ansible/docs/docsite/rst/dev_guide/developing_locally.rst

.. _using_local_modules_and_plugins:
.. _developing_locally:

**********************************
Adding modules and plugins locally
**********************************

The easiest, quickest, and the most popular way to extend Ansible is to use a local module or a plugin. You can create them or copy existing ones for local use. You can store a local module or plugin on your Ansible control node and share it with your team or organization. You can also share a local plugin or module by embedding it in a role and publishing it on Ansible Galaxy. If you are using roles on Ansible Galaxy, then you are already using local modules and plugins without realizing it.

If you are using an existing module or plugin but Ansible can't find it, this page is all you need. However, if you want to create a plugin or a module, go to :ref:`developing_plugins` and :ref:`developing_modules_general` topics and then return to this page to know how to add it locally. 

Extending Ansible with local modules and plugins offers lots of shortcuts such as:

* You can copy other people's modules and plugins.
* If you're writing a new module, you can choose any programming language you like.
* You don't have to clone the main Ansible repo.
* You don't have to open a pull request.
* You don't have to add tests (though we recommend that you do!).

To save a local module or plugin such that Ansible can find and use it, add the module or plugin in the appropriate directory (the directories are specified in later parts of this topic). 

.. contents::
   :local:

.. _modules_vs_plugins:

Modules and plugins: what's the difference?
===========================================
If you're looking to add local functionality to Ansible, you might wonder whether you need a module or a plugin. Here's a quick overview to help you decide between the two:

* Modules are reusable, standalone scripts that can be used by the Ansible API, the :command:`ansible` command, or the :command:`ansible-playbook` command. Modules provide a defined interface. Each module accepts arguments and returns information to Ansible by printing a JSON string to stdout before exiting. Modules execute on the target system (usually that means on a remote system) in separate processes.
* :ref:`Plugins <plugins_lookup>` augment Ansible's core functionality and execute on the control node within the ``/usr/bin/ansible`` process. Plugins offer options and extensions for the core features of Ansible - transforming data, logging output, connecting to inventory, and more.

.. _local_modules:

Adding a module locally
=======================
Ansible automatically loads all executable files found in certain directories as modules.

For local modules, use the name of the file as the module name: for example, if the module file is ``~/.ansible/plugins/modules/local_users.py``, use ``local_users`` as the module name.

To load your local modules automatically and make them available to all playbooks and roles, add them in any of these locations:

* any directory added to the ``ANSIBLE_LIBRARY`` environment variable (``$ANSIBLE_LIBRARY`` takes a colon-separated list like ``$PATH``)
* ``~/.ansible/plugins/modules/``
* ``/usr/share/ansible/plugins/modules/``

After you save your module file in one of these locations, Ansible loads it and you can use it in any local task, playbook, or role.

To confirm that ``my_custom_module`` is available:

* type ``ansible localhost -m my_custom_module``. You should see the output for that module.

or 

* type ``ansible-doc -t module my_custom_module``. You should see the documentation for that module.

.. note::

   Currently, the ``ansible-doc`` command can parse module documentation only from modules written in Python. If you have a module written in a programming language other than Python, please write the documentation in a Python file adjacent to the module file.

You can limit the availability of your local module. If you want to use a local module only with selected playbooks or only with a single role, load it in one of the following locations:

* In a selected playbook or playbooks: Store the module in a subdirectory called ``library`` in the directory that contains those playbooks.
* In a single role: Store the module in a subdirectory called ``library`` within that role.

.. _distributing_plugins:
.. _local_plugins:

Adding a plugin locally
=======================
Ansible loads plugins automatically too, and loads each type of plugin separately from a directory named for the type of plugin. Here's the full list of plugin directory names:

    * action_plugins*
    * cache_plugins
    * callback_plugins
    * connection_plugins
    * filter_plugins*
    * inventory_plugins
    * lookup_plugins
    * shell_plugins
    * strategy_plugins
    * test_plugins*
    * vars_plugins

.. note::

	After you add the plugins and verify that they are available for use, you can see the documentation for all the plugins except for the ones marked with an asterisk (*) above.

To load your local plugins automatically, add them in any of these locations:

* any directory added to the relevant ``ANSIBLE_plugin_type_PLUGINS`` environment variable (these variables, such as ``$ANSIBLE_INVENTORY_PLUGINS`` and ``$ANSIBLE_VARS_PLUGINS`` take colon-separated lists like ``$PATH``)
* the directory named for the correct ``plugin_type`` within ``~/.ansible/plugins/`` - for example, ``~/.ansible/plugins/callback``
* the directory named for the correct ``plugin_type`` within ``/usr/share/ansible/plugins/`` - for example, ``/usr/share/ansible/plugins/action``

After your plugin file is in one of these locations, Ansible loads it and you can use it in any local module, task, playbook, or role. Alternatively, you can edit your ``ansible.cfg`` file to add directories that contain local plugins. For details about adding directories of local plugins, see :ref:`ansible_configuration_settings`.

To confirm that ``plugins/plugin_type/my_custom_plugin`` is available:

* type ``ansible-doc -t <plugin_type> my_custom_lookup_plugin``. For example, ``ansible-doc -t lookup my_custom_lookup_plugin``. You should see the documentation for that plugin. This works for all plugin types except the ones marked with ``*`` in the list above  - see :ref:`ansible-doc` for more details.

You can limit the availability of your local plugin. If you want to use a local plugin only with selected playbooks or only with a single role, load it in one of the following locations:

* In a selected playbook or playbooks: Store the plugin in a subdirectory for the correct ``plugin_type`` (for example, ``callback_plugins`` or ``inventory_plugins``) in the directory that contains the playbooks.
* In a single role: Store the plugin in a subdirectory for the correct ``plugin_type`` (for example, ``cache_plugins`` or ``strategy_plugins``) within that role. When shipped as part of a role, the plugin is available as soon as the role is executed.