[1].[代码] [Python]代码

# -*- coding: GBK -*-

import urlparse

import datetime

import os

from multiprocessing import Process,Queue,Array,RLock

"""

多进程分块读取文件

"""

WORKERS = 4

BLOCKSIZE = 100000000

FILE_SIZE = 0

def getFilesize(file):

"""

获取要读取文件的大小

"""

global FILE_SIZE

fstream = open(file,'r')

fstream.seek(0,os.SEEK_END)

FILE_SIZE = fstream.tell()

fstream.close()

def process_found(pid,array,file,rlock):

global FILE_SIZE

global JOB

global PREFIX

"""

进程处理

Args:

pid:进程编号

array:进程间共享队列，用于标记各进程所读的文件块结束位置

file:所读文件名称

各个进程先从array中获取当前最大的值为起始位置startpossition

结束的位置endpossition (startpossition+BLOCKSIZE) if (startpossition+BLOCKSIZE)

if startpossition==FILE_SIZE则进程结束

if startpossition==0则从0开始读取

if startpossition!=0为防止行被block截断的情况，先读一行不处理，从下一行开始正式处理

if 当前位置 <=endpossition 就readline

否则越过边界，就从新查找array中的最大值

"""

fstream = open(file,'r')

while True:

rlock.acquire()

print 'pid%s'%pid,','.join([str(v) for v in array])

startpossition = max(array)

endpossition = array[pid] = (startpossition+BLOCKSIZE) if (startpossition+BLOCKSIZE)

rlock.release()

if startpossition == FILE_SIZE:#end of the file

print 'pid%s end'%(pid)

break

elif startpossition !=0:

fstream.seek(startpossition)

fstream.readline()

pos = ss = fstream.tell()

ostream = open('/data/download/tmp_pid'+str(pid)+'_jobs'+str(endpossition),'w')

while pos

#处理line

line = fstream.readline()

ostream.write(line)

pos = fstream.tell()

print 'pid:%s,startposition:%s,endposition:%s,pos:%s'%(pid,ss,pos,pos)

ostream.flush()

ostream.close()

ee = fstream.tell()

fstream.close()

def main():

global FILE_SIZE

print datetime.datetime.now().strftime("%Y/%d/%m %H:%M:%S")

file = "/data/pds/download/scmcc_log/tmp_format_2011004.log"

getFilesize(file)

print FILE_SIZE

rlock = RLock()

array = Array('l',WORKERS,lock=rlock)

threads=[]

for i in range(WORKERS):

p=Process(target=process_found, args=[i,array,file,rlock])

threads.append(p)

for i in range(WORKERS):

threads[i].start()

for i in range(WORKERS):

threads[i].join()

print datetime.datetime.now().strftime("%Y/%d/%m %H:%M:%S")

if __name__ == '__main__':

main()