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
84
85
86
87
88
89
|
#The MIT License (MIT)
#Copyright (c) 2014 Microsoft Corporation
#Permission is hereby granted, free of charge, to any person obtaining a copy
#of this software and associated documentation files (the "Software"), to deal
#in the Software without restriction, including without limitation the rights
#to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
#copies of the Software, and to permit persons to whom the Software is
#furnished to do so, subject to the following conditions:
#The above copyright notice and this permission notice shall be included in all
#copies or substantial portions of the Software.
#THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
#IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
#FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
#AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
#LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
#OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
#SOFTWARE.
"""Hash partition resolver implementation in the Azure Cosmos database service.
"""
import azure.cosmos.murmur_hash as murmur_hash
import azure.cosmos.consistent_hash_ring as consistent_hash_ring
class HashPartitionResolver(object):
"""HashPartitionResolver implements partitioning based on the value of a hash function, allowing you to evenly
distribute requests and data across a number of partitions.
"""
def __init__(self, partition_key_extractor, collection_links, default_number_of_virtual_nodes_per_collection = 128, hash_generator = None):
"""
:param lambda partition_key_extractor:
Returning the partition key from the document passed.
:param list collection_links:
The links of collections participating in partitioning.
:param int default_number_of_virtual_nodes_per_collection:
Number of virtual nodes per collection.
:param HashGenerator hash_generator:
The hash generator to be used for hashing algorithm.
"""
if partition_key_extractor is None:
raise ValueError("partition_key_extractor is None.")
if collection_links is None:
raise ValueError("collection_links is None.")
if default_number_of_virtual_nodes_per_collection <= 0:
raise ValueError("The number of virtual nodes per collection must greater than 0.")
self.partition_key_extractor = partition_key_extractor
self.collection_links = collection_links
if hash_generator is None:
hash_generator = murmur_hash._MurmurHash()
self.consistent_hash_ring = consistent_hash_ring._ConsistentHashRing(self.collection_links, default_number_of_virtual_nodes_per_collection, hash_generator)
def ResolveForCreate(self, document):
"""Resolves the collection for creating the document based on the partition key.
:param dict document:
The document to be created.
:return:
Collection Self link or Name based link which should handle the Create operation.
:rtype:
str
"""
if document is None:
raise ValueError("document is None.")
partition_key = self.partition_key_extractor(document)
return self.consistent_hash_ring.GetCollectionNode(partition_key)
def ResolveForRead(self, partition_key):
"""Resolves the collection for reading/querying the documents based on the partition key.
:param dict document:
The document to be read/queried.
:return:
Collection Self link(s) or Name based link(s) which should handle the Read operation.
:rtype:
list
"""
if partition_key is None:
return self.collection_links
else:
return [self.consistent_hash_ring.GetCollectionNode(partition_key)]
|
