Ansible: get all variables in own module?

Question

Now I use my own module this way:

- get_my_data:
    hostvars: '{{ hostvars }}'

It uses configuration for all hosts and collects some data.
Can I get hostvars inside this module without explicit actions?

module = AnsibleModule(
    argument_spec=dict(
        hostvars=dict(type='dict', required=True),
    ),
    supports_check_mode=True
)
hostvars = module.params['hostvars']
# some exports
result = {'changed': False, 'ansible_facts': {'my_data': 'test'}}
module.exit_json(**result)

Also I export new variables using ansible_facts dictionary. How can I export them via register ?

Update: Jinja {{ variables }} are not replaced inside hostvars dict. How can I fix it to give actual vars to module?

Update 2:
hostvars: '{{ hostvars | to_json }}' hostvars: '{{ hostvars | to_json }}' helped me to evaluate all the variables

Ansible 2.7.1

Answer 1

Can I get hostvars inside this module without explicit actions?

No. You need to explicitly pass in any variables to which you want the module to have access.

How can I export them via register?

Anything returned via the exit_json method will be available in your registered variable. That is, if you were to have...

result = {'changed': False, 'my_data': 'test'}
module.exit_json(**result)

...you would find a my_data key in your registered variable.

Jinja {{ variables }} are not replaced inside hostvars dict. How can I fix it to give actual vars to module?

I don't think you're going to be able to do that within your module. With a more complete example in your question, showing exactly what you're trying to do, we might be able to suggest alternative ways of approaching the problem.