Ansible regex replace in variable to cisco interface names - ansible

Question

I'm currently working with a script to create interface descriptions based on CDP neighbor info, but it's placing the full names e.g., GigabitEthernet1/1/1, HundredGigabitEthernet1/1/1.
My regex is weak, but I would like to do a regex replace to keep only the first 3 chars of the interface name.
I think a pattern like (dredGigatbitEthernet|abitEthernet|ntyGigabitEthernet|etc) should work, but not sure how to put that into the playbook line below to modify the port value
nxos_config:
lines:
- description {{ item.value[0].port }} ON {{ item.value[0].host }}
E.g, I am looking for GigabitEthernet1/1/1 to end up as Gig1/1/1
Here is an example of input data:
{
"FastEthernet1/1/1": [{
"host": "hostname",
"port": "Port 1"
}]
}
Final play to make it correct using ansible net neighbors as the source
Thank you - I updated my play, adjusted for ansible net neighbors
- name: Set Interface description based on CDP/LLDP discovery
hosts: all
gather_facts: yes
connection: network_cli
tasks:
- debug:
msg: "{{ ansible_facts.net_neighbors }}"
- debug:
msg: >-
description
{{
item[0].port
| regex_search('(.{3}).*([0-9]+\/[0-9]+\/[0-9]+)', '\1', '\2')
| join
}}
ON {{ item.value[0].host }}"
loop: "{{ ansible_facts.net_neighbors | dict2items }}"
loop_control:
label: "{{ item.key }}"
Thanks for the input!

Answer 1

Given that you want the three first characters along with the last 3 digits separated by a slash, then the regex (.{3}).*([0-9]+\/[0-9]+\/[0-9]+) should give you two capturing groups containing those two requirements.
In Ansible, you can use regex_search to extract those groups, then join them back, with the help on the join Jinja filter.
Given the playbook:
- hosts: localhost
gather_facts: no
tasks:
- debug:
msg: >-
description
{{
item.key
| regex_search('(.{3}).*([0-9]+\/[0-9]+\/[0-9]+)', '\1', '\2')
| join
}}
ON {{ item.value[0].host }}"
loop: "{{ interfaces | dict2items }}"
loop_control:
label: "{{ item.key }}"
vars:
interfaces:
GigabitEthernet1/1/1:
- port: Port 1
host: example.org
HundredGigabitEthernet1/1/1:
- port: Port 2
host: example.com
This yields:
TASK [debug] ***************************************************************
ok: [localhost] => (item=eth0) =>
msg: description Gig1/1/1 ON example.org"
ok: [localhost] => (item=eth1) =>
msg: description Hun1/1/1 ON example.com"