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

1 files changed, 33 insertions, 0 deletions

diff --git a/nova/limit/placement.py b/nova/limit/placement.py
index 2e04e015e6..95beffaff0 100644
--- a/nova/limit/placement.py
+++ b/nova/limit/placement.py
@@ -32,6 +32,12 @@ CONF = nova.conf.CONF
 # 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)