Add a new API of get_by_pod_name for pod object

In k8s, pod name cannot be duplicated and some end users want to
get pod by name.

Change-Id: Ic8b6273de914949e4799446e68e5e2d51bfab8b9

magnum/db/api.py

@@ -549,6 +549,14 @@ class Connection(object):
         :returns: A pod.
         """
 
+    @abc.abstractmethod
+    def get_pod_by_name(self, pod_name):
+        """Return a pod.
+
+        :param pod_name: The name of a pod.
+        :returns: A pod.
+        """
+
     @abc.abstractmethod
     def get_pod_by_instance(self, instance):
         """Return a pod.

magnum/db/sqlalchemy/api.py

@@ -927,6 +927,13 @@ class Connection(api.Connection):
         except NoResultFound:
             raise exception.PodNotFound(pod=pod_uuid)
 
+    def get_pod_by_name(self, pod_name):
+        query = model_query(models.Pod).filter_by(name=pod_name)
+        try:
+            return query.one()
+        except NoResultFound:
+            raise exception.PodNotFound(pod=pod_name)
+
     def get_pods_by_bay_uuid(self, bay_uuid):
         query = model_query(models.Pod).filter_by(bay_uuid=bay_uuid)
         try:

magnum/objects/pod.py

@@ -90,6 +90,18 @@ class Pod(base.MagnumObject):
         pod = Pod._from_db_object(cls(context), db_pod)
         return pod
 
+    @base.remotable_classmethod
+    def get_by_name(cls, context, name):
+        """Find a pod based on pod name and return a :class:`Pod` object.
+
+        :param name: the name of a pod.
+        :param context: Security context
+        :returns: a :class:`Pod` object.
+        """
+        db_pod = cls.dbapi.get_pod_by_name(name)
+        pod = Pod._from_db_object(cls(context), db_pod)
+        return pod
+
     @base.remotable_classmethod
     def get_by_bay_uuid(cls, context, bay_uuid):
         """Find a pods based on bay uuid and return a :class:`Pod` object.