horizon/doc/source/contributor/topics/microversion_support.rst

Horizon Microversion Support

Introduction

Several services use API microversions, which allows consumers of that API to specify an exact version when making a request. This can be useful in ensuring a feature continues to work as expected across many service releases.

Adding a feature that was introduced in a microversion

1. Add the feature to the MICROVERSION_FEATURES dict in openstack_dashboard/api/microversions.py under the appropriate service name. The feature should have at least two versions listed; the minimum version (i.e. the version that introduced the feature) and the current working version. Providing multiple versions reduces project maintenance overheads and helps Horizon work with older service deployments.

2. Use the is_feature_available function for your service to show or hide the function.:

   from openstack_dashboard.api import service
   
   ...
   
   def allowed(self, request):
       return service.is_feature_available('feature')

3. Send the correct microversion with get_microversion function in the API layer.:

   def resource_list(request):
       try:
           microversion = get_microversion(request, 'feature')
           client = serviceclient(request, microversion)
           return client.resource_list()

Microversion references

Nova

https://docs.openstack.org/nova/latest/reference/api-microversion-history.html

Cinder

https://docs.openstack.org/cinder/latest/contributor/api_microversion_history.html

API-WG

https://specs.openstack.org/openstack/api-wg/guidelines/microversion_specification.html