pexpect
秦景同
pexpect
spawn类
功能
- 启动和控制子应用程序
构造函数
-
class pexpect.spawn(command,args=[],timeout=30,maxread=2000,searchwindowsize=None,logfile=None,cwd=None,env=None,ignore_sighup=True)
- command：可以是任意已知的系统命令
- args：当子程序需要参数时，可以使用python列表来代替参数
- timeout：等待结果的超时时间
- maxread：是pexpect从终端控制台一次读取的最大字节数
- searchwindowsize：为匹配缓冲区字符串的位置（默认从头开始位置匹配）
- 注意：pexpect不会解析shell命令中的元字符（'>','|','*'）
-
child=pexpect.spawn('/bin/bash -c "ls -l|grep shell>shell.txt"')
child.expect(pexpect.EOF)
-
shell_cmd='ls -l |grep shell>shell.txt'
child=pexpect.spawn('/bin/bash',['-c',shell_cmd])
child.expect(pexpect.EOF)
获取pexpect的输入和输出
日志文件
-
child=pexpect('commands')
fout=file('log.txt','w')
child.logfile=fout
输出到标准输出
-
child=pexpect.spawn('commands')
child.logfile=sys.stdout
实例ssh
-
[root@server6 ~]# python ssh.py
Traceback (most recent call last):
File "ssh.py", line 2, in <module>
import pexpect
File "/root/pexpect.py", line 3, in <module>
AttributeError: 'module' object has no attribute 'spawn'
[root@server6 ~]# ls
anaconda-ks.cfg index.html other.py psutil-2.0.0
A.py initial-setup-ks.cfg passwd shell
CNAME.py localhost.53420: pexpecet-3.0.tar.gz shell.bak
cpu.py mem.py pexpect-3.0 sh.py
demo1.py MX.py pexpect.pyc ssh
Desktop net.py popen.py ssh.py
disk.py NS.py process.py
exports original-ks.cfg ps.py
[root@server6 ~]# rm -f pexpec.py
-
[root@server6 ~]# python ssh.py
[root@server6 ~]# cat mylog.txt
root@192.168.109.143's password: centos
Last login: Thu Aug 24 00:19:13 2017 from server6.example.com
[root@server7 ~]# ls /root
ls /root
anaconda-ks.cfg demo1.py initial-setup-ks.cfg net.py popen.py
A.py Desktop localhost.53420: NS.py process.py
CNAME.py disk.py mem.py original-ks.cfg ps.py
cpu.py exports MX.py other.py psutil-2.0.0
-
[root@server6 ~]# cat ssh.py
import sys
import pexpect
child=pexpect.spawn('ssh root@192.168.109.143')
fout=file('mylog.txt','w')
child.logfile=fout
child.expect('password:')
child.sendline('centos')
child.expect('#')
child.sendline('ls /root')
child.expect('#')
expect方法
- expect(pattern,timeout,searchwindowsize)
- 成员before
- 成员after
-
[root@server6 ~]# python ssh.py
before:root@192.168.109.143's
after:password:
[root@server6 ~]# cat ssh.py
import sys
import pexpect
child=pexpect.spawn('ssh root@192.168.109.143')
fout=file('mylog.txt','w')
child.logfile=fout
#child.expect('(yes/no)?')
#child.sendline('yes')
child.expect('password:')
child.sendline('centos')
print "before:"+child.before
print "after:"+child.after
- read
-
send(self,s)发送命令，不会车
sendline(self,s='')发送命令，回车
sendcontrol(self,char)发送控制符
sendof()发送eof
run函数
- 进行封装的调用外部命令的函数，类似os.system或os.popen;
- 使用run()可同时获得命令的输出结果及命令的退出状态 pexpect.run(command,timeout=-1,withexitstatus=False,events=None,extra_args=None,logfile=None.cwd=None,env=None)
- command：系统已知任意命令
- events：字典
-
[root@server6 ~]# cat test.py
from pexpect import *
run('scp ssh.py root@192.168.109.143:', events={'(?i)password' : 'centos\n'} )
[root@server6 ~]# python test.py
[root@server7 ~]# ls
tmp
[root@server7 ~]# ls
ssh.py tmp
派生类pxssh
功能
- 针对ssh会话操作上再做一层封装，提供与基类更加直接的操作方法
pxssh类定义
class pexpect.pxssh.pxssh(timeout=30,maxread=2000,searchwindowsize=None,logfile=None,cwd=None,env=None)
常用方法
- login()：建立ssh连接
- logout()：断开连接
- prompt()：等待系统提示符，用于等待命令执行结束
执行过程
- 使用login()方法与远程主机建立连接，再通过sendline()方法发送执行的命令，prompt()方法等待命令执行结束且出现系统提示符，最后使用logout()方法断开连接。
-
[root@server6 ~]# python test.py
hostname:192.168.109.143
username:root
please input password:
uptime
18:08:13 up 8:02, 2 users, load average: 0.06, 0.03, 0.05
ls -l
total 4
-rw-r--r-- 1 root root 277 Aug 24 17:30 ssh.py
drwxr-xr-x 5 root root 320 Aug 24 17:10 tmp
df
Filesystem 1K-blocks Used Available Use% Mounted on
/dev/sda3 18555904 6128564 12427340 34% /
devtmpfs 485292 0 485292 0% /dev
tmpfs 499968 100 499868 1% /dev/shm
tmpfs 499968 38528 461440 8% /run
tmpfs 499968 0 499968 0% /sys/fs/cgroup
/dev/sda1 303780 154756 149024 51% /boot
tmpfs 99996 16 99980 1% /run/user/42
tmpfs 99996 0 99996 0% /run/user/0
-
[root@server6 ~]# cat test.py
import pxssh
import getpass
try:
s=pxssh.pxssh()
hostname=raw_input('hostname:')
username=raw_input('username:')
password=getpass.getpass('please input password:')
s.login(hostname,username,password)
s.sendline('uptime')
s.prompt()# ？
print s.before
s.sendline('ls -l')
s.prompt()
print s.before
s.sendline('df')
s.prompt()
print s.before
s.logout()
except pxssh.ExceptionPxssh,e:
print "pxssh failed on login."
print str(e)
例子
- 实现自动化FTP操作
-
步骤1，在server6（192.168.109.142）搭建ftp
yum install -y vsftpd
步骤2，查看配置文件，匿名用户的权限（登录，下载）
anonymous_enable=YES
anon_upload_enable=YES
步骤3，开启服务
service vsftpd start
步骤4，准备测试文件
cd /var/ftp/pub
echo "hello">file.txt
- 手动到ftp服务器下载东西
-
[root@server7 ~]# ftp 192.168.109.142
Connected to 192.168.109.142 (192.168.109.142).
220 (vsFTPd 3.0.2)
Name (192.168.109.142:root): anonymous
331 Please specify the password.
Password:
230 Login successful.
Remote system type is UNIX.
Using binary mode to transfer files.
ftp> bin
200 Switching to Binary mode.
ftp> get file.txt
local: file.txt remote: file.txt
227 Entering Passive Mode (192,168,109,142,163,50).
550 Failed to open file.
ftp> ls
227 Entering Passive Mode (192,168,109,142,34,224).
150 Here comes the directory listing.
drwxr-xr-x 2 0 0 22 Aug 25 01:36 pub
226 Directory send OK.
ftp> cd pub
250 Directory successfully changed.
ftp> ls
227 Entering Passive Mode (192,168,109,142,98,198).
150 Here comes the directory listing.
-rw-r--r-- 1 0 0 6 Aug 25 01:36 file.txt
226 Directory send OK.
ftp> get file.txt
local: file.txt remote: file.txt
227 Entering Passive Mode (192,168,109,142,68,111).
150 Opening BINARY mode data connection for file.txt (6 bytes).
226 Transfer complete.
6 bytes received in 0.00144 secs (4.17 Kbytes/sec)
ftp> exit
221 Goodbye.
-
[root@server7 ~]# ls
file.txt ssh.py tmp
- 自动到pub目录下载指定文件
-
[root@server7 ~]# python ftp.py
226 Directory send OK.
ftp> get file.txt
local: file.txt remote: file.txt
227 Entering Passive Mode (192,168,109,142,22,117).
150 Opening BINARY mode data connection for file.txt (6 bytes).
226 Transfer complete.
6 bytes received in 0.000135 secs (44.44 Kbytes/sec)
ftp> exit
221 Goodbye.
- 一定要注意是否首次scp拷贝东西
-
[root@server7 ~]# cat ftp.py
from __future__ import unicode_literals
import pexpect
import sys
child=pexpect.spawnu('ftp server6')
child.sendline('anonymous')
child.expect('(?i)password')
child.sendline('\n')
child.expect('ftp>')
child.sendline('bin')
child.expect('ftp>')
child.sendline('dir')
if child.expect('pub')==0:
child.sendline('cd pub')
if child.expect('OK.')==0:
child.sendline('ls')
if child.expect('file.txt')==0:
child.sendline('get file.txt')
sys.stdout.flush()
child.sendline('exit')
child.interact()
child.close()
[root@server6 ~]# cat tar.py
import pexpect
import sys
ip="192.168.109.143"
user="root"
password="centos"
target_file="/etc/vsftpd/vsftpd.conf"
child=pexpect.spawn('/usr/bin/ssh',[user+'@'+ip])
fout=file('mylog.txt','w')
child.logfile=fout
try:
#if child.expect('(?i)id_rsa')==0:
# child.sendline('\n')
child.expect('(?i)password')
child.sendline(password)
child.expect('#')
child.sendline('tar -czf /tmp/vsftpd.tar.gz '+target_file)
child.expect('#')
child.sendline('exit')
fout.close()
except EOF:
print "except EOF"
except TIMEOUT:
print "expect TIMEOUT"
child=pexpect.spawn('/usr/bin/scp',[user+'@'+ip+':/tmp/vsftpd.tar.gz','/home'])
fout=file('mylog.txt','a')
child.logfile=fout
try:
#if child.expect('(?i)id_rsa')==0:
# child.sendline('\n')
child.expect('(?i)password')
child.sendline(password)
child.expect(pexpect.EOF)
except pexpect.EOF:
print "except EOF"
except TIMEOUT:
print "expect TIMEOUT"
- 结果
-
[root@server6 ~]# python tar.py
[root@server6 ~]# cat mylog.txt
root@192.168.109.143's password: centos
Last login: Thu Aug 24 23:36:38 2017 from server6.example.com
[root@server7 ~]# tar -czf /tmp/vsftpd.tar.gz /etc/vsftpd/vsftpd.conf
tar -czf /tmp/vsftpd.tar.gz /etc/vsftpd/vsftpd.conf
tar: Removing leading `/' from member names
[root@server7 ~]# exit
root@192.168.109.143's password: centos
vsftpd.tar.gz 0% 0 0.0KBvsftpd.tar.gz 100% 2302 2.3KB/s 00:00
[root@server7 home]# ls
centos ly vsftpd.tar.gz
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