REGEX (regex_search) like Linux EGREP - Show pattern matching lines (with spaces) using multi-pattern/ range using one with_items loop

Ansible / ansible-playbook 2.9.27

I have the following playbook, and I want to show only those lines (from the data structure (i.e. list --> with_items loop) which match a given multi "egrep" like pattern (ex: "pattern1|pattern2|patter3withRange[0-9a-zA-Z]").

How can I achieve this purely in Ansible, possibly using just one with_items / loop?

It would be great:

if I don't have to use N no. of nested loops (per pattern/string) --or--
I don't have to use a shell one-liner code (egrep "string|ab.*yz|giga").

Here is my Playbook: aks.yml

---
- hosts: localhost
  become: yes
  remote_user: root
  become_user: root
  pre_tasks:
  - name: show pattern matching lines
    #command: 'echo {{ item }} | egrep -i "r[0-9]|goga"'
    ansible.builtin.debug:
      var: "{{ item }}"
    when: ( item | regex_search('r0[0-9]|goga', ignorecase=True))
    with_items:
      - "ar00n_giga"
      - "Schnooka_goga"
      - "lorito_r01_gigaFifa"

Running the playbook gives me:

$ ansible-playbook aks.yml

[WARNING]: provided hosts list is empty, only localhost is available. Note that the implicit localhost does not match 'all'

PLAY [localhost] *************************************************************************************************************************************************************************************************

TASK [Gathering Facts] *******************************************************************************************************************************************************************************************
ok: [localhost]

TASK [show pattern matching lines] *******************************************************************************************************************************************************************************
ok: [localhost] => (item=ar00n_giga) => {
    "ansible_loop_var": "item", 
    "ar00n_giga": "VARIABLE IS NOT DEFINED!", 
    "item": "ar00n_giga"
}

skipping: [localhost] => (item=Schnooka_goga) 

ok: [localhost] => (item=lorito_r01_gigaFifa) => {
    "ansible_loop_var": "item", 
    "item": "lorito_r01_gigaFifa", 
    "lorito_r01_gigaFifa": "VARIABLE IS NOT DEFINED!"
}

PLAY RECAP *******************************************************************************************************************************************************************************************************
localhost                  : ok=2    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0

I noticed both the "range" [0-9] and multi pattern i.e. using | within regex_search(...) worked!

using range r0[0-9] is successfully catching item strings containing both r00 and r01, which is great.
using ...|goga (it also catches 2nd line too, which doesn't have r0[0-9] pattern.

But the above code doesn't work if my values have spaces in the with_items: loop i.e. if I add the following:

with_items:
  - "ar00n_giga"
  - "new goga shooga"
  - "Schnooka_goga"
  - "lorito_r01_gigaFifa"

Then, I'm getting the following error message:

...
TASK [show pattern matching lines] *******************************************************************************************************************************************************************************
ok: [localhost] => (item=ar00n_giga) => {
    "ansible_loop_var": "item", 
    "ar00n_giga": "VARIABLE IS NOT DEFINED!", 
    "item": "ar00n_giga"
}
fatal: [localhost]: FAILED! => {"msg": "template error while templating string: expected token 'end of print statement', got 'goga'. String: {{new goga shooga}}"}

PLAY RECAP *******************************************************************************************************************************************************************************************************
localhost                  : ok=1    changed=0    unreachable=0    failed=1    skipped=0    rescued=0    ignored=0

Solution

On RHEL 7.9 with Ansible from the Red Hat Distribution Channel

ansible --version
ansible 2.9.27
...
  ansible python module location = /usr/lib/python2.7/site-packages/ansible
  executable location = /usr/bin/ansible
  python version = 2.7.5 (default, May 30 2023, 03:38:55) [GCC 4.8.5 20150623 (Red Hat 4.8.5-44)]

a minimal example playbook

---
- hosts: localhost
  become: false
  gather_facts: false

  vars:

    ITEMS:
      - "ar00n_giga"
      - "new goga shooga"
      - "Schnooka_goga"
      - "lorito_r01_gigaFifa"

  tasks:

  - name: Show pattern matching lines
    debug:
      msg: "{{ item }}"
    when: ( item | regex_search('r0[0-9]|goga', ignorecase=True))
    loop: "{{ ITEMS }}"

  - name: Show pattern matching lines
    debug:
      var: item
    when: ( item | regex_search('r0[0-9]|goga', ignorecase=True))
    loop: "{{ ITEMS }}"

  - name: Show pattern matching lines
    debug:
      var: item
    when: ( item | regex_search('r0[0-9]|goga', ignorecase=True))
    with_items:
      - "ar00n_giga"
      - "new goga shooga"
      - "Schnooka_goga"
      - "lorito_r01_gigaFifa"

will result into an output of

TASK [Show pattern matching lines] *************
ok: [localhost] => (item=ar00n_giga) =>
  msg: ar00n_giga
ok: [localhost] => (item=new goga shooga) =>
  msg: new goga shooga
ok: [localhost] => (item=Schnooka_goga) =>
  msg: Schnooka_goga
ok: [localhost] => (item=lorito_r01_gigaFifa) =>
  msg: lorito_r01_gigaFifa

TASK [Show pattern matching lines] *************
ok: [localhost] => (item=ar00n_giga) =>
  ansible_loop_var: item
  item: ar00n_giga
ok: [localhost] => (item=new goga shooga) =>
  ansible_loop_var: item
  item: new goga shooga
ok: [localhost] => (item=Schnooka_goga) =>
  ansible_loop_var: item
  item: Schnooka_goga
ok: [localhost] => (item=lorito_r01_gigaFifa) =>
  ansible_loop_var: item
  item: lorito_r01_gigaFifa

TASK [Show pattern matching lines] *************
ok: [localhost] => (item=ar00n_giga) =>
  ansible_loop_var: item
  item: ar00n_giga
ok: [localhost] => (item=new goga shooga) =>
  ansible_loop_var: item
  item: new goga shooga
ok: [localhost] => (item=Schnooka_goga) =>
  ansible_loop_var: item
  item: Schnooka_goga
ok: [localhost] => (item=lorito_r01_gigaFifa) =>
  ansible_loop_var: item
  item: lorito_r01_gigaFifa

Same result with RHEL 7.9 and Ansible installed from Python Package Index (PyPI)

```bash
ansible --version
...
ansible [core 2.11.12]
...
  python version = 2.7.5 (default, May 30 2023, 03:38:55) [GCC 4.8.5 20150623 (Red Hat 4.8.5-44)]
  jinja version = 2.11.3
  libyaml = True

In short words, I wasn't able to reproduce an error (annot.: constantly).

The error message you are receiving

fatal: [localhost]: FAILED! => {"msg": "template error while templating string: expected token 'end of print statement', got 'goga'. String: {{new goga shooga}}"}

is caused by an incorrect syntax in the debug task, the usage of

var: "{{ item }}"

instead of

var: item

msg: "{{ item }}"