Ansible - Check if string exists in file with regex - regex

Question

I need to validate that the PermitRootLogin parameter is equal to "no", for example:
PermitRootLogin no
But sometimes between these words there is more than one space. For this reason I use a regex, but apparently I do it wrong. This is the line that seems to be bad:
when: check_config.stdout.find('PermitRootLogin\s+no') != -1
Any idea how to fix this?
- hosts: redhat
tasks:
- name: check file
shell: cat /etc/ssh/sshd_config
register: check_config
- name: compare string
when: check_config.stdout.find('PermitRootLogin\s+no') != -1
debug: msg="this server is ok"

Answer 1

Q: "Validate that the PermitRootLogin parameter is equal to no."
A: Put the below declaration into the vars
match_lines: "{{ check_config.stdout_lines|
map('regex_search', '^\\s*PermitRootLogin\\s+no$')|
select }}"
and test the length of the list
- debug:
msg: this server is OK
when: match_lines|length > 0
Example of a complete playbook for testing
- hosts: localhost
vars:
match_lines: "{{ check_config.stdout_lines|
map('regex_search', '^\\s*PermitRootLogin\\s+no$')|
select }}"
tasks:
- command: cat /etc/ssh/sshd_config
register: check_config
- debug:
var: match_lines
- debug:
msg: This server is OK
when: match_lines|length > 0
gives, for example (abridged)
TASK [debug] *******************************************
ok: [localhost] =>
match_lines:
- PermitRootLogin no
TASK [debug] *******************************************
ok: [localhost] =>
msg: This server is OK
Given the inventory below set hosts -hosts: rehat
shell> cat hosts
[redhat]
test_11
test_12
test_13
The playbook gives, for example (abridged)
TASK [debug] *******************************************
ok: [test_11] =>
match_lines:
- PermitRootLogin no
ok: [test_12] =>
match_lines: []
ok: [test_13] =>
match_lines: []
TASK [debug] *******************************************
skipping: [test_12]
ok: [test_11] =>
msg: This server is OK
skipping: [test_13]
You can use lookup to simplify the task if the play is running at the localhost only. For example, the playbook below gives the same result
- hosts: localhost
tasks:
- debug:
msg: This server is OK
when: match_lines|length > 0
vars:
match_lines: "{{ lookup('file', '/etc/ssh/sshd_config').splitlines()|
map('regex_search', '^\\s*PermitRootLogin\\s+no$')|
select }}"
If you want to put/replace the line in the config use lineinfile. For example,
- lineinfile:
path: /etc/ssh/sshd_config
regexp: '^PermitRootLogin(.*)$'
line: 'PermitRootLogin no'