问题:如何使用Paramiko获取SSH返回码?
client = paramiko.SSHClient()
stdin, stdout, stderr = client.exec_command(command)
有什么方法可以获取命令返回码?
很难解析所有stdout / stderr并知道命令是否成功完成。
client = paramiko.SSHClient()
stdin, stdout, stderr = client.exec_command(command)
Is there any way to get the command return code?
It’s hard to parse all stdout/stderr and know whether the command finished successfully or not.
回答 0
SSHClient是一个简单的包装类,围绕着Paramiko中的更底层功能。该API文档列出recv_exit_status()
的方法Channel
类。
一个非常简单的演示脚本:
import paramiko
import getpass
pw = getpass.getpass()
client = paramiko.SSHClient()
client.set_missing_host_key_policy(paramiko.WarningPolicy())
client.connect('127.0.0.1', password=pw)
while True:
cmd = raw_input("Command to run: ")
if cmd == "":
break
chan = client.get_transport().open_session()
print "running '%s'" % cmd
chan.exec_command(cmd)
print "exit status: %s" % chan.recv_exit_status()
client.close()
执行示例:
$ python sshtest.py
Password:
Command to run: true
running 'true'
exit status: 0
Command to run: false
running 'false'
exit status: 1
Command to run:
$
SSHClient is a simple wrapper class around the more lower-level functionality in Paramiko. The API documentation lists a recv_exit_status()
method on the Channel
class.
A very simple demonstration script:
import paramiko
import getpass
pw = getpass.getpass()
client = paramiko.SSHClient()
client.set_missing_host_key_policy(paramiko.WarningPolicy())
client.connect('127.0.0.1', password=pw)
while True:
cmd = raw_input("Command to run: ")
if cmd == "":
break
chan = client.get_transport().open_session()
print "running '%s'" % cmd
chan.exec_command(cmd)
print "exit status: %s" % chan.recv_exit_status()
client.close()
Example of its execution:
$ python sshtest.py
Password:
Command to run: true
running 'true'
exit status: 0
Command to run: false
running 'false'
exit status: 1
Command to run:
$
回答 1
一个更简单的示例,该示例不涉及直接调用“较低级别”的通道类(即- 不使用client.get_transport().open_session()
命令):
import paramiko
client = paramiko.SSHClient()
client.set_missing_host_key_policy(paramiko.AutoAddPolicy())
client.connect('blahblah.com')
stdin, stdout, stderr = client.exec_command("uptime")
print stdout.channel.recv_exit_status() # status is 0
stdin, stdout, stderr = client.exec_command("oauwhduawhd")
print stdout.channel.recv_exit_status() # status is 127
A much easier example that doesn’t involve invoking the “lower level” channel class directly (i.e. – NOT using the client.get_transport().open_session()
command):
import paramiko
client = paramiko.SSHClient()
client.set_missing_host_key_policy(paramiko.AutoAddPolicy())
client.connect('blahblah.com')
stdin, stdout, stderr = client.exec_command("uptime")
print stdout.channel.recv_exit_status() # status is 0
stdin, stdout, stderr = client.exec_command("oauwhduawhd")
print stdout.channel.recv_exit_status() # status is 127
回答 2
感谢JanC,我为示例添加了一些修改并在Python3中进行了测试,这对我来说真的很有用。
import paramiko
import getpass
pw = getpass.getpass()
client = paramiko.SSHClient()
client.set_missing_host_key_policy(paramiko.WarningPolicy())
#client.set_missing_host_key_policy(paramiko.AutoAddPolicy())
def start():
try :
client.connect('127.0.0.1', port=22, username='ubuntu', password=pw)
return True
except Exception as e:
#client.close()
print(e)
return False
while start():
key = True
cmd = input("Command to run: ")
if cmd == "":
break
chan = client.get_transport().open_session()
print("running '%s'" % cmd)
chan.exec_command(cmd)
while key:
if chan.recv_ready():
print("recv:\n%s" % chan.recv(4096).decode('ascii'))
if chan.recv_stderr_ready():
print("error:\n%s" % chan.recv_stderr(4096).decode('ascii'))
if chan.exit_status_ready():
print("exit status: %s" % chan.recv_exit_status())
key = False
client.close()
client.close()
Thanks for JanC, I added some modification for the example and tested in Python3, it really useful for me.
import paramiko
import getpass
pw = getpass.getpass()
client = paramiko.SSHClient()
client.set_missing_host_key_policy(paramiko.WarningPolicy())
#client.set_missing_host_key_policy(paramiko.AutoAddPolicy())
def start():
try :
client.connect('127.0.0.1', port=22, username='ubuntu', password=pw)
return True
except Exception as e:
#client.close()
print(e)
return False
while start():
key = True
cmd = input("Command to run: ")
if cmd == "":
break
chan = client.get_transport().open_session()
print("running '%s'" % cmd)
chan.exec_command(cmd)
while key:
if chan.recv_ready():
print("recv:\n%s" % chan.recv(4096).decode('ascii'))
if chan.recv_stderr_ready():
print("error:\n%s" % chan.recv_stderr(4096).decode('ascii'))
if chan.exit_status_ready():
print("exit status: %s" % chan.recv_exit_status())
key = False
client.close()
client.close()
回答 3
就我而言,输出缓冲是问题所在。由于存在缓冲,因此应用程序的输出不会以非阻塞方式输出。您可以在此处找到有关如何在不进行缓冲的情况下打印输出的答案:禁用输出缓冲。简而言之,只需使用-u选项运行python,如下所示:
> python -u script.py
In my case, output buffering was the problem. Because of buffering, the outputs from the application doesn’t come out non-blocking way. You can find the answer about how to print output without buffering in here: Disable output buffering. For short, just run python with -u option like this:
> python -u script.py