Conditionally add additional arguments to command module with Ansible

Question

I have a task in an ansible role which calls a script with a bunch of args that are defined as ansible variables. The task looks like this:

- name: Generate config files
  command: /etc/whatever/gen-config.sh -n {{domain}} -m {{ another_option }} -w {{ws_enabled | default('N') }} -r {{ last_one_optional}}

The problem is that the -r is an optional argument, so sometimes I don't have an ansible variable to pass to it, and the script complained if I used a default("") instead. Is there some way to optionally include the -r only if {{last_one_optional}} is defined? I have seen some of the jinja inline if statements and I didn't know if that would work for ansible or not.

Answer 1

Use conditional:

{{ ('-r ' + last_one_optional) if last_one_optional is defined else '' }}