Developer Guide

The c7n developer install includes c7n_azure. A shortcut for creating a virtual env for development is available in the makefile:

$ make install
$ source bin/activate

This creates a virtual env in your enlistment and installs all packages as editable.

Instead, you can do pip install tools/c7n_azure/requirements.txt to install test dependencies.

Adding New Azure Resources

Install Azure Dependencies

Custodian interfaces with ARM resources using Azure’s SDKs. Install the resources SDK in setup.py.

install_requires=["azure-mgmt-authorization",
                  ...
                  "azure-mgmt-containerregistry",
                  ...

Create New Azure Resource

Create your new Azure Resource.

  • service: The Azure SDK dependency added in step 1.
  • client: Client class name of the Azure Resource SDK of the resource you added.
  • enum_spec: Is a tuple of (enum_operation, list_operation, extra_args). The resource SDK client will have a list of operations this resource has.
    Place the name of the property as the enum_operation. Next, put list as the operations.
from c7n_azure.provider import resources
from c7n_azure.resources.arm import ArmResourceManager


@resources.register('containerregistry')
class ContainerRegistry(ArmResourceManager):

    class resource_type(ArmResourceManager.resource_type):
        service = 'azure.mgmt.containerregistry'
        client = 'ContainerRegistryManagementClient'
        enum_spec = ('registries', 'list', None)
        default_report_fields = (
            'name',
            'location',
            'resourceGroup'
        )

Load New Azure Resource

Once the required dependecies are installed and created the new Azure Resource, custodian will load all registered resources. Import the resource in entry.py.

import c7n_azure.resources.container_registry

Testing

Tests for c7n_azure run automatically with other Custodian tests. See Testing for Developers for information on how to run Tox.

Test framework

c7n_azure uses VCR.py for tests. This framework is used for tests in the official Azure Python SDK.

VCRpy documentation can be found here: VCR.py documentation.

ARM templates

To ensure VCR cassetes can be easily re-recorded, there are ARM templates to deploy Azure tests infrastructure.

These templates will allow you to provision real Azure resources appropriate for recreating the VCR cassettes used by the unit tests. They will let you run the unit tests against real resources.

ARM templates and helper scripts can be found in tools/c7n_azure/tests/templates folder.

There are two scripts provision.sh and cleanup.sh to provision and delete resources.

These scripts will provision or delete all ARM templates (.json files) in this directory using resource groups named after the template files (test_<filename>).

This scripts use Azure CLI, so you need to az login and az account set -s ‘subscription name’ first.

You can optionally pass a list of file names without extension to the scripts to act only on those templates:

provision.sh vm storage
cleanup.sh storage

or do everything

provision.sh

If test method requires real infrastructure, please decorate this method with the ARM template file name to ensure this test can automatically create required infrastructure if needed.

@arm_template('template.json')
def test_template(self):

Cassettes

AzureVCRBaseTest attempts to automatically obscure keys and other secrets in cassettes and replace subscription ids, but it is required to verify cassettes don’t contain any sensitive information before submitting.

For long standing operations cassette can be modified to reduce test execution time (in case recorded cassette contains some responses with Retry-After headers or Azure SDK waits until resource is provisioned).

Running tests

You can use tox to run all tests or instead you can use pytest and run only Azure tests (or only specific set of tests). Runing recorded tests still requires some authentication, it is possible to use fake data for authorization token and subscription id.

export AZURE_ACCESS_TOKEN=fake_token
export AZURE_SUBSCRIPTION_ID=ea42f556-5106-4743-99b0-c129bfa71a47
pytest tools/c7n_azure/tests