General host aggregates part 2

Partially implements blueprint general-host-aggregates: Scheduler Filter
* Add AggregateInstanceExtraSpecsFilter
* change db.aggregate_get_by_host to return a list of aggregates
  instead of the first aggregate
* Add optional key filter to db.aggregate_get_by_host along with test
* Add db.aggregate_metadata_get_by_host to get host aggregate metadata
* add optional key filter to db.aggregate_metadata_get_by_host
* Add AggregateTypeAffinityFilter

Change-Id: I4a3061276cc3b0c5c695eaf973b773183b3c4f4b

2 files changed, 35 insertions, 11 deletions

diff --git a/nova/db/api.py b/nova/db/api.py
index e6ebecbdf..83f4ca355 100644
--- a/nova/db/api.py
+++ b/nova/db/api.py
@@ -1828,9 +1828,18 @@ def aggregate_get(context, aggregate_id):
     return IMPL.aggregate_get(context, aggregate_id)
 
 
-def aggregate_get_by_host(context, host):
-    """Get a specific aggregate by host"""
-    return IMPL.aggregate_get_by_host(context, host)
+def aggregate_get_by_host(context, host, key=None):
+    """Get a list of aggregates that host belongs to"""
+    return IMPL.aggregate_get_by_host(context, host, key)
+
+
+def aggregate_metadata_get_by_host(context, host, key=None):
+    """Get metadata for all aggregates that host belongs to.
+
+    Returns a dictionary where each value is a set, this is to cover the case
+    where there two aggregates have different values for the same key.
+    Optional key filter"""
+    return IMPL.aggregate_metadata_get_by_host(context, host, key)
 
 
 def aggregate_update(context, aggregate_id, values):
diff --git a/nova/db/sqlalchemy/api.py b/nova/db/sqlalchemy/api.py
index 2993aaaf3..325827089 100644
--- a/nova/db/sqlalchemy/api.py
+++ b/nova/db/sqlalchemy/api.py
@@ -19,6 +19,7 @@
 
 """Implementation of SQLAlchemy backend."""
 
+from collections import defaultdict
 import copy
 import datetime
 import functools
@@ -4926,16 +4927,30 @@ def aggregate_get(context, aggregate_id):
 
 
 @require_admin_context
-def aggregate_get_by_host(context, host):
-    aggregate_host = _aggregate_get_query(context,
-                                          models.AggregateHost,
-                                          models.AggregateHost.host,
-                                          host).first()
+def aggregate_get_by_host(context, host, key=None):
+    query = model_query(context, models.Aggregate).join(
+            "_hosts").filter(models.AggregateHost.host == host)
+
+    if key:
+        query = query.join("_metadata").filter(
+        models.AggregateMetadata.key == key)
+    return query.all()
 
-    if not aggregate_host:
-        raise exception.AggregateHostNotFound(host=host)
 
-    return aggregate_get(context, aggregate_host.aggregate_id)
+@require_admin_context
+def aggregate_metadata_get_by_host(context, host, key=None):
+    query = model_query(context, models.Aggregate).join(
+            "_hosts").filter(models.AggregateHost.host == host).join(
+            "_metadata")
+
+    if key:
+        query = query.filter(models.AggregateMetadata.key == key)
+    rows = query.all()
+    metadata = defaultdict(set)
+    for agg in rows:
+        for kv in agg._metadata:
+            metadata[kv['key']].add(kv['value'])
+    return metadata
 
 
 @require_admin_context