python3: 无法从程序头到尾将控制台输出恢复为文件& pexpect.EOF 问题

Question

下面是我使用pexpect模块实现SSH登录功能的代码。

#!/usr/bin/env python
import pexpect
import sys

#use ssh to logon server
user="inteuser"           #username
host="146.11.85.xxx"      #host ip
password="xxxx"           #password
command="ls -l"           #list file on home/user directory
child = pexpect.spawn('ssh -l %s %s %s'%(user, host, command))
child.expect('password:')
child.sendline(password)
childlog = open('prompt.log',"ab")     # restore prompt log to file prompt.log
__console__ = sys.stdout               # make a backup of system output to console 
sys.stdout = childlog                  # print the system output to childlog
child.expect(pexpect.EOF)  
childlog.close() 
sys.stdout = __console__               # back to the original state of system output
print(child.before)                    # print the contents before match expect function

执行脚本后

[~/Liaohaifeng]$ python3 ssh_test.py
b' \r\ntotal 69636\r\n-rw-rw-r-- 1 inteuser inteuser      949 Nov 28 02:01 
01_eITK_trtest01_CrNwid.log\r\n


[~/Liaohaifeng]$ cat prompt.log

total 69412
-rw-rw-r-- 1 inteuser inteuser      949 Nov 28 02:01 01_eITK_trtest01_CrNwid.log

我觉得这个结果出乎我的意料。当我删除脚本中的代码 child.expect(pexpect.EOF) 时，关于 print(child.before) 的输出可以是正确的（它应该在匹配 password 之前打印内容）

下面是我删除child.expect(pexpect.EOF)

后的输出

[~/Liaohaifeng]$ python3 ssh_test.py
b"\r\n-------------------------------------------------------------------------------\r\n...
These computer resources are provided for authorized users only. For legal,
\r\n
security and cost reasons, utilization and access of resources are sxx, in\r\n
accordance with approved internal procedures, at any time if IF YOU ARE NOT AN AUTHORIZED USER; PLEASE EXIT IMMEDIATELY...\r\n "

我的目的是在执行脚本后将所有输出打印到文件中，但日志文件仍然只包含列表目录的输出。那为什么会这样呢？你能帮我更新一下脚本吗？非常感谢。

Answer 1

您可以使用 spawn().logfile_read.

[STEP 101] # cat example.py
import pexpect, sys

child = pexpect.spawn('bash --norc')
if sys.version_info[0] <= 2:
    # python2
    child.logfile_read = open('/tmp/pexpect.log', 'w')
else:
    # python3
    fp = open('/tmp/pexpect.log', 'w')
    child.logfile_read = fp.buffer

child.expect('bash-[.0-9]+[$#] ')

child.sendline('echo hello world')
child.expect('bash-[.0-9]+[$#] ')

child.sendline('exit')
child.expect(pexpect.EOF)
child.logfile_read.close()
[STEP 102] # python3 example.py
[STEP 103] # cat /tmp/pexpect.log
bash-4.4# echo hello world
hello world
bash-4.4# exit
exit
[STEP 104] #

Answer 2

一道简单的题，调整代码顺序即可。

#!/usr/bin/env python
import pexpect
import sys

#use ssh to logon server
user="inteuser"           #username
host="146.11.85.xxx"      #host ip
password="xxxx"           #password
command="ls -l"           #list file on home/user directory   
child = pexpect.spawn('ssh -l %s %s %s'%(user, host, command))
childlog = open('prompt.log',"ab")
child.logfile = childlog
child.expect('password:')
child.sendline(password)                                  
child.expect(pexpect.EOF)  
childlog.close()

python3: 无法从程序头到尾将控制台输出恢复为文件& pexpect.EOF 问题

python3: can't restore the out on console to a file from the program beginning to end& pexpect.EOF issue

pexpect

python-3.x