---
- hosts: localhost
  tasks:
  - name: Include users.yaml and setup all vars for nexus
    include_vars:
      file: users.yaml
      name: users
  - set_fact:
      tmp_user:
      - username: "{{ item.username }}"
        first_name: "{{ item.first_name }}"
        last_name: "{{ item.last_name }}"
        email: "{{ item.email }}"
        password: "{{ lookup('password', 'credentials/' + item.username + '/password.txt length=15 chars=ascii_letters') }}"
        roles: "{{ item.roles }}"
    loop: "{{ users.nexus_local_users }}"
    register: tmp_users
    when: "not '{{ playbook_dir }}/credentials/{{ item.username }}/password.txt' is exists"
  - set_fact:
      tmp_user: "{{ item.ansible_facts.tmp_user | combine(item.item) }}"
    with_items: "{{ tmp_users.results }}"
    register: tmp_users_sorted
    when: "not item is skipped"
  - set_fact:
      nexus_local_users: "{{ tmp_users_sorted.results | map(attribute='item.ansible_facts.tmp_user') | list | select('defined') | list }}"
  - debug:
      msg: "{{ nexus_local_users }}"

    when: "not '{{ playbook_dir }}/credentials/{{ item.username }}/password.txt' is exists"

    nexus_local_users: "{{ tmp_users_sorted.results | map(attribute='item.ansible_facts.tmp_user') | list | select('defined') | list }}"

   when: "not item is skipped"

    ---
    - hosts: localhost
      tasks:
      - name: Include users.yaml and setup all vars for nexus
        include_vars:
          file: users.yaml
          name: users
      - set_fact:
          tmp_user:
          - username: "{{ item.username }}"
            first_name: "{{ item.first_name }}"
            last_name: "{{ item.last_name }}"
            email: "{{ item.email }}"
            password: "{{ lookup('password', 'credentials/' + item.username + '/password.txt length=15 chars=ascii_letters') }}"
            roles: "{{ item.roles }}"
        loop: "{{ users.nexus_local_users }}"
        register: tmp_users
        when: "not '{{ playbook_dir }}/credentials/{{ item.username }}/password.txt' is exists"
      - set_fact:
          tmp_user: "{{ item.ansible_facts.tmp_user | combine(item.item) }}"
        with_items: "{{ tmp_users.results }}"
        register: tmp_users_sorted
        when: "not item is skipped"
      - set_fact:
          nexus_local_users: "{{ tmp_users_sorted.results | map(attribute='item.ansible_facts.tmp_user') | list | select('defined') | list }}"
      - debug:
          msg: "{{ nexus_local_users }}"

        when: "not '{{ playbook_dir }}/credentials/{{ item.username }}/password.txt' is exists"

        nexus_local_users: "{{ tmp_users_sorted.results | map(attribute='item.ansible_facts.tmp_user') | list | select('defined') | list }}"

       when: "not item is skipped"

I solved this with the Jinja test "exists" and the select filter to filter away the resulting 'AnsibleUndefined' values. The "is exists" test checks if the path exists on the host were the Ansible code is executing on. This is the place the credentials are stored.

The solved code is below:

---
- hosts: localhost
  tasks:
  - name: Include users.yaml and setup all vars for nexus
    include_vars:
      file: users.yaml
      name: users
  - set_fact:
      tmp_user:
      - username: "{{ item.username }}"
        first_name: "{{ item.first_name }}"
        last_name: "{{ item.last_name }}"
        email: "{{ item.email }}"
        password: "{{ lookup('password', 'credentials/' + item.username + '/password.txt length=15 chars=ascii_letters') }}"
        roles: "{{ item.roles }}"
    loop: "{{ users.nexus_local_users }}"
    register: tmp_users
    when: "not '{{ playbook_dir }}/credentials/{{ item.username }}/password.txt' is exists"
  - set_fact:
      tmp_user: "{{ item.item | combine(item.item) }}"
    with_items: "{{ tmp_users.results }}"
    register: tmp_users
    when: "not item is skipped"
  - set_fact:
      nexus_local_users: "{{ tmp_users.results | map(attribute='ansible_facts.tmp_user') | list | select('defined') | list }}"
  - debug:
      msg: "{{ nexus_local_users }}"

The following was added/changed:

    when: "not '{{ playbook_dir }}/credentials/{{ item.username }}/password.txt' is exists"

      nexus_local_users: "{{ tmp_users.results | map(attribute='ansible_facts.tmp_user') | list | select('defined') | list }}"

This makes for a compact solution without adding more tasks/files.

For more information see: https://docs.ansible.com/ansible/latest/user_guide/playbooks_tests.html

I solved this with the Jinja test "exists" and the select filter to filter away the resulting 'AnsibleUndefined' values. The "is exists" test checks if the path exists on the ansible control host. This is the place the credentials are stored.

The solved code is below:

---
- hosts: localhost
  tasks:
  - name: Include users.yaml and setup all vars for nexus
    include_vars:
      file: users.yaml
      name: users
  - set_fact:
      tmp_user:
      - username: "{{ item.username }}"
        first_name: "{{ item.first_name }}"
        last_name: "{{ item.last_name }}"
        email: "{{ item.email }}"
        password: "{{ lookup('password', 'credentials/' + item.username + '/password.txt length=15 chars=ascii_letters') }}"
        roles: "{{ item.roles }}"
    loop: "{{ users.nexus_local_users }}"
    register: tmp_users
    when: "not '{{ playbook_dir }}/credentials/{{ item.username }}/password.txt' is exists"
  - set_fact:
      tmp_user: "{{ item.ansible_facts.tmp_user | combine(item.item) }}"
    with_items: "{{ tmp_users.results }}"
    register: tmp_users_sorted
    when: "not item is skipped"
  - set_fact:
      nexus_local_users: "{{ tmp_users_sorted.results | map(attribute='item.ansible_facts.tmp_user') | list | select('defined') | list }}"
  - debug:
      msg: "{{ nexus_local_users }}"

The following was added/changed:

    when: "not '{{ playbook_dir }}/credentials/{{ item.username }}/password.txt' is exists"

    nexus_local_users: "{{ tmp_users_sorted.results | map(attribute='item.ansible_facts.tmp_user') | list | select('defined') | list }}"

   when: "not item is skipped"

This makes for a compact solution without adding more tasks/files.

For more information see: https://docs.ansible.com/ansible/latest/user_guide/playbooks_tests.html