Clean-up quotas/limits usages

[Julie Pichon]

When we moved from quotas to limits, we moved from a centralised "all quotas-related operations should be in openstack_dashboard/usages/quotas.py" to individually calling the absolute_limits API methods whenever needed, resulting sometimes in copy-pasting and duplication for certain operations. This should be cleaned up.

Additionally, quotas are still in use in places, sometimes both limits and quotas are used in the same class (e.g. BaseUsage) and it's unclear whether the quotas code is now redundant and should be removed, or if it makes sense to use it in some case. The return output from quotas and limits are different (dictionary vs list).

[Eric Peterson (ericpeterson-l)]

this might be helpful refernce:

nova sample limits results....

{"limits": {"rate": [], "absolute": {"maxServerMeta": 50, "maxPersonality": 5, "maxImageMeta": 50, "maxPersonalitySize": 10240, "maxSecurityGroupRules": 20, "maxTotalKeypairs": 100, "totalRAMUsed": 8192, "totalInstancesUsed": 8, "maxSecurityGroups": 10, "totalFloatingIpsUsed": 0, "maxTotalCores": -1, "totalSecurityGroupsUsed": 0, "maxTotalFloatingIps": 10, "maxTotalInstances": 40, "totalCoresUsed": 8, "maxTotalRAMSize": 204800}}}

sample results for volumes.....

{"limits": {"rate": [], "absolute": {"maxTotalVolumeGigabytes": 3000, "maxTotalVolumes": 20}}}

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/47919

[Eric Peterson (ericpeterson-l)]

I have a proposed solution, though I am not sure this really cleans the code up much.... it does make for easier handing of errors when quotas extension is missing. If anyone wants to continue this effort, I am ok with some additional help here ;).

[Julie Pichon (jpichon)]

I would prefer if you opened a new bug for this -- I wholly agree that falling back gracefully to using limits when the quotas extension is unavailable is useful, but this isn't really the confusion / code cleanup that this bug means to be fixing.

[Akihiro Motoki (amotoki)]

Clearing the assignee due to long inactivity.

This can be tacked as part of blueprint make-quotas-great-again.