Python 优雅的使用 paramiko 进行交互式输入输出
目的：需要ssh链接到Linux主机，执行telnet 命令，抓回显匹配制定内容。
ssh.exec_command(cmd,bufsize,timeout) #exec_command参数使用只需要执行一次的命令，因为执行完该命令以后，shell会自动回到ssh初始连接的shell状态下
ssh.invoke_shell() #在SSH server端创建一个交互式的shell，且可以按自己的需求配置伪终端，可以在invoke_shell()函数中添加参数配置
也就是command就是发送完指令，连接就会断开
invoke_shell则是长连接，保持状态的那种
import logging
import paramiko
import re
import select
import socket
PROMPT_PATTERN = r'\S+#'
logging.basicConfig(level=logging.DEBUG)
log = logging
paramiko.util.log_to_file('demo.log')
class Channel(object):
def __init__(self, host, commands, creds=None,
prompt_pattern=PROMPT_PATTERN, init_commands=None):
if creds is None:
raise RuntimeError('You must supply username and password!!')
self.host = host
self.commands = commands
username, password = creds
self.creds = creds
self.username = username
self.password = password
self.prompt = re.compile(prompt_pattern)
if init_commands is None:
init_commands = []
self.init_commands = init_commands
self.results = []
ssh = paramiko.SSHClient()
ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy())
self.ssh = ssh
self.initialized = False
self.record = False
def run(self):
"""
This is what we call do actually connect and start the event loop
"""
# Establish the SSH connection
self.ssh.connect(self.host, username=self.username,
password=self.password)
# Create an SSH shell descriptor. This is how we're going to interact
# with the remote device.
shell = self.ssh.invoke_shell()
shell.settimeout(0.0)
self.shell = shell
# Turn the list of commands into an iterator, so we know when we've run
# out of commands
self.cmditer = iter(self.commands)
# Establish the data buffer we'll use to store output between commands
self.data = ''
# And start the event loop to store the results of the commands and
# return them when we're done.
results = self.interact()
return results
def interact(self):
"""Interact with the device using the SSH shell."""
shell = self.shell
# Start an infinite while loop, and use the select.select async I/O
# handler to detect when data has been received by the SSH shell.
while True:
# The ``r`` variable names the object that has received data. See:
# http://docs.python.org/2/library/select.html#select.select
r, w, e = select.select([shell], [], [])
# If 'shell' has received data, try to retreive it:
if shell in r:
#log.debug("HEY LET'S DO SOMETHING WITH SHELL")
try:
# Fetch 1K off the socket.
bytes = shell.recv(1024).decode('utf-8', 'ignore').strip()
# If it's no data, we're done.
if len(bytes) == 0:
break
# Try to process the data we received.
self.data_received(bytes)
# If we timeout or get an error, log it and carry on.
except (socket.timeout, socket.error) as err:
log.error(str(err))
# If the socket has not received any data after we sent somethign,
# disconnect.
else:
break
# The explicit call to disconnect
shell.close()
# And finally return the output of the results.
return self.results
def data_received(self, bytes):
"""
This is what we do when data is received from the socket.
:param bytes:
Bytes that are received.
"""
# This is our buffer. Until we get a result we want, we keep appending
# bytes to the data buffer.
log.debug('Got bytes: %r' % bytes)
self.data += bytes
log.debug(' Buffered: %r' % self.data)
# Check if the prompt pattern matches. Return None if it doesn't so the
# event loop continues to try to receive data.
#
# Basicaly this means:
# - Loop until the prompt matches
# - Trim off the prompt
# - Store the buffer as the result of the last command sent
# - Zero out the buffer
# - Rinse/repeat til all commands are sent and results stored
m = self.prompt.search(self.data)
if not m:
return None
# log.debug('STATE: prompt %r' % m.group())
# The prompt matched! Strip the prompt from the match result so we get
# the data received withtout the prompt. This is our result.
#
result = self.data[:m.start()]
# result = result[result.find('\n')+1:]
result = result.splitlines()
# Only keep results once we've started sending commands
if self.initialized:
self.results.append(result)
# And send the next command in the stack.
self.send_next()
def send_next(self):
"""
Send the next command in the command stack.
"""
# We're sending a new command, so we zero out the data buffer.
self.data = ''
# Check if we can safely initialize. This is a chance to do setup, such
# as turning off console paging, or changing up CLI settings.
if not self.initialized:
if self.init_commands:
next_init = self.init_commands.pop(0)
self.shell.send(next_init)
return None
else:
log.debug('Successfully initialized for command execution')
self.initialized = True
# Try to fetch the next command in the stack. If we're out of commands,
# close the channel and disconnect.
try:
next_command = next(self.cmditer) # Get the next command
except StopIteration:
self.close() # Or disconnect
return None
# Try to send the next command
if next_command is None:
self.results.append(None) # Store a null command w/ null result
self.send_next() # Fetch the next command
else:
log.debug('sending %r' % next_command)
self.shell.send(next_command + '\n') # Send this command
def close(self):
"""Close the SSH connection."""
self.ssh.close()
if __name__ == '__main__':
commands = ['df -h\n', 'top -b -n 1\n']
host = '192.168.211.100'
username = 'root'
password = 'root'
creds = (username, password)
prompt_pattern = r'#|\S+ $|\S+ #'
init_commands = ['telnet 192.168.118.2\n', 'su\n']
c = Channel(host, commands, creds, prompt_pattern, init_commands)
results = c.run()
print(results)
