Added vms_by_host

neat/contracts_extra.py

@@ -18,6 +18,7 @@ import collections
 import libvirt
 import sqlalchemy
 import neat.db
+# import novaclient
 
 
 new_contract('deque', collections.deque)
@@ -26,3 +27,4 @@ new_contract('virConnect', libvirt.virConnect)
 new_contract('virDomain', libvirt.virDomain)
 new_contract('Table', sqlalchemy.Table)
 new_contract('Database', neat.db.Database)
+# new_contract('Client', novaclient.v1_1.client.Client)

neat/globals/manager.py

@@ -225,14 +225,40 @@ def execute_underload(config, state, host):
     :return: The updated state dictionary.
      :rtype: dict(str: *)
     """
-
-    nt = client.Client("admin", "adminpassword", "admin", "http://controller:5000/v2.0/", service_type="compute")
-    vms = nt.servers.list(detailed=True)
-    vms[0].id  # uuid
-    vms[0].__getattr__('OS-EXT-SRV-ATTR:host')  # host name
+    vms = vms_by_host(state['nova'], host)
     return state
 
 
+@contract
+def vms_by_host(nova, host):
+    """ Get VMs from the specified host using the Nova API.
+
+    :param nova: A Nova client.
+     :type nova: *
+
+    :param host: A host name.
+     :type host: str
+
+    :return: A list of VM UUIDs from the specified host.
+     :rtype: list(str)
+    """
+    return [vm.id for vm in nova.servers.list()
+            if vm_hostname(vm) == host]
+
+
+@contract
+def vm_hostname(vm):
+    """ Get the name of the host where VM is running.
+
+    :param vm: A Nova VM object.
+     :type vm: *
+
+    :return: The hostname.
+     :rtype: str
+    """
+    return vm.__getattr__('OS-EXT-SRV-ATTR:host')
+
+
 @contract
 def execute_overload(config, state, vm_uuids):
     """ Execute an iteration of the global manager

tests/globals/test_manager.py

@@ -164,3 +164,30 @@ class GlobalManager(TestCase):
             expect(manager).validate_params(config, params).and_return(True).once()
             expect(manager).execute_overload(config, state, 'vm_uuids').once()
             manager.service()
+
+    @qc(20)
+    def vms_by_host(
+        x=dict_(
+            keys=str_(of='abc123-', min_length=36, max_length=36),
+            values=str_(of='abc123-', min_length=10, max_length=10),
+            min_length=0, max_length=3
+        ),
+        y=list_(str_(of='abc123-', min_length=36, max_length=36),
+                min_length=0, max_length=3),
+        host=str_(of='abc123-', min_length=5, max_length=5)
+    ):
+        with MockTransaction:
+            extra_vms = {}
+            for vm in y:
+                extra_vms[vm] = host
+            x.update(extra_vms)
+            vms = []
+            for vm_uuid, h in x.items():
+                vm = mock(vm_uuid)
+                vm.id = vm_uuid
+                expect(manager).vm_hostname(vm).and_return(h).once()
+                vms.append(vm)
+            nova = mock('nova')
+            nova.servers = mock('servers')
+            expect(nova.servers).list().and_return(vms).once()
+            assert set(manager.vms_by_host(nova, host)) == set(y)