在回调插件中使用“ set_fact”获取事实集的值

Question

Ansible 2.3

I have a callback plugin which notifies an external service when a playbook is finished. During the play, this callback plugin collects different information like the play variables and error messages, which is sent with the HTTP request. Example:

{
    "status": 1, 
    "activity": 270,
    "error": "Task xyz failed with message: failure message",
    "files": [ "a.txt", "b.cfg" ]
}

Some of this information comes from variables set during the play itself, it could be anything relevant for that play: the path to a file, a list of changed resources, etc.

Right now I'm doing something particularly ugly to collect what I need based on task names:

def v2_runner_on_ok(self, result):

    if result._task.action == 'archive':
        if result._task.name == 'Create archive foo':
            self.body['path'] = result._result['path']

    if result._task.action == 'ec2':
        if result._task.name == 'Start instance bar':
            self.body['ec2_id'] = result._result['id']

   # do it for every task which generates "interesting" info

Obviously this doesn't scale and breaks if the task name changes.

To keep it generic I've been thinking about agreeing on a fact name, say add_to_body , which would be added to the body dictionary whenever it exists. I like this approach because it's particularly easy to register a couple of variables during the play and use them to assemble a fact at the end of a play. Example:

---

- name: Demo play
  hosts: localhost
  gather_facts: False

  tasks:

    - name: Create temporary file 1
      tempfile:
        path: '/tmp'
      register: reg_tmp_1

    - name: Create temporary file 2
      tempfile:
        path: '/tmp'
      register: reg_tmp_2

    - name: Set add_to_body fact
      set_fact:
        add_to_body: "{{ { 'reg_tmp_1': reg_tmp_1.path,
                           'reg_tmp_2': reg_tmp_2.path } }}"

    - debug: var=add_to_body

However I can't find a way to access the value of a fact after a set_fact action, neither by looking at the result object nor by trying to access the hostvars for the current host (which is apparently not possible inside a callback plugin ).

What would you suggest to work around this limitation?

Answer 1

Hmm, you mix some things in here.
If you want to call API in v2_runner_on_ok after each task, you should handle add_to_body in task context.
But in your example you set add_to_body after several tasks – this way you'd better write action plugin (eg send_to_my_service ) and call it instead of set_fact with required parameters.

Here's example how you can use add_to_body in task context:

---
- hosts: localhost
  gather_facts: no

  tasks:
    - command: echo hello world
      vars:
        add_to_body:
          - path
    - file:
        dest: /tmp/zzz
        state: touch
      vars:
        add_to_body:
          - dest

Callback:

def v2_runner_on_ok(self, result):
    if 'add_to_body' in result._task.vars:
        res = dict()
        for i in result._task.vars['add_to_body']:
            if i in result._result:
                res[i] = result._result[i]
            else:
                display.warning('add_to_body: asked to add "{}", but property not found'.format(i))
        display.v(res)