(Napalm Automation)在测试使用" with“打开文件/cisco开关时，使用try除块后出现缩进错误。

Question

获取IndentationError:应为缩进块

我故意尝试使用错误的凭据连接到设备，以测试身份验证异常。如果我删除了try块，并确保代码块是用正确的语法编写的enter code here，那么它运行得很好。这意味着程序会崩溃，就像它想要的那样。但是，如果我使用了正确的用户名和密码，它就可以正常工作。只有当我执行try块时，我才会得到上面的错误。

from napalm import get_network_driver
from getpass import getpass
from netmiko import NetMikoAuthenticationException


username = input('username')
password = getpass('password')
driver = get_network_driver('ios')
with open('devices.txt','r') as switch_db:
    for switch in switch_db:
    #set up to connect to a switch from switch_db
        try:
            with driver(switch, username, password) as device:

        except NetMikoAuthenticationException:
            print('Authentication Error!')

Answer 1

原来，我使用的with context管理器行被认为是一个空的try块，所以我更改了代码，以采取一个操作来设置连接调用的变量。当然，这是可行的，但您必须记住在您的代码中关闭连接。

from pprint import pprint
from napalm import get_network_driver
from getpass import getpass
from netmiko import NetMikoAuthenticationException
import json


username = input('username')
password = getpass('password')
driver = get_network_driver('ios')

with open('devices.txt','r') as switch_db:
    for switch in switch_db:
    #set up to connect to a switch from switch_db
        try:
            device = driver(switch, username, password)
            device.open()
        except NetMikoAuthenticationException:
            print('Authentication Error!')
            username = input('username')
            password = getpass('password')
            device = driver(switch, username, password)
            device.open()
        else:
            print('line after try block')
            pprint(device.get_interfaces())
            device.close()
            print('switch is closed')'

Answer 2

在这里回复，所以也可以看到这一点。

在try/except块中有一个空的with构造函数。这是可行的，并针对思科DevNet沙盒进行了测试。

#!/usr/bin/env python3

from napalm import get_network_driver
from getpass import getpass
from netmiko import NetMikoAuthenticationException
from napalm.base.exceptions import ConnectionException
from pprint import pprint


username = input('username: ')
password = getpass('password: ')
driver = get_network_driver('ios')
with open('devices.txt','r') as switch_db:
    for switch in switch_db:
    #set up to connect to a switch from switch_db
        try:
            with driver(switch, username, password, optional_args={'port': 8181}) as device:
                pprint(device.get_facts())
        except NetMikoAuthenticationException:
            print('Authentication Error!')
        except ConnectionException:
            print(f'Could not connect to {switch}')