You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
118 lines
3.2 KiB
118 lines
3.2 KiB
from __future__ import absolute_import
|
|
|
|
from kafka.vendor import six
|
|
|
|
from .base import Partitioner
|
|
|
|
|
|
class Murmur2Partitioner(Partitioner):
|
|
"""
|
|
Implements a partitioner which selects the target partition based on
|
|
the hash of the key. Attempts to apply the same hashing
|
|
function as mainline java client.
|
|
"""
|
|
def __call__(self, key, partitions=None, available=None):
|
|
if available:
|
|
return self.partition(key, available)
|
|
return self.partition(key, partitions)
|
|
|
|
def partition(self, key, partitions=None):
|
|
if not partitions:
|
|
partitions = self.partitions
|
|
|
|
# https://github.com/apache/kafka/blob/0.8.2/clients/src/main/java/org/apache/kafka/clients/producer/internals/Partitioner.java#L69
|
|
idx = (murmur2(key) & 0x7fffffff) % len(partitions)
|
|
|
|
return partitions[idx]
|
|
|
|
|
|
class LegacyPartitioner(object):
|
|
"""DEPRECATED -- See Issue 374
|
|
|
|
Implements a partitioner which selects the target partition based on
|
|
the hash of the key
|
|
"""
|
|
def __init__(self, partitions):
|
|
self.partitions = partitions
|
|
|
|
def partition(self, key, partitions=None):
|
|
if not partitions:
|
|
partitions = self.partitions
|
|
size = len(partitions)
|
|
idx = hash(key) % size
|
|
|
|
return partitions[idx]
|
|
|
|
|
|
# Default will change to Murmur2 in 0.10 release
|
|
HashedPartitioner = LegacyPartitioner
|
|
|
|
|
|
# https://github.com/apache/kafka/blob/0.8.2/clients/src/main/java/org/apache/kafka/common/utils/Utils.java#L244
|
|
def murmur2(data):
|
|
"""Pure-python Murmur2 implementation.
|
|
|
|
Based on java client, see org.apache.kafka.common.utils.Utils.murmur2
|
|
|
|
Args:
|
|
data (bytes): opaque bytes
|
|
|
|
Returns: MurmurHash2 of data
|
|
"""
|
|
# Python2 bytes is really a str, causing the bitwise operations below to fail
|
|
# so convert to bytearray.
|
|
if six.PY2:
|
|
data = bytearray(bytes(data))
|
|
|
|
length = len(data)
|
|
seed = 0x9747b28c
|
|
# 'm' and 'r' are mixing constants generated offline.
|
|
# They're not really 'magic', they just happen to work well.
|
|
m = 0x5bd1e995
|
|
r = 24
|
|
|
|
# Initialize the hash to a random value
|
|
h = seed ^ length
|
|
length4 = length // 4
|
|
|
|
for i in range(length4):
|
|
i4 = i * 4
|
|
k = ((data[i4 + 0] & 0xff) +
|
|
((data[i4 + 1] & 0xff) << 8) +
|
|
((data[i4 + 2] & 0xff) << 16) +
|
|
((data[i4 + 3] & 0xff) << 24))
|
|
k &= 0xffffffff
|
|
k *= m
|
|
k &= 0xffffffff
|
|
k ^= (k % 0x100000000) >> r # k ^= k >>> r
|
|
k &= 0xffffffff
|
|
k *= m
|
|
k &= 0xffffffff
|
|
|
|
h *= m
|
|
h &= 0xffffffff
|
|
h ^= k
|
|
h &= 0xffffffff
|
|
|
|
# Handle the last few bytes of the input array
|
|
extra_bytes = length % 4
|
|
if extra_bytes >= 3:
|
|
h ^= (data[(length & ~3) + 2] & 0xff) << 16
|
|
h &= 0xffffffff
|
|
if extra_bytes >= 2:
|
|
h ^= (data[(length & ~3) + 1] & 0xff) << 8
|
|
h &= 0xffffffff
|
|
if extra_bytes >= 1:
|
|
h ^= (data[length & ~3] & 0xff)
|
|
h &= 0xffffffff
|
|
h *= m
|
|
h &= 0xffffffff
|
|
|
|
h ^= (h % 0x100000000) >> 13 # h >>> 13;
|
|
h &= 0xffffffff
|
|
h *= m
|
|
h &= 0xffffffff
|
|
h ^= (h % 0x100000000) >> 15 # h >>> 15;
|
|
h &= 0xffffffff
|
|
|
|
return h
|