Why are my Ansible handlers not firing? - ansible

Question

I have a playbook that installs tomcat and then deploys some web applications. The web application deploy task(s) notifies a handler to restart tomcat. But the handler never fires. I am using a handler to manage the tomcat service because I understand from the docs that handlers should only fire once even if called multiple times. Am I missing something obvious?
This is the playbook:
---
- hosts: all
become: true
become_user: root
roles:
- role: common
- role: nginx
- role: tomcat
- role: launchpad
- role: manager
- role: reporting
handlers:
- include: /tomcat/handlers/etitomcat_service_ctrl.yml
This is one of the roles that deploys the web app:
---
- name: Remove the current installation of LaunchPad
file: path={{etitomcat_path}}/webapps/{{launchpad_module}} state=absent
- name: Remove the current war file for {{launchpad_module}}
file: path={{etitomcat_path}}/webapps/{{launchpad_module}}.war state=absent
- name: Download the latest snapshot of LaunchPad and deploy it to {{etitomcat_path}}
get_url: url={{launchpad_source_url}} dest={{etitomcat_path}}/webapps/{{launchpad_module}}.war mode=0744 owner={{etitomcat_user}} group={{etitomcat_group}} force=yes
notify: "restart_eti_tomcat"
This is the handler:
- name: "Restart ETI Tomcat"
service: name=etitomcat state=restarted
become: true
become_user: root
listen: "restart_eti_tomcat"
- name: "Start ETI Tomcat"
service: name=etitomcat state=started
become: true
become_user: root
listen: "start_eti_tomcat"
- name: "Stop ETI Tomcat"
service: name=etitomcat state=stopped
become: true
become_user: root
listen: "stop_eti_tomcat"

Answer 1

Adding static: yes should resolve this issue when using Ansible >= 2.1.
handlers:
- include: /tomcat/handlers/etitomcat_service_ctrl.yml
static: yes
Take a look at this Github issue, the linked google groups thread might contain valuable information as well.
edit
As pointed out by #rhythmicdevil the documentation notes:
You cannot notify a handler that is defined inside of an include. As of Ansible 2.1, this does work, however the include must be static.

Answer 2

This may be beside the point but I'll add this regardless as the question headline is rather wide and this is the question I found when googling and below is the solution for the particular issue I had.
Do take into consideration that the handlers only triggers when there is a change registered in the corresponding task. Even if you run the play with the highest verbosity level there will be NO entry like this which spells this out.
RUNNING HANDLER [base : somehandler ] ***********************
Unchanged: Skipping
And when they are triggered after a change it will be after all the tasks has been performed.
This really did my head in since the tasks notified you regardless of if they really did something or not whereas handlers stays quiet.
For example, if you have a task A that you have been running a few times until it works like you expect.
Then after that connect a handler B to restart the service, nothing will happen unless you wipe the operation the task A are doing or change it.
As long as task A registers no change it will not trigger handler B.
This is the behavior for ansible 2.2.1 anyways.

Answer 3

You can add the tasks and post_tasks section instead of handlers, hope it will work for you:
---
- hosts: all
become: true
become_user: root
tasks:
- role: common
- role: nginx
- role: tomcat
- role: launchpad
- role: manager
- role: reporting
post_tasks:
- include: /tomcat/handlers/etitomcat_service_ctrl.yml