.. _developing_modules_documenting: .. _module_documenting: ******************************* 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 :ref:`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: * :ref:`submission checklist ` * :ref:`programming tips ` * :ref:`testing ` before you open a pull request 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: .. contents:: :depth: 1 :local: If you are curious why ``imports`` are not located at the top of the file, see the :ref:`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 :ref:`adjacent_yaml_doc` for details. .. _shebang: 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/``) so ``ansible__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`` logic. * Passing arguments to the interpreter in the shebang does not work; for example, ``#!/usr/bin/env python``. 2. Follow the shebang immediately with ``# -*- coding: utf-8 -*-`` to clarify that the file is UTF-8 encoded. .. _copyright: Copyright and license ===================== * After the shebang and UTF-8 encoding lines, add a `copyright line `_ with the original copyright holder and a license declaration. * The license declaration should be one line ONLY, not the full GPL prefix, as follows: .. code-block:: python #!/usr/bin/python # -*- coding: utf-8 -*- # Copyright: Contributors to the Ansible project # GNU General Public License v3.0+ (see COPYING or https://www.gnu.org/licenses/gpl-3.0.txt) * Additions to the module MUST NOT include additional copyright lines beyond the default statement, unless the default copyright statement is missing. .. code-block:: python # Copyright: Contributors to the Ansible project * Any legal review will include the source control history, so an exhaustive copyright header is not necessary. * Please do NOT include a copyright year. * If the existing copyright statement includes a year, do NOT edit the existing copyright year. * Do NOT modify the existing copyright header without permission from the copyright author. .. _documentation_block: DOCUMENTATION block =================== Before committing your module documentation, please test it at the :ref:`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: * Start by copying our `example documentation string `_. * Write the block in an :ref:`editor with YAML syntax highlighting ` before you include it in your Python file. * If you run into syntax issues that are difficult to resolve, use the `YAML Lint `_ website to help validate the YAML. 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. * 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 :ref:`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 :ref:`list_of_collections` 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. :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. :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: * Marks modules that will be removed in future releases. See also :ref:`module_lifecycle`. :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. :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: * If this option takes a dict or list of dicts, you can define the structure here. * See :ansplugin:`azure.azcollection.azure_rm_securitygroup#module`, :ansplugin:`azure.azcollection.azure_rm_azurefirewall#module`, and :ansplugin:`openstack.cloud.baremetal_node_action#module` for examples. :requirements: * List of requirements (if applicable). * Include minimum versions. :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. * A reference can be one of the following formats: .. code-block:: yaml+jinja 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 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. :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. :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``. .. _module_documents_linking: Linking within module documentation ----------------------------------- You can link from your module documentation to other module docs, other resources on docs.ansible.com, and resources elsewhere on the internet with the help of some pre-defined macros. The correct formats for these macros are: * ``R()`` for cross-references with a heading (supported since Ansible 2.10). For example: ``See R(Cisco IOS Platform Guide,ios_platform_options)``. Use the RST anchor for the cross-reference. See :ref:`adding_anchors_rst` for details. * For links outside of your collection, use ``R()`` if available. Otherwise, use ``U()`` or ``L()`` with full URLs (not relative links). * To refer to a group of modules in a collection, use ``R()``. When a collection is not the right granularity, use ``C(..)``, for example: - ``Refer to the R(kubernetes.core collection, plugins_in_kubernetes.core) for information on managing kubernetes clusters.`` - ``The C(win_*) modules (spread across several collections) allow you to manage various aspects of windows hosts.`` * ``L()`` for links with a heading. For example: ``See L(Ansible Automation Platform,https://www.ansible.com/products/automation-platform).`` As of Ansible 2.10, do not use ``L()`` for relative links between Ansible documentation and collection documentation. * ``U()`` for URLs. For example: ``See U(https://www.ansible.com/products/automation-platform) for an overview.`` * ``M()`` for module names. For example: ``See also M(ansible.builtin.yum) or M(community.general.apt_rpm)``. * FQCNs MUST be used, short names will create broken links; use ``ansible.builtin`` for modules in ansible-core. * ``P()`` for plugin names (supported since ansible-core 2.15). For example: ``See also P(ansible.builtin.file#lookup) or P(community.general.json_query#filter)``. * This can also reference roles: ``P(community.sops.install#role)``. * FQCNs must be used, short names will create broken links; use ``ansible.builtin`` for plugins in ansible-core. .. note:: If you are creating your own documentation site, you will need to use the `intersphinx extension `_ to convert ``R()`` and ``M()`` to the correct links. .. _semantic_markup: Semantic markup within module documentation ------------------------------------------- Use the semantic markup to highlight option names, option values, and environment variables. The markup processor formats these highlighted terms in a uniform way. With semantic markup, we can modify how the output looks without changing underlying code. The correct formats for semantic markup are as follows: * ``O()`` for option names, whether mentioned alone or with values. For example: ``Required if O(state=present).`` and ``Use with O(force) to require secure access.`` * ``V()`` for option values when mentioned alone. For example: ``Possible values include V(monospace) and V(pretty).`` * ``RV()`` for return value names, whether mentioned alone or with values. For example: ``The module returns RV(changed=true) in case of changes.`` and ``Use the RV(stdout) return value for standard output.`` * ``E()`` for environment variables. For example: ``If not set, the environment variable E(ACME_PASSWORD) will be used.`` The parameters for these formatting functions can use escaping with backslashes: ``V(foo(bar="a\\b"\), baz)`` results in the formatted value ``foo(bar="a\b"), baz)``. Rules for using O() and RV() ~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Rules for using ``O()`` and ``RV()`` are very strict. You must follow syntax rules so that documentation renderers can create hyperlinks for the options and return values, respectively. The allowed syntaxes are as follows: * To reference an option for the current plugin/module, or the entrypoint of the current role (inside role entrypoint documentation), use ``O(option)`` and ``O(option=value)``. * To reference an option for another entrypoint ``entrypoint`` from inside role documentation, use ``O(entrypoint:option)`` and ``O(entrypoint:option=name)``. The entrypoint information can be ignored by the documentation renderer, turned into a link to that entrypoint, or even directly to the option of that entrypoint. * To reference an option for *another* plugin/module ``plugin.fqcn.name`` of type ``type``, use ``O(plugin.fqcn.name#type:option)`` and ``O(plugin.fqcn.name#type:option=value)``. For modules, use ``type=module``. The FQCN and plugin type can be ignored by the documentation renderer, turned into a link to that plugin, or even directly to the option of that plugin. * To reference an option for entrypoint ``entrypoint`` of *another* role ``role.fqcn.name``, use ``O(role.fqcn.name#role:entrypoint:option)`` and ``O(role.fqcn.name#role:entrypoint:option=value)``. The FQCN and entrypoint information can be ignored by the documentation renderer, turned into a link to that entrypoint, or even directly to the option of that entrypoint. * To reference options that do not exist (for example, options that were removed in an earlier version), use ``O(ignore:option)`` and ``O(ignore:option=value)``. The ``ignore:`` part will not be shown to the user by documentation rendering. Option names can refer to suboptions by listing the path to the option separated by dots. For example, if you have an option ``foo`` with suboption ``bar``, then you must use ``O(foo.bar)`` to reference that suboption. You can add array indications like ``O(foo[].bar)`` or even ``O(foo[-1].bar)`` to indicate specific list elements. Everything between ``[`` and ``]`` pairs will be ignored to determine the real name of the option. For example, ``O(foo[foo | length - 1].bar[])`` results in the same link as ``O(foo.bar)``, but the text ``foo[foo | length - 1].bar[]`` displays instead of ``foo.bar``. The same syntaxes can be used for ``RV()``, except that these will refer to return value names instead of option names; for example ``RV(ansible.builtin.service_facts#module:ansible_facts.services)`` refers to the :ansretval:`ansible.builtin.service_facts#module:ansible_facts.services` fact returned by the :ansplugin:`ansible.builtin.service_facts module `. Format macros within module documentation ----------------------------------------- While it is possible to use standard Ansible formatting macros to control the look of other terms in module documentation, you should do so sparingly. Possible macros include the following: * ``C()`` for ``monospace`` (code) text. For example: ``This module functions like the unix command C(foo).`` * ``B()`` for bold text. * ``I()`` for italic text. * ``HORIZONTALLINE`` for a horizontal rule (the ``
`` html tag) to separate long descriptions. Note that ``C()``, ``B()``, and ``I()`` do **not allow escaping**, and thus cannot contain the value ``)`` as it always ends the formatting sequence. If you need to use ``)`` inside ``C()``, we recommend to use ``V()`` instead; see the above section on semantic markup. .. _module_docs_fragments: 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``: .. code-block:: python 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: .. code-block:: yaml+jinja extends_documentation_fragment: example_fragment.other Or use both : .. code-block:: yaml+jinja extends_documentation_fragment: - example_fragment - example_fragment.other .. versionadded:: 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: .. code-block:: yaml+jinja extends_documentation_fragment: - aws - ec2 :ref:`docfragments_collections` describes how to incorporate documentation fragments in a collection. .. _examples_block: 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: .. code-block:: text 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: 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. :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: .. code-block:: text 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: Python imports ============== Immediately after the ``RETURN`` block, add the Python imports. All modules must use Python imports in the form: .. code-block:: python 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. .. _dev_testing_module_documentation: Testing module documentation ============================ * Before committing your module documentation, please test it on the command line and as HTML as described on the :ref:`testing_module_documentation` page. * To test documentation in collections, please see :ref:`build_collection_docsite`.