Added Disk Capacity in cluster-data-model

Fetched information of total disk capacity from nova and added a new
resource 'disk_capacity' to NovaClusterModelCollector cluster. Also a
new resource type 'disk_capacity' was added to ResourceType.
https://bugs.launchpad.net/watcher/+bug/1553124

Change-Id: I85750f25c6d2693432da8e5e3a3d0861320f4787
Closes-Bug: #1553124

watcher/decision_engine/model/resource.py

@@ -21,6 +21,7 @@ class ResourceType(Enum):
     cpu_cores = 'num_cores'
     memory = 'memory'
     disk = 'disk'
+    disk_capacity = 'disk_capacity'
 
 
 class Resource(object):

watcher/metrics_engine/cluster_model_collector/nova.py

@@ -40,9 +40,11 @@ class NovaClusterModelCollector(api.BaseClusterModelCollector):
         mem = resource.Resource(resource.ResourceType.memory)
         num_cores = resource.Resource(resource.ResourceType.cpu_cores)
         disk = resource.Resource(resource.ResourceType.disk)
+        disk_capacity = resource.Resource(resource.ResourceType.disk_capacity)
         cluster.create_resource(mem)
         cluster.create_resource(num_cores)
         cluster.create_resource(disk)
+        cluster.create_resource(disk_capacity)
 
         flavor_cache = {}
         hypervisors = self.wrapper.get_hypervisors_list()
@@ -55,6 +57,7 @@ class NovaClusterModelCollector(api.BaseClusterModelCollector):
             # set capacity
             mem.set_capacity(hypervisor, h.memory_mb)
             disk.set_capacity(hypervisor, h.free_disk_gb)
+            disk_capacity.set_capacity(hypervisor, h.local_gb)
             num_cores.set_capacity(hypervisor, h.vcpus)
             hypervisor.state = h.state
             hypervisor.status = h.status