Add legacy limits and usage to placement unified limits

Before we can update the API to say what limits are set in keystone we
need to logic to pull that information from keystone.

blueprint unified-limits-nova

Change-Id: I322d5143f3088b04d1d990880b57afc9dc08af6c

Author: JohnGarbutt

nova/limit/placement.py

@@ -32,6 +32,12 @@
 # Cache to avoid repopulating ksa state
 PLACEMENT_CLIENT = None
 
+LEGACY_LIMITS = {
+    "servers": "instances",
+    "class:VCPU": "cores",
+    "class:MEMORY_MB": "ram",
+}
+
 
 def _get_placement_usages(context, project_id):
     global PLACEMENT_CLIENT
@@ -166,3 +172,30 @@ def enforce_num_instances_and_flavor(context, project_id, flavor, is_bfvm,
 
     # no problems with max_count, so we return max count
     return max_count
+
+
+def _convert_keys_to_legacy_name(new_dict):
+    legacy = {}
+    for new_name, old_name in LEGACY_LIMITS.items():
+        # defensive incase oslo or keystone doesn't give us an answer
+        legacy[old_name] = new_dict.get(new_name) or 0
+    return legacy
+
+
+def get_legacy_default_limits():
+    enforcer = limit.Enforcer(lambda: None)
+    new_limits = enforcer.get_registered_limits(LEGACY_LIMITS.keys())
+    return _convert_keys_to_legacy_name(dict(new_limits))
+
+
+def get_legacy_project_limits(project_id):
+    enforcer = limit.Enforcer(lambda: None)
+    new_limits = enforcer.get_project_limits(project_id, LEGACY_LIMITS.keys())
+    return _convert_keys_to_legacy_name(dict(new_limits))
+
+
+def get_legacy_counts(context, project_id):
+    resource_names = list(LEGACY_LIMITS.keys())
+    resource_names.sort()
+    new_usage = _get_usage(context, project_id, resource_names)
+    return _convert_keys_to_legacy_name(new_usage)

nova/tests/unit/limit/test_placement.py

@@ -16,6 +16,7 @@
 
 from oslo_config import cfg
 from oslo_limit import exception as limit_exceptions
+from oslo_limit import fixture as limit_fixture
 from oslo_limit import limit
 from oslo_utils.fixture import uuidsentinel as uuids
 
@@ -309,3 +310,44 @@ def test_enforce_num_instances_and_flavor_placement_fail(self, mock_limit):
 
         expected = str(mock_enforcer.enforce.side_effect)
         self.assertEqual(expected, str(e))
+
+
+class GetLegacyLimitsTest(test.NoDBTestCase):
+    def setUp(self):
+        super(GetLegacyLimitsTest, self).setUp()
+        self.new = {"servers": 1, "class:VCPU": 2, "class:MEMORY_MB": 3}
+        self.legacy = {"instances": 1, "cores": 2, "ram": 3}
+        self.resources = ["servers", "class:VCPU", "class:MEMORY_MB"]
+        self.resources.sort()
+        self.flags(driver=limit_utils.UNIFIED_LIMITS_DRIVER, group="quota")
+
+    def test_convert_keys_to_legacy_name(self):
+        limits = placement_limits._convert_keys_to_legacy_name(self.new)
+        self.assertEqual(self.legacy, limits)
+
+    def test_get_legacy_default_limits(self):
+        reglimits = {'servers': 1, 'class:VCPU': 2}
+        self.useFixture(limit_fixture.LimitFixture(reglimits, {}))
+        limits = placement_limits.get_legacy_default_limits()
+        self.assertEqual({'cores': 2, 'instances': 1, 'ram': 0}, limits)
+
+    def test_get_legacy_project_limits(self):
+        reglimits = {'servers': 5, 'class:MEMORY_MB': 7}
+        projlimits = {uuids.project_id: {'servers': 1}}
+        self.useFixture(limit_fixture.LimitFixture(reglimits, projlimits))
+        limits = placement_limits.get_legacy_project_limits(uuids.project_id)
+        self.assertEqual({'instances': 1, 'cores': 0, 'ram': 7}, limits)
+
+    @mock.patch.object(report.SchedulerReportClient,
+                       "get_usages_counts_for_limits")
+    @mock.patch.object(objects.InstanceMappingList, "get_counts")
+    @mock.patch.object(quota, "is_qfd_populated")
+    def test_get_legacy_counts(self, mock_qfd, mock_counts, mock_placement):
+        mock_qfd.return_value = True
+        mock_counts.return_value = {"project": {"instances": 1}}
+        mock_placement.return_value = {
+            "VCPU": 2, "CUSTOM_BAREMETAL": 2, "MEMORY_MB": 3,
+        }
+        counts = placement_limits.get_legacy_counts(
+            "context", uuids.project_id)
+        self.assertEqual(self.legacy, counts)