使用 python 获取 httpd 程序所占用物理内存

#!/usr/bin/env python
#encoding: utf-8
'''
思路: /proc/xx_pid/status 文件中的关键字段 VmRSS 来获取某个进程占用的物理内存
步骤: 获取 httpd 进程ID列表 --> 通过每个进程id来获取该进程占用物理内存
'''

from subprocess import Popen, PIPE
import os,sys

# 通过程序名称获取 pid 列表
def getProgPids(prog):
    p = Popen(['pidof', prog], stdout=PIPE, stderr=PIPE)
    pids = p.stdout.read().split()
    return pids

# 通过具体的进程 id 来获取该进程占用的物理内存
def getMemByPid(pid):
    fn = os.path.join('/proc', pid, 'status')
    with open(fn) as fd:
        for line in fd:
            if line.startswith('VmRSS'):
                mem = int(line.split()[1])
                break
    return mem

# 获取 httpd 服务所有进程占用的物理内存
def getHttpdMem():
    httpd_mem_sum = 0
    pids = getProgPids('httpd')
    for pid in pids:
        httpd_mem_sum += getMemByPid(pid)

    return httpd_mem_sum

# 获取系统总的物理内存
def getOsTotalMemory():

    with open('/proc/meminfo') as fd:
        for line in fd:
            if line.startswith('MemTotal'):
                total_mem = int(line.split()[1])
                break
    return total_mem

if __name__ == '__main__':
    http_mem  =  getHttpdMem()
    total_mem =  getOsTotalMemory()

    scale = http_mem / float(total_mem) * 100
    print 'Httpd: %d KB' % http_mem
    print 'Percent: %.2f%%' % scale