Send one email with vars from a large play

sendmail.yml

- name: Generate log file name
  hosts: all
  connection: local
  tasks:
    - shell: mktemp
      register: mktemp
      always_run: yes
      run_once: true

- name: Write entries to the log file
  hosts: outdated
  connection: local
  serial: 1
  tasks:
    - lineinfile: dest={{ mktemp.stdout }} line="Host {{ inventory_hostname }} was updated at {{ ansible_date_time.date }} {{ ansible_date_time.time }} {{ ansible_date_time.tz }}" create=no state=present
      always_run: yes
    

- name: Send email with update log
  hosts: outdated
  connection: local
  tasks:
    - stat: path={{ mktemp.stdout }}
      register: updatelogcheck
      always_run: yes
      run_once: yes
    - shell: cat {{ mktemp.stdout }}
      register: mail_body
      when: updatelogcheck.stat.exists == true
      always_run: yes
      run_once: yes
      mail: subject='Update completed' body='{{ mail_body.stdout }}' from='you@yourdomain.com (Your Name)' to='Recipient <some@recipient.com>' cc='Other Recipient <other@recipient.com>'
      when: updatelogcheck.stat.exists == true and mail_body.stdout != ""
      run_once: yes
    - file: path={{ mktemp.stdout }} state=absent
      always_run: yes
      run_once: yes