Add hypervisor information extension.

Adds a new extension to get information about hypervisors (as opposed
to compute hosts), including a list of hypervisors matching a regular
expression (database regular expression, i.e., %'s) and a list of
hypervisors with the list of instances living on those hypervisors.

Change-Id: I2e44e82e123e5e727b49622fe5e966131658f9f6

nova/db/api.py

@@ -188,11 +188,21 @@ def service_update(context, service_id, values):
 ###################
 
 
+def compute_node_get(context, compute_id):
+    """Get a computeNode."""
+    return IMPL.compute_node_get(context, compute_id)
+
+
 def compute_node_get_all(context):
     """Get all computeNodes."""
     return IMPL.compute_node_get_all(context)
 
 
+def compute_node_search_by_hypervisor(context, hypervisor_match):
+    """Get computeNodes given a hypervisor hostname match string."""
+    return IMPL.compute_node_search_by_hypervisor(context, hypervisor_match)
+
+
 def compute_node_create(context, values):
     """Create a computeNode from the values dictionary."""
     return IMPL.compute_node_create(context, values)

nova/db/sqlalchemy/api.py

@@ -473,7 +473,7 @@ def service_update(context, service_id, values):
 
 ###################
 
-def _compute_node_get(context, compute_id, session=None):
+def compute_node_get(context, compute_id, session=None):
     result = model_query(context, models.ComputeNode, session=session).\
                      filter_by(id=compute_id).\
                      first()
@@ -491,6 +491,15 @@ def compute_node_get_all(context, session=None):
                     all()
 
 
+@require_admin_context
+def compute_node_search_by_hypervisor(context, hypervisor_match):
+    field = models.ComputeNode.hypervisor_hostname
+    return model_query(context, models.ComputeNode).\
+                    options(joinedload('service')).\
+                    filter(field.like('%%%s%%' % hypervisor_match)).\
+                    all()
+
+
 def _get_host_utilization(context, host, ram_mb, disk_gb):
     """Compute the current utilization of a given host."""
     instances = instance_get_all_by_host(context, host)
@@ -542,7 +551,7 @@ def compute_node_update(context, compute_id, values, auto_adjust):
     if auto_adjust:
         _adjust_compute_node_values_for_utilization(context, values, session)
     with session.begin(subtransactions=True):
-        compute_ref = _compute_node_get(context, compute_id, session=session)
+        compute_ref = compute_node_get(context, compute_id, session=session)
         compute_ref.update(values)
         compute_ref.save(session=session)