Schemas for Ansible and its related tools

About Schemas

This project aims to generate JSON/YAML validation schemas for Ansible files such as playbooks, tasks, requirements, meta or vars and also for Molecule configuration.

Keep in mind that these schemas will limit your freedom of choice regarding the syntax you can use to write Ansible tasks as they do not allow some historical forms which are still allowed by Ansible itself.

Not any file accepted by Ansible will pass these schemas but we do expect that any file that passed these schemas should be accepted by Ansible.

• YAML 1.2 booleans are required as true or false, while Ansible itself allows you to use more relaxed forms like yes or no.
• Inline actions are not allowed, as schema cannot validate them
• Non-built-in modules must be called using action: blocks
• Module arguments are not yet verified but we plan to implement it
• Out schemas are strict about usage of jinja2 templating and require {{ on arguments declared as explicit, which forbid the use of {{ on those marked as implicit. See the section below for details.

As these schemas are still experimental, creating pull requests to improve the schema is of much greater help. Though you are still welcome to report bugs but expect them to take a long time until someone finds time to fix them.

If you want to help improve the schemas, have a look at the development documentation.

Schema Bundle

We are currently migrating towards a single ansible.json schema bundle, one that contains subschema definitions for all the supported file types.

To configure your validator or editor to use the bundle, use the new URLs below, the part after the # in the URLs is essential for informing the loader about which subschema to use. You can also look at our settings.json to understand how to configure the vscode-yaml extension.

• playbook subschema url
• tasks subschema uri

Jinja2 implicit vs explicit templating

While Ansible might allow you to combine implicit and explicit templating, our schema will not. Our schemas will only allow you to use the recommended form, either by forbidding you to use the curly braces on implicit ones or forcing you to add them on explicit ones.

Examples:

- name: some task
  command: echo 123
  register: result
  vars:
    become_method_var: sudo
  become_method: become_method_var # <-- schema will not allow this
  # become_method: "{{ become_method_var }}" # <-- that is allowed

How to find if a field is implicit or explicit?

Run assuming that your keyword is no_log, you can run ansible-doc -t keyword no_log, which will give you the following output:

failed_when:
  applies_to:
    - Task
  description:
    Conditional expression that overrides the task's normal 'failed' status.
  priority: 0
  template: implicit
  type: list

As you can see the template field tells you if is implicit or explicit.

Being more restrictive, schema protects you from common accidents, like writing a simple string in an explicit field. That will always evaluate as true instead of being evaluated as a jinja template.

Activating the schemas

At this moment installing Ansible VS Code Extension by Red Hat will activate these schemas. The file patterns used to trigger their use can be seen here

Because these schemas are generic, you can easily use them with any validators that support them.