ansible.builtin.generator – Uses Jinja2 to construct hosts and groups from patterns

Note

This module is part of ansible-base and included in all Ansible installations. In most cases, you can use the short module name generator even without specifying the collections: keyword. Despite that, we recommend you use the FQCN for easy linking to the module documentation and to avoid conflicting with other collections that may have the same module name.

New in version 2.6: of ansible.builtin

Synopsis

• Uses a YAML configuration file with a valid YAML or .config extension to define var expressions and group conditionals

• Create a template pattern that describes each host, and then use independent configuration layers

• Every element of every layer is combined to create a host for every layer combination

• Parent groups can be defined with reference to hosts and other groups using the same template variables

Parameters

Parameter	Choices/Defaults	Configuration	Comments
hosts string			The name key is a template used to generate hostnames based on the layers option. Each variable in the name is expanded to create a cartesian product of all possible layer combinations. The parents are a list of parent groups that the host belongs to. Each parent item contains a name key, again expanded from the template, and an optional parents key that lists its parents. Parents can also contain vars, which is a dictionary of vars that is then always set for that variable. This can provide easy access to the group name. E.g set an application variable that is set to the value of the application layer name.
layers string			A dictionary of layers, with the key being the layer name, used as a variable name in the host name and parents keys. Each layer value is a list of possible values for that layer.
plugin string / required	Choices: generator		token that ensures this is a source file for the 'generator' plugin.

Examples

# inventory.config file in YAML format
# remember to enable this inventory plugin in the ansible.cfg before using
# View the output using `ansible-inventory -i inventory.config --list`
plugin: generator
hosts:
    name: "{{ operation }}_{{ application }}_{{ environment }}_runner"
    parents:
      - name: "{{ operation }}_{{ application }}_{{ environment }}"
        parents:
          - name: "{{ operation }}_{{ application }}"
            parents:
              - name: "{{ operation }}"
              - name: "{{ application }}"
          - name: "{{ application }}_{{ environment }}"
            parents:
              - name: "{{ application }}"
                vars:
                  application: "{{ application }}"
              - name: "{{ environment }}"
                vars:
                  environment: "{{ environment }}"
      - name: runner
layers:
    operation:
        - build
        - launch
    environment:
        - dev
        - test
        - prod
    application:
        - web
        - api