Developing network resource modules¶
The resource module builder is an Ansible Playbook that helps developers scaffold and maintain an Ansible network resource module.
The resource module builder has the following capabilities:
- Uses a defined model to scaffold a resource module directory layout and initial class files.
- Scaffolds either an Ansible role or a collection.
- Subsequent uses of the resource module builder will only replace the module arspec and file containing the module docstring.
- Allows you to store complex examples along side the model in the same directory.
- Maintains the model as the source of truth for the module and use resource module builder to update the source files as needed.
- Generates working sample modules for both
<network_os>_<resource>
and<network_os>_facts
.
Accessing the resource module builder¶
To access the resource module builder:
- clone the github repository:
git clone https://github.com/ansible-network/resource_module_builder.git
- Install the requirements:
pip install -r requirements.txt
Creating a model¶
You must create a model for your new resource. The resource module builder uses this model to create:
- The scaffold for a new module
- The argspec for the new module
- The docstring for the new module
The model is then the single source of truth for both the argspec and docstring, keeping them in sync. Use the resource module builder to generate this scaffolding. For any subsequent updates to the module, update the model first and use the resource module builder to update the module argspec and docstring.
For example, the resource model builder includes the myos_interfaces.yml
sample in the models
directory, as seen below:
---
GENERATOR_VERSION: '1.0'
ANSIBLE_METADATA: |
{
'metadata_version': '1.1',
'status': ['preview'],
'supported_by': '<support_group>'
}
NETWORK_OS: myos
RESOURCE: interfaces
COPYRIGHT: Copyright 2019 Red Hat
LICENSE: gpl-3.0.txt
DOCUMENTATION: |
module: myos_interfaces
version_added: 2.9
short_description: 'Manages <xxxx> attributes of <network_os> <resource>'
description: 'Manages <xxxx> attributes of <network_os> <resource>.'
author: Ansible Network Engineer
notes:
- 'Tested against <network_os> <version>'
options:
config:
description: The provided configuration
type: list
elements: dict
suboptions:
name:
type: str
description: The name of the <resource>
some_string:
type: str
description:
- The some_string_01
choices:
- choice_a
- choice_b
- choice_c
default: choice_a
some_bool:
description:
- The some_bool.
type: bool
some_int:
description:
- The some_int.
type: int
version_added: '1.1'
some_dict:
type: dict
description:
- The some_dict.
suboptions:
property_01:
description:
- The property_01
type: str
state:
description:
- The state of the configuration after module completion.
type: str
choices:
- merged
- replaced
- overridden
- deleted
default: merged
EXAMPLES:
- deleted_example_01.txt
- merged_example_01.txt
- overridden_example_01.txt
- replaced_example_01.txt
Notice that you should include examples for each of the states that the resource supports. The resource module builder also includes these in the sample model.
See Ansible network resource models for more examples.
Using the resource module builder¶
To use the resource module builder to create a collection scaffold from your resource model:
ansible-playbook -e rm_dest=<destination for modules and module utils> \
-e structure=collection \
-e collection_org=<collection_org> \
-e collection_name=<collection_name> \
-e model=<model> \
site.yml
Where the parameters are as follows:
rm_dest
: The directory where the resource module builder places the files and directories for the resource module and facts modules.structure
: The directory layout type (role or collection)role
: Generate a role directory layout.collection
: Generate a collection directory layout.
collection_org
: The organization of the collection, required when structure=collection.collection_name
: The name of the collection, required when structure=collection.model
: The path to the model file.
To use the resource module builder to create a role scaffold:
ansible-playbook -e rm_dest=<destination for modules and module utils> \
-e structure=role \
-e model=<model> \
site.yml
Examples¶
Collection directory layout¶
This example shows the directory layout for the following:
network_os
: myosresource
: interfaces
ansible-playbook -e rm_dest=~/github/rm_example \
-e structure=collection \
-e collection_org=cidrblock \
-e collection_name=my_collection \
-e model=models/myos/interfaces/myos_interfaces.yml \
site.yml
├── docs
├── LICENSE.txt
├── playbooks
├── plugins
| ├── action
| ├── filter
| ├── inventory
| ├── modules
| | ├── __init__.py
| | ├── myos_facts.py
| | └── myos_interfaces.py
| └── module_utils
| ├── __init__.py
| └── network
| ├── __init__.py
| └── myos
| ├── argspec
| | ├── facts
| | | ├── facts.py
| | | └── __init__.py
| | ├── __init__.py
| | └── interfaces
| | ├── __init__.py
| | └── interfaces.py
| ├── config
| | ├── __init__.py
| | └── interfaces
| | ├── __init__.py
| | └── interfaces.py
| ├── facts
| | ├── facts.py
| | ├── __init__.py
| | └── interfaces
| | ├── __init__.py
| | └── interfaces.py
| ├── __init__.py
| └── utils
| ├── __init__.py
| └── utils.py
├── README.md
└── roles
Role directory layout¶
This example displays the role directory layout for the following:
network_os
: myosresource
: interfaces
ansible-playbook -e rm_dest=~/github/rm_example/roles/my_role \
-e structure=role \
-e model=models/myos/interfaces/myos_interfaces.yml \
site.yml
roles
└── my_role
├── library
│ ├── __init__.py
│ ├── myos_facts.py
│ └── myos_interfaces.py
├── LICENSE.txt
├── module_utils
│ ├── __init__.py
│ └── network
│ ├── __init__.py
│ └── myos
│ ├── argspec
│ │ ├── facts
│ │ │ ├── facts.py
│ │ │ └── __init__.py
│ │ ├── __init__.py
│ │ └── interfaces
│ │ ├── __init__.py
│ │ └── interfaces.py
│ ├── config
│ │ ├── __init__.py
│ │ └── interfaces
│ │ ├── __init__.py
│ │ └── interfaces.py
│ ├── facts
│ │ ├── facts.py
│ │ ├── __init__.py
│ │ └── interfaces
│ │ ├── __init__.py
│ │ └── interfaces.py
│ ├── __init__.py
│ └── utils
│ ├── __init__.py
│ └── utils.py
└── README.md
Using the collection¶
This example shows how to use the generated collection in a playbook:
---- - hosts: myos101 gather_facts: False tasks: - cidrblock.my_collection.myos_interfaces: register: result - debug: var: result - cidrblock.my_collection.myos_facts: - debug: var: ansible_network_resources
Using the role¶
This example shows how to use the generated role in a playbook:
- hosts: myos101
gather_facts: False
roles:
- my_role
- hosts: myos101
gather_facts: False
tasks:
- myos_interfaces:
register: result
- debug:
var: result
- myos_facts:
- debug:
var: ansible_network_resources
Resource module structure and workflow¶
The resource module structure includes the following components:
- Module
library/<ansible_network_os>_<resource>.py
.- Imports the
module_utils
resource package and callsexecute_module
API
def main(): result = <resource_package>(module).execute_module()
- Module argspec
module_utils/<ansible_network_os>/argspec/<resource>/
.- Argspec for the resource.
- Facts
module_utils/<ansible_network_os>/facts/<resource>/
.- Populate facts for the resource.
- Entry in
module_utils/<ansible_network_os>/facts/facts.py
forget_facts
API to keep<ansible_network_os>_facts
module and facts gathered for the resource module in sync for every subset. - Entry of Resource subset in FACTS_RESOURCE_SUBSETS list in
module_utils/<ansible_network_os>/facts/facts.py
to make facts collection work.
- Module package in module_utils
module_utils/<ansible_network_os>/<config>/<resource>/
.- Implement
execute_module
API that loads the configuration to device and generates the result withchanged
,commands
,before
andafter
keys. - Call
get_facts
API that returns the<resource>
configuration facts or return the difference if the device has onbox diff support. - Compare facts gathered and given key-values if diff is not supported.
- Generate final configuration.
- Utils
module_utils/<ansible_network_os>/utils
.- Utilities for the
<ansible_network_os>
platform.
Developer notes¶
The tests rely on a role generated by the resource module builder. After changes to the resource module builder, the role should be regenerated and the tests modified and run as needed. To generate the role after changes:
rm -rf rmb_tests/roles/my_role
ansible-playbook -e rm_dest=./rmb_tests/roles/my_role \
-e structure=role \
-e model=models/myos/interfaces/myos_interfaces.yml \
site.yml
Unit testing Ansible network resource modules¶
This section walks through an example of how to develop unit tests for Ansible network resource modules.
See Unit Tests and Unit Testing Ansible Modules for general documentation on Ansible unit tests for modules. Please read those pages first to understand unit tests and why and when you should use them.
注解
The structure of the unit tests matches
the structure of the code base, so the tests that reside in the test/units/modules/network
directory
are organized by module groups.
Using mock objects to unit test Ansible network resource modules¶
Mock objects (from https://docs.python.org/3/library/unittest.mock.html) can be very
useful in building unit tests for special or difficult cases, but they can also
lead to complex and confusing coding situations. One good use for mocks would be to
simulate an API. The mock
Python package is bundled with Ansible (use
import units.compat.mock
).
You can mock the device connection and output from the device as follows:
self.mock_get_config = patch('ansible.module_utils.network.common.network.Config.get_config')
self.get_config = self.mock_get_config.start()
self.mock_load_config = patch('ansible.module_utils.network.common.network.Config.load_config')
self.load_config = self.mock_load_config.start()
self.mock_get_resource_connection_config = patch('ansible.module_utils.network.common.cfg.base.get_resource_connection')
self.get_resource_connection_config = self.mock_get_resource_connection_config.start()
self.mock_get_resource_connection_facts = patch('ansible.module_utils.network.common.facts.facts.get_resource_connection')
self.get_resource_connection_facts = self.mock_get_resource_connection_facts.start()
self.mock_edit_config = patch('ansible.module_utils.network.eos.providers.providers.CliProvider.edit_config')
self.edit_config = self.mock_edit_config.start()
self.mock_execute_show_command = patch('ansible.module_utils.network.eos.facts.l2_interfaces.l2_interfaces.L2_interfacesFacts.get_device_data')
self.execute_show_command = self.mock_execute_show_command.start()
The facts file of the module now includes a new method, get_device_data
. Call get_device_data
here to emulate the device output.
Mocking device data¶
To mock fetching results from devices or provide other complex data structures that
come from external libraries, you can use fixtures
to read in pre-generated data. The text files for this pre-generated data live in test/units/modules/network/PLATFORM/fixtures/
. See for example the eos_l2_interfaces.cfg file.
Load data using the load_fixture
method and set this data as the return value of the
get_device_data
method in the facts file:
def load_fixtures(self, commands=None, transport='cli'):
def load_from_file(*args, **kwargs):
return load_fixture('eos_l2_interfaces_config.cfg')
self.execute_show_command.side_effect = load_from_file
See the unit test file test_eos_l2_interfaces for a practical example.
参见
- Unit Tests
- Ansible unit tests documentation
- Unit Tests
- Deep dive into developing unit tests for Ansible modules
- Testing Ansible
- Running tests locally including gathering and reporting coverage data
- Ansible module development: getting started
- Get started developing a module