SSH 连接不持久

Question

我有以下脚本，它通过 SSH 进入网络服务器并执行一些命令，由于某种原因，SSH 连接打开，但在执行命令时它关闭（我认为），因此命令失败并显示如下错误？谁能提供有关如何使 SSH 连接持久的信息？

#!/usr/bin/python
import os
import sys
import json
import fileinput
import pwd
from subprocess import Popen, PIPE, STDOUT
import re
import paramiko
import MySQLdb

resource = r'qca-cdit-01'
ssh = paramiko.SSHClient()
ssh.load_system_host_keys()
ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy())
ssh.connect(resource, username='username', password='passwordname')
#chan = ssh.get_transport().open_session()
chan = ssh.invoke_shell()
chan.get_pty()

commandstringlist = \
    ['/local/mnt/workspace/LA_host_builds/AU_LINUX_ANDROID_LA.BF64.1.2.1_RB2.05.01.01.081.031_msm8992',
     'cd frameworks/base',
     'git fetch ssh://cdit@review-android.company.com:29418/platform/frameworks/base refs/changes/21/1260821/2 && git cherry-pick FETCH_HEAD']
for cmd_val in commandstringlist:
    #chan.exec_command(cmd_val)
    chan.send(cmd_val)
    print(chan.recv(1024))

错误：

Traceback (most recent call last):
  File "ssh_test.py", line 21, in <module>
    chan.get_pty()
  File "/usr/local/lib/python2.7/dist-packages/paramiko/channel.py", line 60, in _check
    return func(self, *args, **kwds)
  File "/usr/local/lib/python2.7/dist-packages/paramiko/channel.py", line 177, in get_pty
    self._wait_for_event()
  File "/usr/local/lib/python2.7/dist-packages/paramiko/channel.py", line 1086, in _wait_for_event
    raise e
paramiko.ssh_exception.SSHException: Channel closed

Answer 1

谁能提供有关如何使 SSH 连接持久的信息？

以下是如何通过尝试执行命令然后在发生错误时返回连接然后执行命令来使 SSH 连接持久的示例。

import paramiko

class sshConnection:
  def __init__( self, host, un, pw ):
    self.host = host
    self.un = un
    self.pw = pw

  def connect( self ):
    self.ssh = paramiko.SSHClient()
    self.ssh.load_system_host_keys()
    self.ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy())
    self.ssh.connect(self.host, username=self.un, password=self.pw)

  def cmd ( self, cmd, tries=0 ):
    self.si, self.so, self.se = None, None, None
    try:
      self.si, self.so, self.se= self.ssh.exec_command(cmd)
    except Exception, e:
      if tries > 3:
        raise
      self.connect( )
      self.cmd(  cmd, tries+1 )
    return self.si, self.so, self.se



conn = sshConnection( "host","username","password" )

si, out, err = conn.cmd("ls -al")
print "\n".join(map ( lambda x: x.strip(), out.readlines()) )

Answer 2

只需做：

#!/usr/bin/python
import os
import sys
import json
import fileinput
import pwd
from subprocess import Popen, PIPE, STDOUT
import re
import paramiko
import MySQLdb

resource = r'qca-cdit-01'
ssh = paramiko.SSHClient()
ssh.load_system_host_keys()
ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy())
ssh.connect(resource, username='username', password='passwordname')
#chan = ssh.get_transport().open_session()
chan = ssh.invoke_shell()

commandstringlist = \
    ['\n/local/mnt/workspace/LA_host_builds/AU_LINUX_ANDROID_LA.BF64.1.2.1_RB2.05.01.01.081.031_msm8992\n',
     '\ncd frameworks/base\n',
     '\ngit fetch ssh://cdit@review-android.company.com:29418/platform/frameworks/base refs/changes/21/1260821/2 && git cherry-pick FETCH_HEAD\n']
for cmd_val in commandstringlist:
    #chan.exec_command(cmd_val)
    chan.send(cmd_val)
    print(chan.recv(8192))

这对我有用。 （你忘了 .send() 不会自动添加行）

Answer 3

诀窍是在执行命令之前切换到目录。您可以轻松地将其集成到您的execute_command：

def execute_command (cmd, pwd=None):
    if pwd:
        cmd = 'cd "%s";%s' % (pwd, cmd)
    print cmd
    si,so,se = ssh.exec_command(cmd) 
    print os.getcwd()
    print "printing so"
    soreadList = so.readlines()
    print soreadList
    print "printing se"
    errList = se.readlines()
    print errList

该命令由远程机器上的 shell 运行，因此也可以添加任何 shell 技巧，如设置环境变量。

Answer 4

您使用exec_command 执行的每个命令都有自己的通道，因此也有自己的上下文。该上下文包括工作目录。您在一个上下文中更改工作目录，然后尝试在另一个上下文中使用它。相反，对所有命令使用相同的通道。您可以打开一个通道并使用它，也可以一次发出所有命令。

commandstringlist = ['cd /local/mnt/workspace/test2 && cd data/log && git fetch ssh://username@review-android.company.com:29418/platform/data/log refs/changes/21/1260821/2 && git cherry-pick FETCH_HEAD']

这里还有一些其他问题应该更详细地解释这一点。

https://unix.stackexchange.com/questions/80821/why-does-cd-command-not-work-via-ssh https://superuser.com/questions/46851/keeping-working-directory-across-ssh https://stackoverflow.com/a/6770272/492773