Fix uses of service_get_all_compute_by_host

There should never be more than 1 service entry for the same topic and
host, however this method returns a list of services.  All callers of
this method except for 1 already account for there being only 1 service
entry for a particular 'compute' host and only use the first entry in the
return list.

This patch renames the DB API call to be 'service_get_by_compute_host'
and returns a single entry.  All uses of the old method are adjusted
accordingly.

Change-Id: I0e0ef62f5d2e71efe756940d9fdd98aa02fef216

2 files changed, 8 insertions, 5 deletions

diff --git a/nova/db/api.py b/nova/db/api.py
index b1552b480..d7d9bd0d2 100644
--- a/nova/db/api.py
+++ b/nova/db/api.py
@@ -151,9 +151,12 @@ def service_get_all_by_host(context, host):
     return IMPL.service_get_all_by_host(context, host)
 
 
-def service_get_all_compute_by_host(context, host):
-    """Get all compute services for a given host."""
-    return IMPL.service_get_all_compute_by_host(context, host)
+def service_get_by_compute_host(context, host):
+    """Get the service entry for a given compute host.
+
+    Returns the service entry joined with the compute_node entry.
+    """
+    return IMPL.service_get_by_compute_host(context, host)
 
 
 def service_get_all_compute_sorted(context):
diff --git a/nova/db/sqlalchemy/api.py b/nova/db/sqlalchemy/api.py
index 8930f6ccc..e51d7b685 100644
--- a/nova/db/sqlalchemy/api.py
+++ b/nova/db/sqlalchemy/api.py
@@ -370,12 +370,12 @@ def service_get_all_by_host(context, host):
 
 
 @require_admin_context
-def service_get_all_compute_by_host(context, host):
+def service_get_by_compute_host(context, host):
     result = model_query(context, models.Service, read_deleted="no").\
                 options(joinedload('compute_node')).\
                 filter_by(host=host).\
                 filter_by(topic=CONF.compute_topic).\
-                all()
+                first()
 
     if not result:
         raise exception.ComputeHostNotFound(host=host)