Developing collections — Ansible Documentation

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# Developing collections

Collections are a distribution format for Ansible content. You can use collections to package and distribute playbooks, roles, modules, and plugins. You can publish and use collections through Ansible Galaxy.

- Collection structure
  - galaxy.yml
  - docs directory
  - plugins directory
  - roles directory
  - playbooks directory
  - tests directory
- Creating collections
  - Creating a collection skeleton
  - Using documentation fragments in collections
  - Building collections
  - Trying collections locally
  - Publishing collections
  - Collection versions
- Migrating Ansible content to a collection

## Collection structure

Collections follow a simple data structure. None of the directories are required unless you have specific content that belongs in one of them. A collection does require a `galaxy.yml` file at the root level of the collection. This file contains all of the metadata that Galaxy and other tools need in order to package, build and publish the collection:

    collection/
    ├── docs/
    ├── galaxy.yml
    ├── plugins/
    │   ├── modules/
    │   │   └── module1.py
    │   ├── inventory/
    │   └── .../
    ├── README.md
    ├── roles/
    │   ├── role1/
    │   ├── role2/
    │   └── .../
    ├── playbooks/
    │   ├── files/
    │   ├── vars/
    │   ├── templates/
    │   └── tasks/
    └── tests/

Note

- Ansible only accepts `.yml` extensions for `galaxy.yml`, and `.md` for the `README` file and any files in the `/docs` folder.
- See the draft collection for an example of a full collection structure.
- Not all directories are currently in use. Those are placeholders for future features.

### galaxy.yml

A collection must have a `galaxy.yml` file that contains the necessary information to build a collection artifact. See Collection Galaxy metadata structure for details.

### docs directory

Put general documentation for the collection here. Keep the specific documentation for plugins and modules embedded as Python docstrings. Use the `docs` folder to describe how to use the roles and plugins the collection provides, role requirements, and so on. Use markdown and do not add subfolders.

Use `ansible-doc` to view documentation for plugins inside a collection:

    ansible-doc -t lookup my_namespace.my_collection.lookup1

The `ansible-doc` command requires the fully qualified collection name (FQCN) to display specific plugin documentation. In this example, `my_namespace` is the namespace and `my_collection` is the collection name within that namespace.

Note

The Ansible collection namespace is defined in the `galaxy.yml` file and is not equivalent to the GitHub repository name.

### plugins directory

Add a ‘per plugin type’ specific subdirectory here, including `module_utils` which is usable not only by modules, but by most plugins by using their FQCN. This is a way to distribute modules, lookups, filters, and so on, without having to import a role in every play.

Vars plugins are unsupported in collections. Cache plugins may be used in collections for fact caching, but are not supported for inventory plugins.

#### module_utils

When coding with `module_utils` in a collection, the Python `import` statement needs to take into account the FQCN along with the `ansible_collections` convention. The resulting Python import will look like `from ansible_collections.{namespace}.{collection}.plugins.module_utils.{util} import {something}`

The following example snippets show a Python and PowerShell module using both default Ansible `module_utils` and those provided by a collection. In this example the namespace is `ansible_example`, the collection is `community`. In the Python example the `module_util` in question is called `qradar` such that the FQCN is `ansible_example.community.plugins.module_utils.qradar`:

    from ansible.module_utils.basic import AnsibleModule
    from ansible.module_utils._text import to_text

    from ansible.module_utils.six.moves.urllib.parse import urlencode, quote_plus
    from ansible.module_utils.six.moves.urllib.error import HTTPError
    from ansible_collections.ansible_example.community.plugins.module_utils.qradar import QRadarRequest

    argspec = dict(
        name=dict(required=True, type='str'),
        state=dict(choices=['present', 'absent'], required=True),
    )

    module = AnsibleModule(
        argument_spec=argspec,
        supports_check_mode=True
    )

    qradar_request = QRadarRequest(
        module,
        headers={"Content-Type": "application/json"},
        not_rest_data_keys=['state']
    )

Note that importing something from an `__init__.py` file requires using the file name:

    from ansible_collections.namespace.collection_name.plugins.callback.__init__ import CustomBaseClass

In the PowerShell example the `module_util` in question is called `hyperv` such that the FCQN is `ansible_example.community.plugins.module_utils.hyperv`:

    #!powershell
    #AnsibleRequires -CSharpUtil Ansible.Basic
    #AnsibleRequires -PowerShell ansible_collections.ansible_example.community.plugins.module_utils.hyperv

    $spec = @{
        name = @{ required = $true; type = "str" }
        state = @{ required = $true; choices = @("present", "absent") }
    }
    $module = [Ansible.Basic.AnsibleModule]::Create($args, $spec)

    Invoke-HyperVFunction -Name $module.Params.name

    $module.ExitJson()

### roles directory

Collection roles are mostly the same as existing roles, but with a couple of limitations:

> - Role names are now limited to contain only lowercase alphanumeric characters, plus `_` and start with an alpha character.
> - Roles in a collection cannot contain plugins any more. Plugins must live in the collection `plugins` directory tree. Each plugin is accessible to all roles in the collection.

The directory name of the role is used as the role name. Therefore, the directory name must comply with the above role name rules. The collection import into Galaxy will fail if a role name does not comply with these rules.

You can migrate ‘traditional roles’ into a collection but they must follow the rules above. You man need to rename roles if they don’t conform. You will have to move or link any role-based plugins to the collection specific directories.

Note

For roles imported into Galaxy directly from a GitHub repository, setting the `role_name` value in the role’s metadata overrides the role name used by Galaxy. For collections, that value is ignored. When importing a collection, Galaxy uses the role directory as the name of the role and ignores the `role_name` metadata value.

### playbooks directory

TBD.

### tests directory

TBD. Expect tests for the collection itself to reside here.

## Creating collections

To create a collection:

1. Initialize a collection with ansible-galaxy collection init to create the skeleton directory structure.
2. Add your content to the collection.
3. Build the collection into a collection artifact with ansible-galaxy collection build.
4. Publish the collection artifact to Galaxy with ansible-galaxy collection publish.

A user can then install your collection on their systems.

Currently the `ansible-galaxy collection` command implements the following sub commands:

- `init`: Create a basic collection skeleton based on the default template included with Ansible or your own template.
- `build`: Create a collection artifact that can be uploaded to Galaxy or your own repository.
- `publish`: Publish a built collection artifact to Galaxy.
- `install`: Install one or more collections.

To learn more about the `ansible-galaxy` cli tool, see the ansible-galaxy man page.

### Creating a collection skeleton

To start a new collection:

    collection_dir#> ansible-galaxy collection init my_namespace.my_collection

Then you can populate the directories with the content you want inside the collection. See https://github.com/bcoca/collection to get a better idea of what you can place inside a collection.

### Using documentation fragments in collections

To include documentation fragments in your collection:

1. Create the documentation fragment: `plugins/doc_fragments/fragment_name`.
2. Refer to the documentation fragment with its FQCN.

    extends_documentation_fragment:
      - community.kubernetes.k8s_name_options
      - community.kubernetes.k8s_auth_options
      - community.kubernetes.k8s_resource_options
      - community.kubernetes.k8s_scale_options

Documentation fragments covers the basics for documentation fragments. The kubernetes collection includes a complete example.

You can also share documentation fragments across collections with the FQCN.

### Building collections

To build a collection, run `ansible-galaxy collection build` from inside the root directory of the collection:

    collection_dir#> ansible-galaxy collection build

This creates a tarball of the built collection in the current directory which can be uploaded to Galaxy.:

    my_collection/
    ├── galaxy.yml
    ├── ...
    ├── my_namespace-my_collection-1.0.0.tar.gz
    └── ...

Note

- Certain files and folders are excluded when building the collection artifact. This is not currently configurable and is a work in progress so the collection artifact may contain files you would not wish to distribute.
- If you used the now-deprecated `Mazer` tool for any of your collections, delete any and all files it added to your `releases/` directory before you build your collection with `ansible-galaxy`.
- You must also delete the `tests/output` directory if you have been testing with `ansible-test`.
- The current Galaxy maximum tarball size is 2 MB.

This tarball is mainly intended to upload to Galaxy as a distribution method, but you can use it directly to install the collection on target systems.

### Trying collections locally

You can try your collection locally by installing it from the tarball. The following will enable an adjacent playbook to access the collection:

    ansible-galaxy collection install my_namespace-my_collection-1.0.0.tar.gz -p ./collections

You should use one of the values configured in COLLECTIONS_PATHS for your path. This is also where Ansible itself will expect to find collections when attempting to use them. If you don’t specify a path value, `ansible-galaxy collection install` installs the collection in the first path defined in COLLECTIONS_PATHS, which by default is `~/.ansible/collections`.

Next, try using the local collection inside a playbook. For examples and more details see Using collections

### Publishing collections

You can publish collections to Galaxy using the `ansible-galaxy collection publish` command or the Galaxy UI itself. You need a namespace on Galaxy to upload your collection. See Galaxy namespaces on the Galaxy docsite for details.

Note

Once you upload a version of a collection, you cannot delete or modify that version. Ensure that everything looks okay before you upload it.

#### Getting your token or API key

To upload your collection to Galaxy, you must first obtain an API token (`--api-key` in the `ansible-galaxy` CLI command). The API token is a secret token used to protect your content.

To get your API token:

- For galaxy, go to the Galaxy profile preferences page and click API token.
- For Automation Hub, go to https://cloud.redhat.com/ansible/automation-hub/token/ and click Get API token from the version dropdown.

#### Upload using ansible-galaxy

Note

By default, `ansible-galaxy` uses https://galaxy.ansible.com as the Galaxy server (as listed in the `ansible.cfg` file under GALAXY_SERVER). If you are only publishing your collection to Ansible Galaxy, you do not need any further configuration. If you are using Red Hat Automation Hub or any other Galaxy server, see Configuring the ansible-galaxy client.

To upload the collection artifact with the `ansible-galaxy` command:

    ansible-galaxy collection publish path/to/my_namespace-my_collection-1.0.0.tar.gz --api-key=SECRET

The above command triggers an import process, just as if you uploaded the collection through the Galaxy website. The command waits until the import process completes before reporting the status back. If you wish to continue without waiting for the import result, use the `--no-wait` argument and manually look at the import progress in your My Imports page.

The API key is a secret token used by the Galaxy server to protect your content. See Getting your token or API key for details.

#### Upload a collection from the Galaxy website

To upload your collection artifact directly on Galaxy:

1. Go to the My Content page, and click the Add Content button on one of your namespaces.
2. From the Add Content dialogue, click Upload New Collection, and select the collection archive file from your local filesystem.

When uploading collections it doesn’t matter which namespace you select. The collection will be uploaded to the namespace specified in the collection metadata in the `galaxy.yml` file. If you’re not an owner of the namespace, the upload request will fail.

Once Galaxy uploads and accepts a collection, you will be redirected to the My Imports page, which displays output from the import process, including any errors or warnings about the metadata and content contained in the collection.

### Collection versions

Once you upload a version of a collection, you cannot delete or modify that version. Ensure that everything looks okay before uploading. The only way to change a collection is to release a new version. The latest version of a collection (by highest version number) will be the version displayed everywhere in Galaxy; however, users will still be able to download older versions.

Collection versions use Semantic Versioning for version numbers. Please read the official documentation for details and examples. In summary:

- Increment major (for example: x in x.y.z) version number for an incompatible API change.
- Increment minor (for example: y in x.y.z) version number for new functionality in a backwards compatible manner.
- Increment patch (for example: z in x.y.z) version number for backwards compatible bug fixes.

## Migrating Ansible content to a collection

You can experiment with migrating existing modules into a collection using the content_collector tool. The `content_collector` is a playbook that helps you migrate content from an Ansible distribution into a collection.

Warning

This tool is in active development and is provided only for experimentation and feedback at this point.

See the content_collector README for full details and usage guidelines.

See also

Using collections
  Learn how to install and use collections.
Collection Galaxy metadata structure
  Understand the collections metadata structure.
Ansible module development: getting started
  Learn about how to write Ansible modules
Mailing List
  The development mailing list
irc.freenode.net
  #ansible IRC chat channel