使用Paramiko讀取Top命令的輸出

Question

我正在用Python寫一個腳本來登錄ssh並讀取剛剛執行的命令的輸出。 我正在使用paramiko包。 我正在嘗試執行命令“top”並在控制台上打印其輸出。 但是，我無法做到這一點。 請找到代碼段：

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()

輸出：嘗試連接到localhost（1/30）

連接到localhost

Linux的

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

Linux的

---

命令完成，關閉SSH連接

我不確定，我做錯了什么。 我能夠獲得其他linux命令的輸出。 但不確定，為什么top命令的輸出沒有打印出來。

Answer 1

正如Jason S指出的那樣

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

工作得很好。

Answer 2

top通常使用curses進行顯示而不僅僅是打印。 嘗試使用-b作為批處理選項以及您擁有的-n 1 （頂部選項因平台而異，請查看聯機幫助頁）。 並且在將來，嘗試更多地隔離問題 - 如果您在命令行top通過ssh調用top而沒有腳本，那么您仍然會遇到問題。