42- def __init__ (self , hash_fn = murmur_128 , seed = 0 ):
43- """
44- Class constructor.
45-
46- :param hash_fn: Hash function to apply (str, int) -> int
47- :type hash_fn: callable
48-
49- :param seed: seed to be provided when hashing
50- :type seed: int
51- """
52- self ._hash_fn = hash_fn
53- self ._seed = seed
54-
55- def _stringify (self , impression ):
56- """
57- Stringify an impression.
58-
59- :param impression: Impression to stringify using _PATTERN
60- :type impression: splitio.models.impressions.Impression
61-
62- :returns: a string representation of the impression
63- :rtype: str
64- """
65- return self ._PATTERN % (impression .matching_key if impression .matching_key else 'UNKNOWN' ,
66- impression .feature_name if impression .feature_name else 'UNKNOWN' ,
67- impression .treatment if impression .treatment else 'UNKNOWN' ,
68- impression .label if impression .label else 'UNKNOWN' ,
69- impression .change_number if impression .change_number else 0 )
70-
71- def process (self , impression ):
72- """
73- Hash an impression.
74-
75- :param impression: Impression to hash.
76- :type impression: splitio.models.impressions.Impression
77-
78- :returns: a hash of the supplied impression's relevant fields.
79- :rtype: int
80- """
81- return self ._hash_fn (self ._stringify (impression ), self ._seed )
82-
83-
84- class Observer (object ): # pylint:disable=too-few-public-methods
85- """Observe impression and add a previous time if applicable."""
86-
87- def __init__ (self , size ):
88- """Class constructor."""
89- self ._hasher = Hasher ()
90- self ._cache = SimpleLruCache (size )
91-
92- def test_and_set (self , impression ):
93- """
94- Examine an impression to determine and set it's previous time accordingly.
95-
96- :param impression: Impression to track
97- :type impression: splitio.models.impressions.Impression
98-
99- :returns: Impression with populated previous time
100- :rtype: splitio.models.impressions.Impression
101- """
102- previous_time = self ._cache .test_and_set (self ._hasher .process (impression ), impression .time )
103- return Impression (impression .matching_key ,
104- impression .feature_name ,
105- impression .treatment ,
106- impression .label ,
107- impression .change_number ,
108- impression .bucketing_key ,
109- impression .time ,
110- previous_time )
111-
112-
113- class Counter (object ):
114- """Class that counts impressions per timeframe."""
115-
116- CounterKey = namedtuple ('Count' , ['feature' , 'timeframe' ])
117- CountPerFeature = namedtuple ('CountPerFeature' , ['feature' , 'timeframe' , 'count' ])
118-
119- def __init__ (self ):
120- """Class constructor."""
121- self ._data = defaultdict (lambda : 0 )
122- self ._lock = threading .Lock ()
123-
124- def track (self , impressions , inc = 1 ):
125- """
126- Register N new impressions for a feature in a specific timeframe.
127-
128- :param impressions: generated impressions
129- :type impressions: list[splitio.models.impressions.Impression]
130-
131- :param inc: amount to increment (defaults to 1)
132- :type inc: int
133- """
134- keys = [Counter .CounterKey (i .feature_name , truncate_time (i .time )) for i in impressions ]
135- with self ._lock :
136- for key in keys :
137- self ._data [key ] += inc
138-
139- def pop_all (self ):
140- """
141- Clear and return all the counters currently stored.
142-
143- :returns: List of count per feature/timeframe objects
144- :rtype: list[ImpressionCounter.CountPerFeature]
145- """
146- with self ._lock :
147- old = self ._data
148- self ._data = defaultdict (lambda : 0 )
149-
150- return [Counter .CountPerFeature (k .feature , k .timeframe , v )
151- for (k , v ) in old .items ()]
152-
153-
15412class Manager (object ): # pylint:disable=too-few-public-methods
15513 """Impression manager."""
15614
157- def __init__ (self , mode = ImpressionsMode . OPTIMIZED , standalone = True , listener = None ):
15+ def __init__ (self , listener = None , strategy = None ):
15816 """
15917 Construct a manger to track and forward impressions to the queue.
16018
@@ -167,8 +25,8 @@ def __init__(self, mode=ImpressionsMode.OPTIMIZED, standalone=True, listener=Non
16725 :param listener: Optional impressions listener that will capture all seen impressions.
16826 :type listener: splitio.client.listener.ImpressionListenerWrapper
16927 """
170- self . _observer = Observer ( _IMPRESSION_OBSERVER_CACHE_SIZE ) if standalone else None
171- self ._counter = Counter () if standalone and mode == ImpressionsMode . OPTIMIZED else None
28+
29+ self ._strategy = strategy
17230 self ._listener = listener
17331
17432 def process_impressions (self , impressions ):
@@ -180,26 +38,9 @@ def process_impressions(self, impressions):
18038 :param impressions: List of impression objects with attributes
18139 :type impressions: list[tuple[splitio.models.impression.Impression, dict]]
18240 """
183- imps = [(self ._observer .test_and_set (imp ), attrs ) for imp , attrs in impressions ] \
184- if self ._observer else impressions
185-
186- if self ._counter :
187- self ._counter .track ([imp for imp , _ in imps ])
188-
189- self ._send_impressions_to_listener (imps )
190-
191- this_hour = truncate_time (util .utctime_ms ())
192- return [imp for imp , _ in imps ] if self ._counter is None \
193- else [i for i , _ in imps if i .previous_time is None or i .previous_time < this_hour ]
194-
195- def get_counts (self ):
196- """
197- Return counts of impressions per features.
198-
199- :returns: A list of counter objects.
200- :rtype: list[Counter.CountPerFeature]
201- """
202- return self ._counter .pop_all () if self ._counter is not None else []
41+ for_log , for_listener = self ._strategy .process_impressions (impressions )
42+ self ._send_impressions_to_listener (for_listener )
43+ return for_log
20344
20445 def _send_impressions_to_listener (self , impressions ):
20546 """
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