Ansible: How to do a loop to call series of handler tasks?

Question

I'm quite new to ansible and I have been working on writing an ansible role to automate the incremental upgrade process for Jenkins. Part of this process has involved creating a loop which executes on the condition that the current version of Jenkins installed on the instance is older than the target version.

# Install the incremental upgraded version of Jenkins
- name: upgrade and restart jenkins on each iterative upgrade
  yum:
    name: "jenkins-{{ item.jenkins_target_version }}"
    state: present
  when: (jenkins_current_version | float) < "{{ item.jenkins_target_version_filtered }}"
  loop: "{{ packages }}"
  notify: restart jenkins
  when: (jenkins_current_version | float) < jenkins_target_filtered

The loop should cycle through the list of packages which looks like this

packages:
  - { jenkins_target_version: 2.176-1.1, jenkins_target_version_filtered: 2.176 }
  - { jenkins_target_version: 2.190-1.1, jenkins_target_version_filtered: 2.190 }
  - { jenkins_target_version: 2.204-1.1, jenkins_target_version_filtered: 2.204 }
  - { jenkins_target_version: 2.222-1.1, jenkins_target_version_filtered: 2.222 }
  - { jenkins_target_version: 2.235-1.1, jenkins_target_version_filtered: 2.235 }
  - { jenkins_target_version: 2.249-1.1, jenkins_target_version_filtered: 2.249 }
  - { jenkins_target_version: 2.263-1.1, jenkins_target_version_filtered: 2.263 }
  - { jenkins_target_version: 2.277-1.1, jenkins_target_version_filtered: 2.277 }
  - { jenkins_target_version: 2.289-1.1, jenkins_target_version_filtered: 2.289 }
  - { jenkins_target_version: 2.303-1.1, jenkins_target_version_filtered: 2.303 }
  - { jenkins_target_version: 2.319-1.1, jenkins_target_version_filtered: 2.319 }
  - { jenkins_target_version: 2.332-1.1, jenkins_target_version_filtered: 2.332 }
  - { jenkins_target_version: 2.343-1.1, jenkins_target_version_filtered: 2.343 }
  - { jenkins_target_version: 2.346-1.1, jenkins_target_version_filtered: 2.346 }

And only install the version on the target system if it is a newer iteration than what is currently installed. The loop seems to work correctly and installs the upgrade of jenkins on the target instance, the problem is that I want to execute a series of handler tasks whenever jenkins has been upgraded.

The handlers are a series of tasks stored in a file in the handlers folder that restart the service and check that things are back up and running ok (among other things). The problem is that the handler tasks are not called and executed upon completion of each iterative upgrade. I'm looking for advice on how I can make this happen, thanks in advance.

Answer 1

Q: "I want to execute a series of handler tasks."

A: Use the keyword listen to select more tasks. For example, given the handlers

shell> cat handlers/restart_jenkins.yml
- debug:
    msg: Restart service
  listen: restart jenkins

- debug:
    msg: Check that things are back up and running ok
  listen: restart jenkins

- debug:
    msg: |-
      Do whatever you want next
      {{ out.results|json_query('[].stdout') }}
  listen: restart jenkins

The playbook

- hosts: test_11
  gather_facts: false
  vars:
    packages:
      - {target: 2.176-1.1, current: 2.176}
      - {target: 2.190-1.1, current: 2.190}
      - {target: 2.204-1.1, current: 2.205}
  tasks:
    - command: "echo install {{ item.target }}"
      register: out
      notify: restart jenkins
      loop: "{{ packages }}"
      when: item.current is version(item.target, "<")
    - meta: flush_handlers
    - debug:
        msg: Continue ...
  handlers:
    - import_tasks: handlers/restart_jenkins.yml

gives

PLAY [test_11] *******************************************************************************

TASK [command] *******************************************************************************
changed: [test_11] => (item={'target': '2.176-1.1', 'current': 2.176})
changed: [test_11] => (item={'target': '2.190-1.1', 'current': 2.19})
skipping: [test_11] => (item={'target': '2.204-1.1', 'current': 2.205}) 

TASK [meta] **********************************************************************************

RUNNING HANDLER [debug] **********************************************************************
ok: [test_11] => 
  msg: Restart service

RUNNING HANDLER [debug] **********************************************************************
ok: [test_11] => 
  msg: Check that things are back up and running ok

RUNNING HANDLER [debug] **********************************************************************
ok: [test_11] => 
  msg: |-
    Do whatever you want next
    ['install 2.176-1.1', 'install 2.190-1.1']

TASK [debug] *********************************************************************************
ok: [test_11] => 
  msg: Continue ...

PLAY RECAP ***********************************************************************************
test_11                    : ok=5    changed=1    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0

Notes:

• The use case of installing new versions in a loop doesn't make sense. The play here serves the only purpose of demonstrating the functionality of handlers.
• Flush the handlers if you don't want to wait till the end of the playbook.