db api: add service_get_by_uuid

This is going to be used by the Service.get_by_uuid method
which will later be used by the HostAPI to uniquely lookup
a service within a cell.

Part of blueprint service-hyper-uuid-in-api

Change-Id: Iff58296d5b05670116d4e0dc7846a260c48d84ed

2 files changed, 18 insertions, 0 deletions

diff --git a/nova/db/api.py b/nova/db/api.py
index 83d7b10b18..e0e01321f7 100644
--- a/nova/db/api.py
+++ b/nova/db/api.py
@@ -112,6 +112,13 @@ def service_get(context, service_id):
     return IMPL.service_get(context, service_id)
 
 
+def service_get_by_uuid(context, service_uuid):
+    """Get a service by it's uuid or raise ServiceNotFound if it does not
+    exist.
+    """
+    return IMPL.service_get_by_uuid(context, service_uuid)
+
+
 def service_get_minimum_version(context, binary):
     """Get the minimum service version in the database."""
     return IMPL.service_get_minimum_version(context, binary)
diff --git a/nova/db/sqlalchemy/api.py b/nova/db/sqlalchemy/api.py
index a5c0720d17..f3bb21cd02 100644
--- a/nova/db/sqlalchemy/api.py
+++ b/nova/db/sqlalchemy/api.py
@@ -475,6 +475,17 @@ def service_get(context, service_id):
     return result
 
 
+@pick_context_manager_reader
+def service_get_by_uuid(context, service_uuid):
+    query = model_query(context, models.Service).filter_by(uuid=service_uuid)
+
+    result = query.first()
+    if not result:
+        raise exception.ServiceNotFound(service_id=service_uuid)
+
+    return result
+
+
 @pick_context_manager_reader_allow_async
 def service_get_minimum_version(context, binaries):
     min_versions = context.session.query(