Question

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()

输出：尝试连接到localhost（1/30）

已连接到localhost

Linux的

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

Linux的

命令已完成，关闭SSH连接

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命令的输出没有打印出来。

Answer 1

top通常使用curses进行显示而不仅仅是打印。尝试-b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top调用ssh而没有您的脚本，那么您仍会遇到问题。

Answer 2

Jason S指出

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

工作正常。

使用Paramiko读取Top命令的输出

已连接到localhost

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

2 个答案: