How to escape 1 or more whitespaces in a regex in the lineinfile module of Ansible?

Question

I am using Ansible to set some variables on a file using the lineinfile module. The problem I'm bumping into is how to have a regular expression that is flexible enough to have some spaces in the middle of the string. Please see below:

- name: Set DB IP in db conn file
  lineinfile: 
    dest=/path/to/db_conn
    regexp="{{ item.regexp }}"
    line="{{ item.line }}"
  with_items:
    - { regexp: "^.?dbschema_audit=",
        line: "$dbschema_audit=\'{{ db_schema_audit }}\';" }
    - { regexp: "^.?dbschema_audit_trail\s\*=",
        line: "$dbschema_audit_trail=\'{{ db_schema_audit_trail }}\';" }

The file I'm trying to change has lines like these:

$dbschema_audit='a';
$dbschema_audit_trail ='a';

I have tried different variations of \s* with {, ' and \ and nothing seems to work. Can I have some wisdom from out there?

Answer 1

Ansible playbooks are in YAML format. In a double quoted scalar, character sequences starting with the \ character are escape sequences, but the YAML specification says \s is a not a valid escape sequence.

In a double quoted scalar, you would have to write

"\\s"

Alternatively, in a single quoted scalar, the \ character has no special meaning, so you can write

'\s'