Return Multiple Serial Numbers from Cisco Devices - regex

Question

I am parsing the show version command for a series of information. Maybe there is any easier way, but I am trying to return all the serial numbers for devices in a stack. Currently I am only getting back the active switches serial number. Also I need to search through multiple areas for the serial number. Both Processor Board ID and System Serial Number.
I have tested the following Regex strings on https://regex101.com,
.*?^System\sSerial\sNumber\s
^System Serial Number\s([^,]+)
But in my code they do not seem to be working. When I print my variable it is showing empty for all iterations through the For loop.
#!/usr/bin/python
from getpass import getpass
import netmiko
import re
def make_connection (ip, username, password):
return netmiko.ConnectHandler(device_type='cisco_ios', ip=ip,
username=username, password=password)
def get_ip (input):
return(re.findall(r'(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?).){3}
(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)', input))
def get_ips (file_name):
#with does all the cleanup and prework of file open for you
with open(file_name, 'r') as in_file:
for line in in_file:
#this is probably supposed to be lineips = get_ip(line)
#line = get_ip(line)
lineips = get_ip(line)
for ip in lineips:
ips.append(ip)
def to_doc_a(file_name, varable):
f=open(file_name, 'a')
f.write(str(varable))
f.write('\n')
f.close()
def to_doc_w(file_name, varable):
f=open(file_name, 'w', newline="\n")
f.write(str(varable))
f.close()
#This will be a list of the devices we want to SSH to
ips = []
#Pull the IPs.txt is a list of the IPs we want to connect to
#This function pulls those IPs out of the txt file and puts them into a
#list
get_ips('IPs.txt')
#list where informations will be stored
#devices = []
#Results string storage
strresults = ""
#Prompt user for account info
username = input("Username: ")
password = getpass()
file_name = "results.csv"
#Clearing all the old info out of the results.csv file
to_doc_w(file_name, "")
#Make a for loop to hit all the devices, for this we will be looking at
#the IOS it’s running
for ip in ips:
#Connect to a device
net_connect = make_connection(ip, username, password)
#Run a command and set that to output
output = net_connect.send_command('show version')
#finding hostname in output using regular expressions
regex_hostname = re.compile(r'(\S+)\suptime')
hostname = regex_hostname.findall(output)
#finding uptime in output using regular expressions
regex_uptime = re.compile(r'\S+\suptime\sis\s(.+)')
uptime = regex_uptime.findall(output)
#finding version in output using regular expressions
regex_version = re.compile(r'Cisco\sIOS\sSoftware.+Version\s([^,]+)')
version = regex_version.findall(output)
#finding serial in output using regular expressions
regex_serial = re.compile(r'Processor\sboard\sID\s(\S+)')
serial = regex_serial.findall(output)
#finding serial in output using regular expressions
regex_serial2 = re.compile(r'^System Serial Number\s([^,]+)')
serial2 = regex_serial2.findall(output)
print(serial2)
#finding ios image in output using regular expressions
#regex_ios = re.compile(r'System\s\image\s\file\sis\s"([^ "]+)')
#ios = regex_ios.findall(output)
#finding model in output using regular expressions
regex_model = re.compile(r'[Cc]isco\s(\S+).*memory.')
model = regex_model.findall(output)
#append results to table [hostname,uptime,version,serial,ios,model]
#devices.append([hostname[0], uptime[0], version[0], serial[0],
#model[0]])
results = (ip, hostname, version, serial, serial2, model)
#Store results for later, reduce calls to append file, greatly i
#ncrease performance
strresults = strresults + str(results) + "\n"
#Next we will append the output to the results file
#to_doc_a(file_name, results)
to_doc_w(file_name, strresults)
No matter what Cisco device I would like this to pull the serial number and if there are multiple devices in a stack return all the serial numbers for devices in the stack. Also it should return IP, hostname, Version of Code and Model.

Answer 1

For the System Serial Number, your pattern ^System Serial Number\s([^,]+) uses an anchor to assert the start of the string, starts with uppercase Serial Number and is missing a colon : after number.
You could update your pattern where (\S+) captures in a group matching 1+ times a non whitespace char. In your pattern you use [^,]+ to match not a comma, but that would also match a space or newline.
System serial number:\s(\S+)
Regex demo | Python demo