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

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.

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.

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 collection 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.

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.

Upload using ansible-galaxy

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 Ansible Galaxy to protect your content. You can find your API key at your Galaxy profile preferences page.

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 Sematic 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