Apply capacity algorithm changes

* This also adds fields to the instance view for tracking cpu and
  memory usage as well as information on what the capacity ranges are
* Also adds a flag for enabling/disabling instances which removes them
  from all queues and has them stop processing new work
* The capacity is now based almost exclusively on some value relative
  to forks
* capacity_adjustment allows you to commit an instance to a certain
  amount of forks, cpu focused or memory focused
* Each job run adds a single fork overhead (that's the reasoning
  behind the +1)

awx/api/serializers.py

@@ -3977,8 +3977,10 @@ class InstanceSerializer(BaseSerializer):
 
     class Meta:
         model = Instance
-        fields = ("id", "type", "url", "related", "uuid", "hostname", "created", "modified",
-                  "version", "capacity", "consumed_capacity", "percent_capacity_remaining", "jobs_running")
+        read_only_fields = ('uuid', 'hostname', 'version')
+        fields = ("id", "type", "url", "related", "uuid", "hostname", "created", "modified", 'capacity_adjustment',
+                  "version", "capacity", "consumed_capacity", "percent_capacity_remaining", "jobs_running",
+                  "cpu", "memory", "cpu_capacity", "mem_capacity", "enabled")
 
     def get_related(self, obj):
         res = super(InstanceSerializer, self).get_related(obj)

awx/api/views.py

@@ -57,7 +57,7 @@ import pytz
 from wsgiref.util import FileWrapper
 
 # AWX
-from awx.main.tasks import send_notifications
+from awx.main.tasks import send_notifications, handle_ha_toplogy_changes
 from awx.main.access import get_user_queryset
 from awx.main.ha import is_ha_environment
 from awx.api.authentication import TokenGetAuthentication
@@ -560,7 +560,7 @@ class InstanceList(ListAPIView):
     new_in_320 = True
 
 
-class InstanceDetail(RetrieveAPIView):
+class InstanceDetail(RetrieveUpdateAPIView):
 
     view_name = _("Instance Detail")
     model = Instance
@@ -568,6 +568,20 @@ class InstanceDetail(RetrieveAPIView):
     new_in_320 = True
 
 
+    def update(self, request, *args, **kwargs):
+        r = super(InstanceDetail, self).update(request, *args, **kwargs)
+        if status.is_success(r.status_code):
+            obj = self.get_object()
+            if obj.enabled:
+                obj.refresh_capacity()
+            else:
+                obj.capacity = 0
+            obj.save()
+            handle_ha_toplogy_changes.apply_async()
+            r.data = InstanceSerializer(obj, context=self.get_serializer_context()).to_representation(obj)
+        return r
+
+
 class InstanceUnifiedJobsList(SubListAPIView):
 
     view_name = _("Instance Running Jobs")