网工Python——netdev（异步并行），举例看看ssh多台交换机执行命令异步和同步耗时对比实验：
代码简介：ssh两台华为交换机10.30.0.1和10.30.8.3，执行dis vlan summary，之后结算同步和异步耗时对比！
ip_list.txt文件内容是
同步方式的代码sshSW_tongbu.py，耗时40.34秒
from netmiko import ConnectHandler
import time
f = open('ip_list.txt')
start_time = time.time()
for ips in f.readlines():
ip = ips.strip()
SW = {
'device_type': 'huawei',
'ip': ip,
'username': 'admin@123',
'password': 'password123', #填写你的交换机密码
}
connect = ConnectHandler(**SW)
print ("Sucessfully connected to " + SW['ip'])
config_commands = ['dis vlan summary','quit']
output = connect.send_config_set(config_commands)
print (output)
print ('Time elapsed: %.2f'%(time.time()-start_time))
执行结果：
PS D:\Python_Files\python2020item\netdev_demo> python.exe .\sshSW_tongbu.py Sucessfully connected to 10.30.0.1 system-view Enter system view, return user view with Ctrl+Z. [S7706]dis vlan summary Static VLAN: Total 58 static VLAN. 1 3 10 37 50 to 55 80 to 85 101 to 116 201 to 203 300 400 to 402 801 to 805 900 999 to 1001 2001 2032 to 2039 4000 Dynamic VLAN: Total 0 dynamic VLAN. Reserved VLAN: Total 0 reserved VLAN. [S7706]quit <S7706> Sucessfully connected to 10.30.8.3 system-view Enter system view, return user view with Ctrl+Z. [S5700-3]dis vlan summary Static vlan: Total 25 static vlan. 1 50 to 54 101 to 115 1000 to 1001 1314 to 1315 Dynamic vlan: Total 0 dynamic vlan. Reserved vlan: Total 0 reserved vlan. [S5700-3]quit <S5700-3> Time elapsed: 40.34 PS D:\Python_Files\python2020item\netdev_demo>
异步方式的代码sshSW_tongbu.py，耗时12.69秒
import asyncio
import netdev
import time
async def task(dev):
async with netdev.create(**dev) as ios:
commands = ['dis vlan summary','quit']
out = await ios.send_config_set(commands)
print(out)
async def run():
devices = []
f = open('ip_list.txt')
for ips in f.readlines():
ip = ips.strip()
dev = { 'username' : 'admin@123',
'password' : 'password123', #填写你的交换机密码
'device_type': 'hp_comware', #华为 华三测试用这个type，因为没有huawei huasan关键字的type，netdev目前2020年仅支持它罗列的操作系统
'host': ip
}
devices.append(dev)
tasks = [task(dev) for dev in devices]
await asyncio.wait(tasks)
start_time = time.time()
asyncio.run(run())
print ('Time elapsed: %.2f'%(time.time()-start_time))
'''
备注：netdev目前2020年仅支持它罗列的操作系统
ValueError: Unsupported device_type: currently supported platforms are: arista_eos
aruba_aos_6
aruba_aos_8
cisco_asa
cisco_ios
cisco_ios_xe
cisco_ios_xr
cisco_nxos
fujitsu_switch
hp_comware
hp_comware_limited
hw1000
juniper_junos
mikrotik_routeros
terminal
ubiquity_edge
'''
执行结果：
PS D:\Python_Files\python2020item\netdev_demo> python.exe .\sshSW_yibu.py C:\Python38\lib\site-packages\asyncssh\crypto\ec.py:143: CryptographyDeprecationWarning: Support for unsafe construction of public numbers from encoded data will be removed in a future version. Please use EllipticCurvePublicKey.from_encoded_point pub = ec.EllipticCurvePublicNumbers.from_encoded_point(curve(), system-view Enter system view, return user view with Ctrl+Z. [ZD-CO-S7706]dis vlan summary Static VLAN: Total 58 static VLAN. 1 3 10 37 50 to 55 80 to 85 101 to 116 201 to 203 300 400 to 402 801 to 805 900 999 to 1001 2001 2032 to 2039 4000 Dynamic VLAN: Total 0 dynamic VLAN. Reserved VLAN: Total 0 reserved VLAN. [S7706]quit <S7706> system-view Enter system view, return user view with Ctrl+Z. [S7706]dis vlan summary Static VLAN: Total 58 static VLAN. 1 3 10 37 50 to 55 80 to 85 101 to 116 201 to 203 300 400 to 402 801 to 805 900 999 to 1001 2001 2032 to 2039 4000 Dynamic VLAN: Total 0 dynamic VLAN. Reserved VLAN: Total 0 reserved VLAN. [S7706]quit <S7706> system-view Enter system view, return user view with Ctrl+Z. [S5700-3]dis vlan summary Static vlan: Total 25 static vlan. 1 50 to 54 101 to 115 1000 to 1001 1314 to 1315 Dynamic vlan: Total 0 dynamic vlan. Reserved vlan: Total 0 reserved vlan. [S5700-3]quit <S5700-3> Time elapsed: 12.69 PS D:\Python_Files\python2020item\netdev_demo>
可以看出多台设备ssh并操作，异步方式耗时少很多，所以以后多用用异步，提高效率！！！
记得安装netdev，此外我看见安装netdev时候安装了asyncssh库，其实你看asyncssh的async的英文就是异步意思，就大概知道netdev有处理异步工作的相关能力了！