使用Paramiko读取Top命令的输出

I am writing a script in Python for login to ssh and read the output of commands just executed. I am using paramiko package for this. I am trying to execute command "top" and get its output printed on the console. However, I am not able to do this. Please find the snippet:

我正在用Python写一个脚本来登录ssh并读取刚刚执行的命令的输出。我正在使用paramiko包。我正在尝试执行命令“top”并在控制台上打印其输出。但是,我无法做到这一点。请找到代码段:

import sys
import time
import select
import paramiko

host = 'localhost'
i = 1

#
# Try to connect to the host.
# Retry a few times if it fails.
#
while True:
    print 'Trying to connect to %s (%i/30)' % (host, i)

    try:
        ssh = paramiko.SSHClient()
        ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy())
        ssh.connect(host, port=22, username='dummy', password='dummy')
        print "Connected to %s" % host
        break
    except paramiko.AuthenticationException:
        print "Authentication failed when connecting to %s" % host
        sys.exit(1)
    except:
        print "Could not SSH to %s, waiting for it to start" % host
        i += 1
        time.sleep(2)

    # If we could not connect within time limit
    if i == 30:
        print "Could not connect to %s. Giving up" % host
        sys.exit(1)

# Send the command (non-blocking)
stdin, stdout, stderr = ssh.exec_command("uname")

# Wait for the command to terminate
while not stdout.channel.exit_status_ready():
    # Only print data if there is data to read in the channel
    if stdout.channel.recv_ready():
        rl, wl, xl = select.select([stdout.channel], [], [], 0.0)
        if len(rl) > 0:
            # Print data from stdout
        print '-------------------------------'
            print stdout.channel.recv(1024)
        print '-------------------------------'

# Send the command (non-blocking)
stdin, stdout, stderr = ssh.exec_command("top -n 1")

# Wait for the command to terminate
while not stdout.channel.exit_status_ready():
    # Only print data if there is data to read in the channel
    if stdout.channel.recv_ready():
        rl, wl, xl = select.select([stdout.channel], [], [], 0.0)
        if len(rl) > 0:
            # Print data from stdout
        print '-------------------------------'
            print stdout.channel.recv(1024)
        print '-------------------------------'

# Send the command (non-blocking)
stdin, stdout, stderr = ssh.exec_command("uname")

# Wait for the command to terminate
while not stdout.channel.exit_status_ready():
    # Only print data if there is data to read in the channel
    if stdout.channel.recv_ready():
        rl, wl, xl = select.select([stdout.channel], [], [], 0.0)
        if len(rl) > 0:
            # Print data from stdout
        print '-------------------------------'
            print stdout.channel.recv(1024)
        print '-------------------------------'

#
# Disconnect from the host
#
print "Command done, closing SSH connection"
ssh.close()

Output: Trying to connect to localhost (1/30)

输出:尝试连接到localhost(1/30)

Connected to localhost

Linux

-------------------------------

Linux

Command done, closing SSH connection

命令完成,关闭SSH连接

I am not sure, where I am doing wrong. I am able to get output of other linux commands though. But not sure, why top command's output is not getting printed.

我不确定,我做错了。我能够获得其他linux命令的输出。但不确定,为什么top命令的输出没有被打印出来。

2 个解决方案

#1

top normally uses curses for display rather than just printing. Try the -b for batch option along with the -n 1 you have (top options vary by platform, check the manpage). And in the future, try isolating the problem more - if you were to invoke top via ssh on the command line without your script you would still have an issue.

top通常使用curses进行显示而不仅仅是打印。尝试使用-b作为批处理选项以及您拥有的-n 1(顶部选项因平台而异,请查看联机帮助页)。并且在将来,尝试更多地隔离问题 - 如果您在命令行上通过ssh调用top而没有脚本,那么您仍然会遇到问题。

#2

as Jason S pointed out

正如杰森S所指出的那样

stdin, stdout, stderr = ssh.exec_command("top -b -n1")
print stdout.read()

works just fine.

工作得很好。

#1

#2