Hadoop Python 调用自定义so动态库

使用import需要在所有宿主机安装相应模块，但使用ctypes库可以调用

•  test.c

#include <stdio.h>

int add(int);
int out(); 
int buffer[100];
int count = 0;

int add(int num) {
    if (count < 100) {
        buffer[count] = num;
        count++;
    }
    return 0;
}

int out() {
    int i;
    for (i = 0; i < count; i++) {
        printf("%d
", buffer[i]);
    }
    return 0;
}

• test_map.py

#!/usr/bin/python
#coding=utf8

import sys 
from ctypes import *

so = './test.so'
cdll.LoadLibrary(so)
api = CDLL(so)
api.add.argtypes = [c_int]
api.add.restype = c_int
api.out.argtypes = []
api.out.restype = c_int

for line in sys.stdin:
    if line.find("100013221") != -1:
        v = line.strip().split('	')
        api.add(int(v[1]))
    
api.out()

• test_red.py

#!/usr/bin/python
#coding=utf8

import sys 

for line in sys.stdin:
    sys.stdout.write(line)

• test.sh

hadoop jar $streaming 
-Dmapred.reduce.tasks=1 
-Dmapred.output.compress=true 
-Dmapred.output.compression.codec=com.hadoop.compression.lzo.LzoCodec 
-Dmapred.output.compression.type=BLOCK 
-Dmapred.compress.map.output=true 
-Dmapred.map.output.compression.codec=com.hadoop.compression.lzo.LzoCodec 
-input $input 
-output $output 
-mapper "test_map.py" 
-file test_map.py 
-reducer "test_red.py" 
-file test_red.py 
-file test.so

参考文献：

https://blog.csdn.net/frankie110/article/details/8724509/

http://www.isnowfy.com/introduction-to-python-c-extension/