Check to see if an Ansible Prompt Variable exists - if-statement

Question

In my site.yml, I run some common tasks, then include 3 other playbooks.
These 3 playbooks then run a role each.
I do this so I can run a full site.yml install, or I can just run a smaller playbook.
I want to prompt for a username and password in the site.yml, which I can do.
Then in the other 3 playbooks/roles, I want to check if the username and password were already created, if not, then prompt for them.
I do not want to prompt for credentials multiple times.
site.yml
---
- hosts: all
vars_prompt:
- name: "username"
- prompt" "enter username"
- include: 1.yml
1.yml
---
- name: install one
hosts: all
# If username has not been defined - This is
# where I am confused how to check if it was defined in site.yml
vars_prompt:
- name: "userame"
prompt: "enter username"
roles:
- 1role
If I run site.yml, it will get username, then run 1.yml and I don't want it to prompt for username because it was prompted for in site.yml.
If I run just 1.yml, I want it to prompt for the username, as I am not running site.yml in this case.
Is there a way to prompt for credentials from a playbook, then check for them in an included playbook?

Answer 1

You should make a file that ansible writes on host and ansible could then check whether those credentials have been filled in or not yet, or you could use register (probably the best option) and then use when to check (when is like an if statement)
For instance:
site.yml
- name: "username"
- prompt" "enter username"
register: username_check
1.yml
- name: "userame"
prompt: "enter username"
when: username_check is not defined
I hope this helps in some regard. I tried to comment but it wouldn't let me.