Ansible replace ip address using regex by looping through a file line by line

Question

I am new to ansible.

I have a file with multiple lines which has ipv4 address referenced in some lines. My use case is to replace the ipaddress in each of those lines with an incremented version of the same ip.

So if for example my file has lines as below:

The ip address in line is 10.1.1.1 and username test1

The ip address in line is 20.2.2.2 and username test2

I want to replace it as :

The ip address in line is 10.1.1.2 and username test1

The ip address in line is 20.2.2.3 and username test2

I am using the Ansible replace module to find ipv4 address in the line using regex and replace.

- name: Increment and Replace Ip address and
      replace:
        path: "config/changed-ip.txt"
        regexp: "{{ '([0-9]{1,3}[\\.]){3}[0-9]{1,3}' }}"
        replace: "{{ 'x.x.x.x' }}"

The above code replaces all ip address with the one I specified in the replace

Is there a way to extract the ip address from each line and increment it and replace the ipaddr in place of the old ip using any modules like lineinfile or replace?

I am running ansible 2.6

Answer 1

Try use this regex:

^(\d{1,3}\.){3}\d{1,3}

^ means start of string.

Answer 2

You can call a python script from the ansible playbook to execute the task you are interested in. The ipaddress module is useful if you want to do ip address arithmetics.

For instance:

---
  - hosts: all
    tasks:
    - command: "python3 process_ip_addresses.py text"

The accompanying python is:

from ipaddress import IPv4Address
import re
import sys

file_path = sys.argv[1]
with open(file_path) as f:
    text = f.read()

ip_addresses = re.findall( r'[0-9]+(?:\.[0-9]+){3}', text )
replacement_ip_addresses = [str(IPv4Address(address) + 1) for address in ip_addresses]
for old_address, new_addresss in zip(ip_addresses, replacement_ip_addresses):
    text = text.replace(old_address, new_addresss)

with open(file_path, "w") as f:
    f.write(text)