#iotop是一个python编写的命令行下图形展示磁盘占用率的工具，学习python，看看他的源码，记录一下
#主程序文件 iotop
#__future__ 可调用新版本的一些模块使用
from __future__ import print_function
#导入系统模块
import sys
#try..except..else用法
#try..except语句来处理异常。我们把通常的语句放在try-块中，而把我们的错误处理语句放在except-块中,执行完try后，执行else中的try语句。
try:
#导入了main函数
from iotop.ui import main
except ImportError as e:
print(e)
print('To run an uninstalled copy of iotop,')
print('launch iotop.py in the top directory')
else:
try:
#执行main函数
main()
except KeyboardInterrupt:
pass
sys.exit(0)
#分析ui模块里的main，如下
#定义了用法的变量
USAGE = '''%s [OPTIONS]
DISK READ and DISK WRITE are the block I/O bandwidth used during the sampling
period. SWAPIN and IO are the percentages of time the thread spent respectively
while swapping in and waiting on I/O more generally. PRIO is the I/O priority at
which the thread is running (set using the ionice command).
Controls: left and right arrows to change the sorting column, r to invert the
sorting order, o to toggle the --only option, p to toggle the --processes
option, a to toggle the --accumulated option, i to change I/O priority, q to
quit, any other key to force a refresh.''' % sys.argv[0]
#main函数
def main():
try:
#设置语系
locale.setlocale(locale.LC_ALL, '')
except locale.Error:
print('unable to set locale, falling back to the default locale')
#optparse 命令行模块
#action的方法有store_true append
#add_option添加命令行参数
parser = optparse.OptionParser(usage=USAGE, version='iotop ' + VERSION)
parser.add_option('-o', '--only', action='store_true',
dest='only', default=False,
help='only show processes or threads actually doing I/O')
parser.add_option('-b', '--batch', action='store_true', dest='batch',
help='non-interactive mode')
parser.add_option('-n', '--iter', type='int', dest='iterations',
metavar='NUM',
help='number of iterations before ending [infinite]')
parser.add_option('-d', '--delay', type='float', dest='delay_seconds',
help='delay between iterations [1 second]',
metavar='SEC', default=1)
parser.add_option('-p', '--pid', type='int', dest='pids', action='append',
help='processes/threads to monitor [all]', metavar='PID')
parser.add_option('-u', '--user', type='str', dest='users', action='append',
help='users to monitor [all]', metavar='USER')
parser.add_option('-P', '--processes', action='store_true',
dest='processes', default=False,
help='only show processes, not all threads')
parser.add_option('-a', '--accumulated', action='store_true',
dest='accumulated', default=False,
help='show accumulated I/O instead of bandwidth')
parser.add_option('-k', '--kilobytes', action='store_true',
dest='kilobytes', default=False,
help='use kilobytes instead of a human friendly unit')
parser.add_option('-t', '--time', action='store_true', dest='time',
help='add a timestamp on each line (implies --batch)')
parser.add_option('-q', '--quiet', action='count', dest='quiet', default=0,
help='suppress some lines of header (implies --batch)')
parser.add_option('--profile', action='store_true', dest='profile',
default=False, help=optparse.SUPPRESS_HELP)
#调用 parse_args() 来解析程序的命令行
options, args = parser.parse_args()
if args:
parser.error('Unexpected arguments: ' + ' '.join(args))
#find_uids，判断用户的UID函数
find_uids(options)
####################################################################
#根据获得用户的值，获取UID
def find_uids(options):
"""Build options.uids from options.users by resolving usernames to UIDs"""
#定义一个序列
options.uids = []
error = False
for u in options.users or []:
try:
uid = int(u)
except ValueError:
try:
#
passwd = pwd.getpwnam(u)
except KeyError:
print('Unknown user:', u, file=sys.stderr)
error = True
else:
uid = passwd.pw_uid
if not error:
#把uid加入到序列里
options.uids.append(uid)
if error:
sys.exit(1)
####################################################################
options.pids = options.pids or []
options.batch = options.batch or options.time or options.quiet
main_loop = lambda: run_iotop(options)
if options.profile:
def safe_main_loop():
try:
main_loop()
except:
pass
_profile(safe_main_loop)
else:
main_loop()
