ansible: pass variable to a handler

Question

I use an "eye" as a supervisor and on changes in templates have to runs something like this:

eye load service.rb
eye restart service.rb

I want to define this as a single handler for all the apps and call it like

eye reload appname

And in a handler operate like this:

- name: reload eye service
command: eye load /path/{{ service }}.rb && eye restart {{ service }}

But I can't find a way to pass variable to a handler. Is it possible?

Answer 1

Don't do this. I understand your desire to use Ansible as a programming tool, where 'handler' is a 'function' you 'call', but it's not.

You can invent a dozen of tricks to do what you want, but result would be a total mess, hard to read and even harder to debug.

The key issue is that ansible does not support 'argument passing' to anything (except for modules). All tricks you read about or invent by yourself will change global variable. If you ever wrote at least bit in any language , you know, that program where every function is using global variables (for read and write, and to pass arguments) is fundamentally flawed.

So, how to do this in a very good and readable Ansible?

Yes, just wrote a separate handler for each service. It's the cleanest and simplest Ansible. Easy to read, easy to change.

BTW: if you have to actions in a chain, do not join them with '&&'.

Use two separate handlers:

- foo:
  notify:
    - eye reload
    - eye restart foo

(note, that order of handlers is defined in the handlers list, not the 'notify' list).

Btw, if you have few services you will save on multiple reload operations - 'eye reload' would be called once.