Implement admin_filter_first in Instances and Images Admin Views

Implementing ADMIN_FILTER_DATA_FIRST setting will allow operators to
require admin users provide a search criteria first before loading
data into the Admin views.
Starting with Instances and Images admin views since they already have
server side filtering options.

Implements blueprint: admin-views-filter-first

Change-Id: I846690854fd443bb98692674bf9fe6733dd04263

doc/source/topics/settings.rst

@@ -1542,6 +1542,17 @@ Can be used to selectively disable certain costly extensions for performance
 reasons.
 
 
+``ADMIN_FILTER_DATA_FIRST``
+---------------------------
+
+.. versionadded:: 10.0.0(Newton)
+
+Default: ``False``
+
+If True, when admin views load, an empty table will be rendered and the
+user will be asked to provide a search criteria first (in case no search
+criteria was provided) before loading any data.
+
 ``OPERATION_LOG_ENABLED``
 -------------------------
 

horizon/tables/base.py

@@ -1063,6 +1063,11 @@ class DataTableOptions(object):
                                       'data_type_name',
                                       "_table_data_type")
 
+        self.filter_first_message = \
+            getattr(options,
+                    'filter_first_message',
+                    _('Please specify a search criteria first.'))
+
 
 class DataTableMetaclass(type):
     """Metaclass to add options to DataTable class and collect columns."""
@@ -1177,6 +1182,8 @@ class DataTable(object):
         self.breadcrumb = None
         self.current_item_id = None
         self.permissions = self._meta.permissions
+        self.needs_filter_first = False
+        self._filter_first_message = self._meta.filter_first_message
 
         # Create a new set
         columns = []
@@ -1324,6 +1331,12 @@ class DataTable(object):
         """Returns the message to be displayed when there is no data."""
         return self._no_data_message
 
+    def get_filter_first_message(self):
+        """Return the message to be displayed when the user needs to provide
+        first a search criteria before loading any data.
+        """
+        return self._filter_first_message
+
     def get_object_by_id(self, lookup):
         """Returns the data object from the table's dataset which matches
         the ``lookup`` parameter specified. An error will be raised if

horizon/tables/views.py

@@ -14,6 +14,7 @@
 
 from collections import defaultdict
 
+from django.conf import settings
 from django import shortcuts
 
 from horizon import views
@@ -30,9 +31,11 @@ class MultiTableMixin(object):
         self.table_classes = getattr(self, "table_classes", [])
         self._data = {}
         self._tables = {}
-
         self._data_methods = defaultdict(list)
         self.get_data_methods(self.table_classes, self._data_methods)
+        self.admin_filter_first = getattr(settings,
+                                          'ADMIN_FILTER_DATA_FIRST',
+                                          False)
 
     def _get_data_dict(self):
         if not self._data:
@@ -116,10 +119,15 @@ class MultiTableMixin(object):
     def has_more_data(self, table):
         return False
 
+    def needs_filter_first(self, table):
+        return False
+
     def handle_table(self, table):
         name = table.name
         data = self._get_data_dict()
         self._tables[name].data = data[table._meta.name]
+        self._tables[name].needs_filter_first = \
+            self.needs_filter_first(table)
         self._tables[name]._meta.has_more_data = self.has_more_data(table)
         self._tables[name]._meta.has_prev_data = self.has_prev_data(table)
         handled = self._tables[name].maybe_handle()

horizon/templates/horizon/common/_data_table.html

@@ -46,7 +46,11 @@
       {{ row.render }}
     {% empty %}
     <tr class="{% cycle 'odd' 'even' %} empty">
+      {% if table.needs_filter_first %}
+        <td colspan="{{ columns|length }}">{{ table.get_filter_first_message }}</td>
+      {% else %}
         <td colspan="{{ columns|length }}">{{ table.get_empty_message }}</td>
+      {% endif  %}
     </tr>
     {% endfor %}
     </tbody>

openstack_dashboard/dashboards/admin/images/tests.py

@@ -68,6 +68,13 @@ class ImagesViewTest(test.BaseAdminViewTests):
         self.assertEqual(len(res.context['images_table'].data),
                          len(self.images.list()))
 
+    @test.update_settings(ADMIN_FILTER_DATA_FIRST=True)
+    def test_images_list_with_admin_filter_first(self):
+        res = self.client.get(reverse('horizon:admin:images:index'))
+        self.assertTemplateUsed(res, 'admin/images/index.html')
+        images = res.context['table'].data
+        self.assertItemsEqual(images, [])
+
     @override_settings(API_RESULT_PAGE_SIZE=2)
     @test.create_stubs({api.glance: ('image_list_detailed',),
                         api.keystone: ('tenant_list',)})

openstack_dashboard/dashboards/admin/images/views.py

@@ -41,6 +41,7 @@ LOG = logging.getLogger(__name__)
 
 
 class IndexView(tables.DataTableView):
+    DEFAULT_FILTERS = {'is_public': None}
     table_class = project_tables.AdminImagesTable
     template_name = 'admin/images/index.html'
     page_title = _("Images")
@@ -51,13 +52,27 @@ class IndexView(tables.DataTableView):
     def has_more_data(self, table):
         return self._more
 
+    def needs_filter_first(self, table):
+        return self._needs_filter_first
+
     def get_data(self):
         images = []
+
         if not policy.check((("image", "get_images"),), self.request):
             msg = _("Insufficient privilege level to retrieve image list.")
             messages.info(self.request, msg)
             return images
         filters = self.get_filters()
+
+        if self.admin_filter_first and \
+                len(filters) == len(self.DEFAULT_FILTERS):
+            self._prev = False
+            self._more = False
+            self._needs_filter_first = True
+            return images
+
+        self._needs_filter_first = False
+
         prev_marker = self.request.GET.get(
             project_tables.AdminImagesTable._meta.prev_pagination_param, None)
 
@@ -97,7 +112,7 @@ class IndexView(tables.DataTableView):
         return images
 
     def get_filters(self):
-        filters = {'is_public': None}
+        filters = self.DEFAULT_FILTERS.copy()
         filter_field = self.table.get_filter_field()
         filter_string = self.table.get_filter_string()
         filter_action = self.table._meta._filter_action

openstack_dashboard/dashboards/admin/instances/tests.py

@@ -400,3 +400,10 @@ class InstanceViewTest(test.BaseAdminViewTests):
         res = self.client.get(url)
 
         self.assertRedirectsNoFollow(res, INDEX_URL)
+
+    @test.update_settings(ADMIN_FILTER_DATA_FIRST=True)
+    def test_index_with_admin_filter_first(self):
+        res = self.client.get(INDEX_URL)
+        self.assertTemplateUsed(res, 'admin/instances/index.html')
+        instances = res.context['table'].data
+        self.assertItemsEqual(instances, [])

openstack_dashboard/dashboards/admin/instances/views.py

@@ -70,11 +70,27 @@ class AdminIndexView(tables.DataTableView):
     def has_more_data(self, table):
         return self._more
 
+    def needs_filter_first(self, table):
+        return self._needs_filter_first
+
     def get_data(self):
         instances = []
         marker = self.request.GET.get(
             project_tables.AdminInstancesTable._meta.pagination_param, None)
-        search_opts = self.get_filters({'marker': marker, 'paginate': True})
+        default_search_opts = {'marker': marker, 'paginate': True}
+
+        search_opts = self.get_filters(default_search_opts.copy())
+
+        """If admin_filter_first is set and if there are not other filters
+        selected, then search criteria must be provided and return an empty
+        list"""
+        if self.admin_filter_first and \
+                len(search_opts) == len(default_search_opts):
+            self._needs_filter_first = True
+            self._more = False
+            return instances
+
+        self._needs_filter_first = False
         # Gather our tenants to correlate against IDs
         try:
             tenants, has_more = api.keystone.tenant_list(self.request)

openstack_dashboard/local/local_settings.py.example

@@ -771,3 +771,8 @@ REST_API_REQUIRED_SETTINGS = ['OPENSTACK_HYPERVISOR_FEATURES',
 # until today (if set to None). This setting should be used to limit the amount
 # of data fetched by default when rendering the Overview panel.
 #OVERVIEW_DAYS_RANGE = 1
+
+# To allow operators to require admin users provide a search criteria first
+# before loading any data into the admin views, set the following attribute to
+# True
+#ADMIN_FILTER_DATA_FIRST=False

releasenotes/notes/bp-admin-views-filter-first-5b0d8a02b1271135.yaml

@@ -0,0 +1,7 @@
+---
+features:
+  - >
+    [`blueprint admin-views-filter-first <https://blueprints.launchpad.net/horizon/+spec/admin-views-filter-first>`_]
+    This blueprint provides a configurable setting to allow operators
+    require admin users to provide a search criteria first before loading data
+    into admin views.