Ansible regex_findall is not giving expected results with negative search - ansible

Question

My ansible negative regex is returning everything
So I'm getting results of dns names from JSON, of which I'm trying to sort to create an automated ansible inventory.
I have servers with naming schemes such as:
abc02vsomeserver01.subdomain1.domain.gov
abc02someserver01.subdomain1.domain.gov
xyz03votherserver11.subdomain2.domain.gov
wyz03otherserver11.subdomain2.domain.gov
qrsmainserver02.maindomain.domain.gov
I'm getting the "v" servers divided out by environment, then I want to create a catchall group that is not the "v" servers
So! I'm attempting to do:
{{ jsonOutput | json_query('json.response.results[].dnsName') | regex_findall('(?![a-z]{3}[0-9]{2}v)^.*', multiline=true) }}
Which does seem to work when I plug it into https://pythex.org.
But ansible is returning everything instead...
What the heck am I doing wrong here?

Answer 1

It's because that json_query emits a list[str] which when fed directly into regex_findall doesn't become a newline delimited string, it becomes the same as str(["alpha", "beta"]) (e.g. ['alpha', 'beta']) and then the multiline regex fails to do what you are expecting
There are, as with many things in life, a few ways to fix that. One is to just feed the results into |join("\n") and then you're likely back where you thought you were to begin with:
- debug:
msg: "{{ jsonOutput | json_query('json.response.results[].dnsName') | join('\n') | regex_findall('(?![a-z]{3}[0-9]{2}v)^.*', multiline=true) }}"
The other is to acknowledge that it's a list[str] and use the | select("match", ...) filter to only allow though items that match:
- debug:
msg: >-
{{ response | json_query('results[].dnsName')
| select('match', '(?![a-z]{3}[0-9]{2}v)^.*')
| list }}
vars:
response:
results:
- dnsName: abc02vsomeserver01.subdomain1.domain.gov
- dnsName: abc02someserver01.subdomain1.domain.gov
- dnsName: xyz03votherserver11.subdomain2.domain.gov
- dnsName: wyz03otherserver11.subdomain2.domain.gov
- dnsName: qrsmainserver02.maindomain.domain.gov
similarly produces:
"msg": [
"abc02someserver01.subdomain1.domain.gov",
"wyz03otherserver11.subdomain2.domain.gov",
"qrsmainserver02.maindomain.domain.gov"
]
I would guess it's personal preference which style works best in your playbook