python pexpect 学习与探索

　

pexpect是python交互模块，有两种使用方法，一种是函数：run另外一种是spawn类

1.pexpect  module 安装
 

　　pexpect属于第三方的，所以需要安装，

      目前的版本是 3.3 下载地址 https://pypi.python.org/pypi/pexpect/

　　安装步骤：　　

　　　　

tar -xzvf  pexpect-3.3.tar.gz 
cd pexpect-3.3 
python setup install (require root)

但是 这个安装需要root权限，如果没有root权限在，还能使用吗？

　　答案是肯定的，你只需要把lib的路径放入sys.path。这样便可以使用pexpect

#!/usr/bin/env python
import sys
sys.path.append('pexpect-3.3/build/lib')
 

　　确认安装成功：

　　　　

>>> import pexpect
>>> dir(pexpect)
['EOF', 'ExceptionPexpect', 'PY3', 'TIMEOUT', '__all__', '__builtins__', '__doc__', '__file__', '__name__', '__package__', '__path__', '__revision__', '__version__', '_run', 'codecs', 'errno', 'fcntl', 'is_executable_file', 'os', 'pty', 're', 'resource', 'run', 'runu', 'searcher_re', 'searcher_string', 'select', 'signal', 'spawn', 'spawnu', 'split_command_line', 'stat', 'struct', 'sys', 'termios', 'time', 'traceback', 'tty', 'types', 'which']

2.使用方法

　　run 函数,run函数和os。system()差不多，所不同的是os.system返回的是整数，而run返回字符串

　　

>>> print pexpect.run('ping localhost -c 3')           
PING localhost (127.0.0.1) 56(84) bytes of data.
64 bytes from localhost (127.0.0.1): icmp_seq=1 ttl=64 time=0.087 ms
64 bytes from localhost (127.0.0.1): icmp_seq=2 ttl=64 time=0.088 ms
64 bytes from localhost (127.0.0.1): icmp_seq=3 ttl=64 time=0.088 ms

--- localhost ping statistics ---
3 packets transmitted, 3 received, 0% packet loss, time 2002ms
rtt min/avg/max/mdev = 0.087/0.087/0.088/0.010 ms

 spawn 类是通过生成子程序sendline发送命令与expect拿回返回进行交互

import pexpect
child = pexpect.spawn('python',timeout=3)
child.expect(">>>")
child.sendline("exit()")
print child.before   # Print the result of the ls command.

timeout是等待时间，如果超过就会抛出exception，可以 使用except关键字捕获

　　

设置log

fout=file('filename','a') #w write /a append
child = pexpect.spawn('su root')
child.logfile = sys.stdout
child.logfile_send=fout

　　

#!/usr/bin/python 
'''
this script can batch add user 
everytime will add specific usename
user mumber and password
create by Young 2014/08/02
require pexpect module, if you don't have one 
please install this module 
if you can't install this module please 
add  this module path to sys.path
'''
import pexpect
import getopt
import os
import sys
import random
import string

# usage fuction
def usage():
    print '''
Usage: python %s  --name user --amount 100 --password [optional]
or python %s  -n user -a 100 -p [optional]
this will create user1~user100 and default password will be random or specific.
make sure when you run this script as root 
-n,--name        the username you want create
-a,--amount      the amount of users you want create
-p,--password    the default password of use your create
-h,--help        display this help and exit
-v,--version     output version information and exit
'''  %(sys.argv[0],sys.argv[0])
# get the parameters 
# set the default user name
user_name='user'
# generate random password
def set_password():
    word=[x for x in 'aAbBcCdDeEfFgGhHiIjJkKlLmMnNoOpPqQrRsStTuUvVwWxXyYzZ0123456789']
    p=string.join(random.sample(word, 8)).replace(" ","")
    return p
# number of users ,set default users number as 10
number_of_users=10
password=set_password()
is_ramdom_password=True
#print password
def get_command():
    try:
        opts, args = getopt.getopt(sys.argv[1:], "n:a:p:hv", ["name=","amount=","password=","help", "version"])
    except getopt.GetoptError as err:
        # print help information and exit
        print str(err) # will print something like "option -a not recognized"
            usage()
            sys.exit(2)
    #print opts,args
    for option,value in opts:
        #print "----------->"+option+' <><>'+value
            if option in ["-n","--name"]:
            if(len(value)>=4):
                global user_name
                user_name=value
            else:
                print "invaild usename,will use user"
        elif option in ["-a","--amount"]:
            if value.isdigit():
                if( int(str(value))>0 and int(str(value))< 1000 ):
                    global number_of_users
                    number_of_users=int(str(value))
                else:
                    usage()
                    sys.exit(2)
            else:
                print "ValueError: invalid literal for ",value
                print "invaild amount,will use defualt"
        
        elif option in ["-p","--password"]:
            if(len(value)>=6):
                global password
                password=value    
                global is_ramdom_password
                is_ramdom_password=False
            else:
                print "invaild password,will use random"
        elif option in ["-v","--version"]:
                    print sys.argv[0]+' 1.0.0'
            sys.exit(0)
               elif option in ("-h", "--help"):
                    usage()
                    sys.exit(0)
               else :
            assert False, "unhandled option"
            usage()
            sys.exit(2)
def check_root():
    if( os.environ['USER']!='root'):
        print 'Permission denied,please su root'
        sys.exit()
#use pexpect to adduser
def run_add(user,mypassword):
    log = file('adduser.log','a')
    flag=os.system('adduser '+user)
    if(flag!=0):
        os.system('userdel '+user)
        os.system('adduser '+user)
    try:
        child=pexpect.spawn('passwd '+user,timeout=5)
        child.logfile = log
        child.logfile_send=sys.stdout 
        child.expect("New password:")
        child.sendline(mypassword)
        child.expect("Retype new password:")
        child.sendline(mypassword)
        child.expect("passwd: all authentication tokens updated successfully.")
    except pexpect.EOF:
        pass
    except pexpect.TIMEOUT:
        pass

    
def add_user(name,amount,password,is_ramdom_password):
    check_root()
    for number in range(1,amount+1):
        if(is_ramdom_password):
            print "%4d: adduser %s%-4d password %s " %(number,name,number,set_password())    
            run_add(name+str(number),set_password())
        else:
            print "%4d: adduser %s%-4d password %s " %(number,name,number,password)
            run_add(name+str(number),set_password)
        

get_command()
add_user(user_name,number_of_users,password,is_ramdom_password)