Read sections from file with Python

Question

I'm trying to convert the cisco running configuration into parameters using python, and i'm stuck at reading configuration sections with python. Say for instance you have the below stanza:

!
interface Async1
 no ip address
 encapsulation slip
!       
router bgp 65500
 bgp router-id 1.1.1.1
 bgp log-neighbor-changes
 timers bgp 10 30
 neighbor 1.2.3.4 remote-as 1234
 neighbor 1.2.3.4 description Some Description
 neighbor 1.2.3.4 update-source GigabitEthernet0/0
 !
 address-family ipv4
  network 2.2.2.2 mask 255.255.255.255
  network 3.3.3.0 mask 255.255.255.252
  neighbor 1.2.3.4 activate
  neighbor 1.2.3.4 allowas-in 3
  neighbor 1.2.3.4 prefix-list PXL out
 exit-address-family
!
ip forward-protocol nd
no ip http server
no ip http secure-server
!

I want to read lines from 'router bgp' until first line that starts with '!' (e.g ^!), and then re-read the block to extract parameters into variables. A sample output would be:

router bgp 65500
 bgp router-id 1.1.1.1
 bgp log-neighbor-changes
 timers bgp 10 30
 neighbor 1.2.3.4 remote-as 1234
 neighbor 1.2.3.4 description Some Description
 neighbor 1.2.3.4 update-source GigabitEthernet0/0
 !
 address-family ipv4
  network 2.2.2.2 mask 255.255.255.255
  network 3.3.3.0 mask 255.255.255.252
  neighbor 1.2.3.4 activate
  neighbor 1.2.3.4 allowas-in 3
  neighbor 1.2.3.4 prefix-list PXL out
 exit-address-family
!

Note: I am able to extract the above code using awk or grep, but I want to translate my bash code to Python.

Thanks!

It may be useful for you to read this question and answer about using a customer field separator. [link](https://stackoverflow.com/questions/19600475/how-to-read-records-terminated-by-custom-separator-from-file-in-python) — T Burgis, Sep 04 '18 at 12:42

score 1 · Answer 1 · edited Feb 24 '19 at 15:46

1

Try this:

from ciscoconfparse import CiscoConfParse

bgp = confparse.find_blocks(r"^router bgp 65500")

edited Feb 24 '19 at 15:46

Moshe Slavin

5,127
5
23
38

answered Feb 24 '19 at 15:30

Anna Patil

31
3

score 0 · Answer 2 · answered Sep 04 '18 at 12:04

Thanks to another post on stackoverflow, I found a way to extract configuration sections from running config. Post is at Reading a file for a certain section in python.

Working code to extract "router bgp" section below:

bgp_found = False

bgp_section = []

with open('running-config', 'r') as f:
    for line in f.readlines():
        if 'router bgp' in line:
            bgp_found = True
            bgp_section.append(str(line).rstrip('\n'))  # this will append the section start to list
            continue
        if bgp_found:
            if line.startswith('!'):  # this will test if line starts with '!'
                bgp_found = False
            else:
                bgp_section.append(str(line).rstrip('\n'))
print (bgp_section)  # just for testing purposes; list would be used to extract rest of parameters

Hope it will be useful for others as well.

Read sections from file with Python

2 Answers2