basic fact search grammar

* Establish a base grammar for handling json path specification and
value matching. With boolean logic support and parenthesis grouping
i.e. (a.b.c="value") and ((a.b="foo") or (a="bar"))
* generate Q() results for passing to Host.objects.filter()
* Hooked up via /api/v1/hosts?host_filter=...
* DynamicFilterField added to store host filter as string with grammar
parser attached as static methods for later use by DynamicInventory &
continued use by host_filter=...

awx/api/filters.py

@@ -75,7 +75,7 @@ class FieldLookupBackend(BaseFilterBackend):
     '''
 
     RESERVED_NAMES = ('page', 'page_size', 'format', 'order', 'order_by',
-                      'search', 'type')
+                      'search', 'type', 'host_filter')
 
     SUPPORTED_LOOKUPS = ('exact', 'iexact', 'contains', 'icontains',
                          'startswith', 'istartswith', 'endswith', 'iendswith',

awx/api/views.py

@@ -78,6 +78,7 @@ from awx.api.metadata import RoleMetadata
 from awx.main.consumers import emit_channel_notification
 from awx.main.models.unified_jobs import ACTIVE_STATES
 from awx.main.scheduler.tasks import run_job_complete
+from awx.main.fields import DynamicFilterField
 
 logger = logging.getLogger('awx.api.views')
 
@@ -1701,6 +1702,14 @@ class HostList(ListCreateAPIView):
     serializer_class = HostSerializer
     capabilities_prefetch = ['inventory.admin']
 
+    def get_queryset(self):
+        qs = super(HostList, self).get_queryset()
+        filter_string = self.request.query_params.get('host_filter', None)
+        if filter_string:
+            filter_q = DynamicFilterField.filter_string_to_q(filter_string)
+            qs = qs.filter(filter_q)
+        return qs
+
 
 class HostDetail(RetrieveUpdateDestroyAPIView):