如何使用netmiko连接串口？答案

【问题标题】：How to connect serial port using netmiko?如何使用netmiko连接串口？
【发布时间】：2018-02-13 04:55:15
【问题描述】：

我正在尝试连接到串行端口（COM7），但似乎无法正常工作。也许我在设备中做了错误的描述。谁能帮帮我？

from __future__ import absolute_import, division, print_function
import netmiko

device = {
"device_type": "cisco_ios_serial",
"port": "COM7",
"username": "admin",
"password": "",
"secret": "secret"
}

conn = netmiko.ConnectHandler(**device)
conn.enable()
output = conn.send_config_set([
        'no service dhcp',
        'service dhcp',
        'ip dhcp option format circuit_id',
        'attr 3 type 0 length-hidden 6 value string 2412533'])
print(output)
conn.disconnect()

这是错误

Traceback (most recent call last):
  File "test.py", line 12, in <module>
    conn = netmiko.ConnectHandler(**device)
  File "C:\Python\Python27\lib\site-packages\netmiko\ssh_dispatcher.py", line 173, in ConnectHandler
    return ConnectionClass(*args, **kwargs)
  File "C:\Python\Python27\lib\site-packages\netmiko\base_connection.py", line 117, in __init__
    self.port = int(port)
ValueError: invalid literal for int() with base 10: 'COM7'

【问题讨论】：

看来端口应该只是一个数字。

标签： python networking

【解决方案1】：

串行设置在设备定义的 serial_settings 中指定。

device = {
"device_type": "cisco_ios_serial",
"username": "admin",
"password": "",
"secret": "secret",
"serial_settings": {"port": "COM7"}
}

我没有要测试的串行设备，但在寻找 COM 端口时出错。

ValueError: device COM7 not found.

而不是期待一个整数。

来自 netmiko 源的 serial_settings 的默认值为：

    self.serial_settings = {
        'port': 'COM1',
        'baudrate': 9600,
        'bytesize': serial.EIGHTBITS,
        'parity': serial.PARITY_NONE,
        'stopbits': serial.STOPBITS_ONE
    }

来自https://github.com/ktbyers/netmiko/blob/develop/netmiko/base_connection.py

【讨论】：

【解决方案2】：

感谢您提供使用 serial_settings 的想法。但是，下面的 serial_settings 还有一些其他错误；仅供参考，我可以使用 USB 控制台访问 COM7，但出现错误。

Traceback (most recent call last):
  File "d:\Programming\GTAC\test_automation\test\robot_test\test.py", line 15, in <module>
    conn = netmiko.ConnectHandler(**device)
  File "C:\Python\Python27\lib\site-packages\netmiko\ssh_dispatcher.py", line 173, in ConnectHandler
    return ConnectionClass(*args, **kwargs)
  File "C:\Python\Python27\lib\site-packages\netmiko\base_connection.py", line 146, in __init__
    comm_port = check_serial_port(comm_port)
  File "C:\Python\Python27\lib\site-packages\netmiko\utilities.py", line 173, in check_serial_port
    return cdc.split()[0]
AttributeError: 'ListPortInfo' object has no attribute 'split'

【讨论】：

【解决方案3】：

check_serial_port 函数中存在试图拆分 ListPortInfo 对象的错误。快速解决方案是这样的猴子补丁：

import netmiko
import serial.tools.list_ports

def my_check_serial_port(name):
    """returns valid COM Port."""
    try:
        cdc = next(serial.tools.list_ports.grep(name))
        return cdc.__str__().split()[0]
    except StopIteration:
        msg = "device {} not found. ".format(name)
        msg += "available devices are: "
        ports = list(serial.tools.list_ports.comports())
        for p in ports:
            msg += "{},".format(str(p))
        raise ValueError(msg)

netmiko.base_connection.check_serial_port = my_check_serial_port

【讨论】：