Module format and documentation

In most cases if you want to contribute your module to an Ansible collection, you should write your module in Python and follow the standard format described below. If you are writing a Windows module, you should follow the Windows guidelines.

Before you open a pull request, in addition to following these guidelines, please also review and adhere to the practices outlined in the following sections:

Every Ansible module written in Python must begin with seven standard sections in a particular order, followed by the code. The sections in order are:

If you are curious why imports are not located at the top of the file, see the Python imports section.

If you see any discrepancies in older Ansible modules, please open a pull request with modifications that satisfy these guidelines.

Non-Python modules documentation

For modules written in languages other than Python, there are two approaches to handling documentation:

  • Option one: Create a .py file that contains the documentation-related sections described in this document.

  • Option two: Create a .yml file that has the same data structure in pure YAML.

    • With YAML files, the examples below are easy to use by removing Python quoting and substituting = for :, for example DOCUMENTATION = r''' ... ''' to DOCUMENTATION: ... and removing closing quotes. Refer to Adjacent YAML documentation files for details.

Python shebang & UTF-8 coding

  1. Begin your Ansible module with the #!/usr/bin/python shebang so that ansible_python_interpreter works.

  • If you develop the module using a different scripting language, adjust the interpreter accordingly (#!/usr/bin/<interpreter>) so ansible_<interpreter>_interpreter can work for that specific language.

  • Binary modules do NOT require a shebang or an interpreter.

  • Do NOT use #!/usr/bin/env because it makes env the interpreter and bypasses ansible_<interpreter>_interpreter logic.

  • Passing arguments to the interpreter in the shebang does not work; for example, #!/usr/bin/env python.

  1. Follow the shebang immediately with # -*- coding: utf-8 -*- to clarify that the file is UTF-8 encoded.

DOCUMENTATION block

Before committing your module documentation, please test it at the command line and as HTML.

After the shebang, the UTF-8 encoding, the copyright line, and the license section comes the DOCUMENTATION block. Ansible’s online module documentation is generated from the DOCUMENTATION blocks in the source code of each module.

The DOCUMENTATION block must be valid YAML. To make it easier:

When writing module documentation, take the following statements into consideration:

  • Module documentation should briefly and accurately define what each module and option does and how it works with others in the underlying system.

  • Module documentation should be written for a broad audience and be easily understood both by experts and non-experts.

  • Descriptions should always start with a capital letter and end with a full stop or period. Consistency always helps.

  • For password and secret arguments no_log=True should be set and any example passwords, secrets, or hashes should start with EXAMPLE to ensure no real passwords and so on are leaked.

  • For arguments that seem to contain sensitive information but do not contain secrets, such as “password_length”, set no_log=False to disable the warning message.

  • If an option is only required in certain conditions, describe those conditions; for example, “Required when I(state=present).”

  • If your module allows check_mode, reflect this fact in the documentation.

  • To create clear, concise, consistent, and useful documentation, follow the style guide.

Each documentation field is described below.

Documentation fields

  • All fields in the DOCUMENTATION block are lower-case.

  • All fields are required unless specified otherwise.

module:

  • The name of the module.

  • Must be the same as the file name, without the .py extension.

short_description:

  • A short description which is displayed on the Collection Index page and ansible-doc -l.

  • The short_description is displayed by ansible-doc -l without any category grouping, so it needs enough detail to explain the module’s purpose without the context of the directory structure in which it lives.

  • Unlike description:, short_description MUST NOT have a trailing period/full stop.

  • You can use Ansible markup in this field.

description:

  • A detailed description (generally two or more sentences).

  • Each sentence MUST be full: start with a capital letter and end with a period.

  • SHOULD NOT mention the module name.

  • Make use of multiple entries rather than using one long paragraph.

  • MUST NOT quote complete values unless it is required by YAML.

  • You can use Ansible markup in this field.

version_added:

  • This is a string, not a float, and should be quoted to avoid errors.

  • For ansible.builtin.* modules (included in ansible-core), it is a version of ansible-core, for example, version_added: '2.18'

  • In collections, it MUST be a version of a collection (not the Ansible version) when the module was added, for example, version_added: '1.0.0'.

author:

  • Name of the module author in the form First Last (@GitHubID).

  • Use a multi-line list if there is more than one author.

  • Do NOT use quotes unless it is required by YAML.

deprecated:
options:

  • Options are often called “parameters” or “arguments”. Because the documentation field is called options, we will use that term.

  • If the module has no options (for example, it is a _facts module), all you need is one line: options: {}.

  • If your module has options (in other words, accepts arguments), document them thoroughly. For each module option, include:

option-name:

  • Name it as a declarative operation (not CRUD) that focuses on the final state, for example online:, rather than is_online:.

  • Make the name consistent with the rest of the module, as well as other modules in the same category.

  • When in doubt, look for other modules to find option names that are used for the same purpose, we like to offer consistency to our users.

  • There is no explicit field option-name. This entry is about the key of the option in the options dictionary.

description:

  • Detailed explanation of what this option does. Write it in full sentences that shart with a capital letter and end with a period.

  • The first entry is a description of the option itself; subsequent entries detail its use, dependencies, or format of possible values.

  • Do NOT list the possible values (that’s what the choices: field is for, though it should explain what the values do if they are not obvious).

  • If an option is only sometimes required, describe the conditions. For example, “Required when O(state=present).”

  • Mutually exclusive options MUST be documented as the final sentence on each of the options.

  • You can use Ansible markup in this field.

required:

  • Only needed if true.

  • If missing, we assume the option is not required.

default:

  • If required is either false or missing, default may be specified (assumed null if missing).

  • Ensure that the default value in the docs matches the default value in the code.

  • The default field MUST NOT be listed as part of the description, unless it requires additional information or conditions.

  • If the option is a boolean value, you can use any of the boolean values recognized by Ansible (such as true/false or yes/no). Document booleans as true/false for consistency and compatibility with ansible-lint.

choices:

  • List of option values.

  • Do NOT use it if empty.

type:

  • Specifies the data type that option accepts, MUST match the argument_spec dictionary.

  • If an argument is type='bool', set it to type: bool and do NOT specify choices.

  • If an argument is type='list', specify elements.

elements:

  • Specifies the data type for list elements in case type='list'.

aliases:

  • List of optional name aliases.

  • Generally not needed and not recommended to ensure consistency in the module usage.

version_added:

  • Only needed if this option was added after initial module release; in other words, this is greater than the top (module) level version_added field.

  • This is a string, not a float, for example, for a module in ansible-core this could be version_added: '2.18'.

  • In collections, this MUST be the collection version the option was added to, not the Ansible version. For example, version_added: '1.0.0'.

suboptions:
requirements:

  • List of requirements (if applicable).

  • Include minimum versions.

  • You can use Ansible markup in this field.

seealso:

  • A list of references to other modules, documentation, or internet resources.

  • Because it is more prominent, use seealso for general references instead of notes or adding links to the module description.

  • References to modules MUST use the FQCN or ansible.builtin for modules in ansible-core.

  • Plugin references are supported since ansible-core 2.15.

  • You can use Ansible markup in the description and name fields.

  • A reference can be one of the following formats:

    seealso:

# Reference by module name
- module: cisco.aci.aci_tenant

# Reference by module name, including description
- module: cisco.aci.aci_tenant
  description: ACI module to create tenants on a Cisco ACI fabric.

# Reference by plugin name
- plugin: ansible.builtin.file
  plugin_type: lookup

# Reference by plugin name, including description
- plugin: ansible.builtin.file
  plugin_type: lookup
  description: You can use the ansible.builtin.file lookup to read files on the control node.

# Reference by rST documentation anchor
- ref: aci_guide
  description: Detailed information on how to manage your ACI infrastructure using Ansible.

# Reference by rST documentation anchor (with custom title)
- ref: The official Ansible ACI guide <aci_guide>
  description: Detailed information on how to manage your ACI infrastructure using Ansible.

# Reference by Internet resource
- name: APIC Management Information Model reference
  description: Complete reference of the APIC object model.
  link: https://developer.cisco.com/docs/apic-mim-ref/

  • If you use ref: to link to an anchor that is not associated with a title, you MUST add a title to the ref for the link to work correctly.

attributes:

  • A dictionary mapping attribute names to dictionaries describing that attribute.

  • Usually attributes are provided by documentation fragments, for example ansible.builtin.action_common_attributes and its sub-fragments. Modules and plugins use the appropriate docs fragments and fill in the support, details, and potential attribute-specific other fields.

description:

  • Required.

  • A string or a list of strings. Each string is one paragraph.

  • Explanation of what this attribute does. It should be written in full sentences.

  • You can use Ansible markup in this field.

details:

  • Generally optional, but must be provided if support is partial.

  • A string or a list of strings. Each string is one paragraph.

  • Describes how support might not work as expected by the user.

  • You can use Ansible markup in this field.

support:

  • Required.

  • Must be one of full, none, partial, or N/A.

  • Indicates whether this attribute is supported by this module or plugin.

membership:

  • MUST ONLY be provided for the attribute action_group.

  • Lists the action groups this module or action is part of.

  • A string or a list of strings.

platforms:

  • MUST ONLY be used for the attribute platform.

  • Lists the platforms the module or action supports.

  • A string or a list of strings.

version_added:

  • Only needed if this attribute’s support was extended after the module/plugin was created, in other words, this is greater than the top (module) level version_added field.

  • This is a string, and not a float, for example, version_added: '2.3'.

  • In collections, this must be the collection version the attribute’s support was added to, not the Ansible version. For example, version_added: '1.0.0'.

notes:

  • Details of any important information that does not fit in one of the above sections.

  • Do NOT list check_mode or diff information under notes. Use the attributes field instead.

  • Because it stands out better, use seealso for general references over the use of notes.

  • You can use Ansible markup in this field.

Documentation fragments

If you are writing multiple related modules, they may share common documentation, such as options, authentication details, file mode settings, notes: or seealso: entries. Rather than duplicate that information in each module’s DOCUMENTATION block, you can save it once as a doc_fragment plugin and then include it in each module’s documentation.

In Ansible, shared documentation fragments are contained in a ModuleDocFragment class in lib/ansible/plugins/doc_fragments/ or in the plugins/doc_fragments directory in a collection. To include a documentation fragment, add extends_documentation_fragment: FRAGMENT_NAME in your module documentation. Use the fully qualified collection name for the FRAGMENT_NAME (for example, kubernetes.core.k8s_auth_options).

Modules should only use items from a doc fragment if the module will implement all of the interface documented there in a manner that behaves the same as the existing modules which import that fragment. The goal is that items imported from the doc fragment will behave identically when used in another module that imports the doc fragment.

By default, only the DOCUMENTATION property from a doc fragment is inserted into the module documentation. It is possible to define additional properties in the doc fragment in order to import only certain parts of a doc fragment or mix and match as appropriate. If a property is defined in both the doc fragment and the module, the module value overrides the doc fragment.

Here is an example doc fragment named example_fragment.py:

class ModuleDocFragment(object):
    # Standard documentation
    DOCUMENTATION = r'''
    options:
      # options here
    '''

    # Additional section
    OTHER = r'''
    options:
      # other options here
    '''

To insert the contents of OTHER in a module:

extends_documentation_fragment: example_fragment.other

Or use both :

extends_documentation_fragment:
  - example_fragment
  - example_fragment.other

New in version 2.8.

Since Ansible 2.8, you can have user-supplied doc_fragments by using a doc_fragments directory adjacent to play or role, just like any other plugin.

For example, all AWS modules should include:

extends_documentation_fragment:
- aws
- ec2

Using documentation fragments in collections describes how to incorporate documentation fragments in a collection.

EXAMPLES block

Immediately after the DOCUMENTATION block comes the EXAMPLES block. Here you show users how your module works with real-world examples in multi-line plain-text YAML format. The best examples are ready for the user to copy and paste into a playbook. Review and update your examples with every change to your module.

If the module has integration tests, add the example you want to add to the integration tests to make sure it works.

Best practices are:

  • Each example should include a name: line:

EXAMPLES = r'''
- name: Ensure foo is installed
  namespace.collection.modulename:
    name: foo
    state: present
'''

  • The name: line should be capitalized and not include a trailing dot.

  • Use a fully qualified collection name (FQCN) as a part of the module’s name like in the example above.

    • For modules in ansible-core, use the ansible.builtin. identifier, for example ansible.builtin.debug.

  • If your examples use boolean options, use true/false values. Since the documentation generates boolean values as true/false, having the examples use these values as well makes the module documentation more consistent.

  • If your module returns facts that are often needed, consider adding an example of how to use them.

RETURN block

Right after the EXAMPLES block comes the RETURN block. This section documents the information the module returns for use by other modules.

If your module does not return anything (apart from the standard returns made by ansible-core), specify it as RETURN = r''' # ''' Otherwise, for each value returned, provide the following fields. All the fields are required unless specified otherwise:

return name:

Name of the returned field.

description:

Detailed description of what this value represents. Capitalized and with a trailing dot. You can use Ansible markup in this field.

returned:

When this value is returned, such as always, changed or success. This is a string and can contain any human-readable content.

type:

Data type.

elements:

If type='list', specifies the data type of the list’s elements.

sample:

One or more examples.

version_added:

Only needed if this return was extended after initial module release, in other words, this is greater than the top (module) level version_added field. This is a string, and not a float, for example, version_added: '2.3'.

contains:

Optional. To describe nested return values, set type: dict, or type: list/elements: dict, or if you really have to, type: complex, and repeat the elements above for each sub-field.

Here are two example RETURN sections, one with three simple fields and one with a complex nested field:

RETURN = r'''
dest:
    description: Destination file/path.
    returned: success
    type: str
    sample: /path/to/file.txt
src:
    description: Source file used for the copy on the target machine.
    returned: changed
    type: str
    sample: /home/httpd/.ansible/tmp/ansible-tmp-1423796390.97-147729857856000/source
md5sum:
    description: MD5 checksum of the file after running copy.
    returned: when supported
    type: str
    sample: 2a5aeecc61dc98c4d780b14b330e3282
'''

RETURN = r'''
packages:
    description: Information about package requirements.
    returned: success
    type: dict
    contains:
        missing:
            description: Packages that are missing from the system.
            returned: success
            type: list
            elements: str
            sample:
                - libmysqlclient-dev
                - libxml2-dev
        badversion:
            description: Packages that are installed but at bad versions.
            returned: success
            type: list
            elements: dict
            sample:
                - package: libxml2-dev
                  version: 2.9.4+dfsg1-2
                  constraint: ">= 3.0"
'''

Python imports

Immediately after the RETURN block, add the Python imports. All modules must use Python imports in the form:

from module_utils.basic import AnsibleModule

The use of “wildcard” imports such as from module_utils.basic import * is no longer allowed.

Note

Why don’t the imports go first?

Since the DOCUMENTATION, EXAMPLES, and RETURN blocks are essentially extra docstrings for the file and are not used by the module code itself, the import statements are placed after these special variables. Positioning the imports closer to the functional code helps consolidate related elements, improving readability, debugging, and overall comprehension.

Testing module documentation