includes in ansible

magic.yml

---
- debug:
    msg: "magic"
...

more_magic.yml

---
- debug:
    msg: "more magic"
...

test.md

without "do_magic"

$ ansible-playbook test.yml -vv
Using /path/to/.ansible.cfg as config file
statically included: /path/to/more_magic.yml

PLAYBOOK: test.yml *************************************************************
1 plays in test.yml

PLAY [localhost] ***************************************************************
META: ran handlers

TASK [debug] *******************************************************************
task path: /path/to/more_magic.yml:2
skipping: [localhost] => {"changed": false, "skip_reason": "Conditional result was False", "skipped": true}

TASK [with_items include all magic] ********************************************
task path: /path/to/test.yml:23
skipping: [localhost] => (item=magic.yml)  => {"changed": false, "item": "magic.yml", "skip_reason": "Conditional result was False", "skipped": true}
skipping: [localhost] => (item=more_magic.yml)  => {"changed": false, "item": "more_magic.yml", "skip_reason": "Conditional result was False", "skipped": true}

TASK [with_first_found include magic] ******************************************
task path: /path/to/test.yml:33
skipping: [localhost] => (item=/path/to/magic.yml)  => {"changed": false, "item": "/path/to/magic.yml", "skip_reason": "Conditional result was False", "skipped": true}

TASK [with_first_found include magic] ******************************************
task path: /path/to/test.yml:43

TASK [some magic include] ******************************************************
task path: /path/to/test.yml:54
skipping: [localhost] => {"changed": false, "skip_reason": "Conditional result was False", "skipped": true}
META: ran handlers
META: ran handlers

PLAY RECAP *********************************************************************
localhost                  : ok=0    changed=0    unreachable=0    failed=0  

with "do_magic"

$ ansible-playbook test.yml -e "do_magic" -vv
Using /path/to/.ansible.cfg as config file
statically included: /path/to/more_magic.yml

PLAYBOOK: test.yml *************************************************************
1 plays in test.yml

PLAY [localhost] ***************************************************************
META: ran handlers

TASK [debug] *******************************************************************
task path: /path/to/more_magic.yml:2
skipping: [localhost] => {"changed": false, "skip_reason": "Conditional result was False", "skipped": true}

TASK [with_items include all magic] ********************************************
task path: /path/to/test.yml:23
skipping: [localhost] => (item=magic.yml)  => {"changed": false, "item": "magic.yml", "skip_reason": "Conditional result was False", "skipped": true}
skipping: [localhost] => (item=more_magic.yml)  => {"changed": false, "item": "more_magic.yml", "skip_reason": "Conditional result was False", "skipped": true}

TASK [with_first_found include magic] ******************************************
task path: /path/to/test.yml:33
skipping: [localhost] => (item=/path/to/magic.yml)  => {"changed": false, "item": "/path/to/magic.yml", "skip_reason": "Conditional result was False", "skipped": true}

TASK [with_first_found include magic] ******************************************
task path: /path/to/test.yml:43

TASK [some magic include] ******************************************************
task path: /path/to/test.yml:54
skipping: [localhost] => {"changed": false, "skip_reason": "Conditional result was False", "skipped": true}
META: ran handlers
META: ran handlers

PLAY RECAP *********************************************************************
localhost                  : ok=0    changed=0    unreachable=0    failed=0

test.yml

---
## Ansible 2.3.2.0
- hosts: localhost
  gather_facts: "False"
  tasks:

  ## Common include
  
  # This will evaluate(?) the tasks in more_magic.yml
  # even if "do_magic" is not defined
  # This is because by default "static" is "yes"
  # and all children inherit the conditional "when" clause
  - name: some magic include
    include: more_magic.yml
    when: do_magic is defined
  
  
  ## Include using "with_" clauses
  
  # "with_items" will behave as setting static: no.
  # This task will include all the files in "with_items"
  # Evaluating all the child tasks in the files, only when "do_magic" is defined
  - name: with_items include all magic
    include: "{{ item }}"
    with_items:
      - magic.yml
      - more_magic.yml
    when: do_magic is defined
  
  # "with_first_found" will behave as setting static: no.
  # This taks will include the first file found from the list.
  # Evaluating the children only when the do_magic is defined
  - name: with_first_found include magic
    include: "{{ item }}"
    with_first_found:
      - magic.yml
      - more_magic.yml
    when: do_magic is defined
  
  
  # If a file is not found this can be used, see the difference in formatting
  # compared to the previous one, also note the "skip" attribute which avoids failure
  - name: with_first_found include magic
    include: "{{ item }}"
    with_first_found:
      - skip: "true"
        files:
          - no_magic.yml
    when: do_magic is defined
  
  
  # This one will not evaluate the child tasks when "do_magic" is not defined
  # as we are explicily setting  static: "no"
  - name: some magic include
    include: more_magic.yml
    static: no
    when: do_magic is defined
...