DRY create_element by moving to parent class

Move create_element to the parent class and expect the child
class to only define metric_dashboard. This is to ensure consistency
across classes

ee/lib/banzai/filter/inline_alert_metrics_filter.rb

@@ -6,17 +6,6 @@ module Banzai
     # reference to an alert dashboard.
     class InlineAlertMetricsFilter < ::Banzai::Filter::InlineEmbedsFilter
       include ::Gitlab::Routing
-
-      # Placeholder element for the frontend to use as an
-      # injection point for charts.
-      def create_element(params)
-        doc.document.create_element(
-          'div',
-          class: 'js-render-metrics',
-          'data-dashboard-url': metrics_dashboard_url(params)
-        )
-      end
-
       # Search params for selecting alert metrics links. A few
       # simple checks is enough to boost performance without
       # the cost of doing a full regex match.

ee/lib/banzai/filter/inline_cluster_metrics_filter.rb

@@ -3,14 +3,6 @@
 module Banzai
   module Filter
     class InlineClusterMetricsFilter < ::Banzai::Filter::InlineEmbedsFilter
-      def create_element(params)
-        doc.document.create_element(
-          'div',
-          class: 'js-render-metrics',
-          'data-dashboard-url': metrics_dashboard_url(params)
-        )
-      end
-
       def embed_params(node)
         url = node['href']
 

lib/banzai/filter/inline_embeds_filter.rb

@@ -22,11 +22,18 @@ module Banzai
         doc
       end
 
-      # Implement in child class.
+      # Child class must provide the metrics_dashboard_url.
       #
       # Return a Nokogiri::XML::Element to embed in the
-      # markdown.
+      # markdown which provides a url to the metric_dashboard endpoint where
+      # data can be requested through a prometheus proxy. InlineMetricsRedactorFilter
+      # is responsible for premissions to see this div (and relies on the class 'js-render-metrics' ).
       def create_element(params)
+        doc.document.create_element(
+          'div',
+          class: 'js-render-metrics',
+          'data-dashboard-url': metrics_dashboard_url(params)
+        )
       end
 
       # Implement in child class unless overriding #embed_params
@@ -71,6 +78,13 @@ module Banzai
           Gitlab::Metrics::Dashboard::Url.parse_query(url)
         end
       end
+
+      # Implement in child class.
+      #
+      # Provides a full url to request the relevant panels of metric data.
+      def metrics_dashboard_url
+        raise NotImplementedError
+      end
     end
   end
 end

lib/banzai/filter/inline_grafana_metrics_filter.rb

@@ -10,11 +10,7 @@ module Banzai
       def create_element(params)
         begin_loading_dashboard(params[:url])
 
-        doc.document.create_element(
-          'div',
-          class: 'js-render-metrics',
-          'data-dashboard-url': metrics_dashboard_url(params)
-        )
+        super
       end
 
       def embed_params(node)

lib/banzai/filter/inline_metrics_filter.rb

@@ -5,16 +5,6 @@ module Banzai
     # HTML filter that inserts a placeholder element for each
     # reference to a metrics dashboard.
     class InlineMetricsFilter < Banzai::Filter::InlineEmbedsFilter
-      # Placeholder element for the frontend to use as an
-      # injection point for charts.
-      def create_element(params)
-        doc.document.create_element(
-          'div',
-          class: 'js-render-metrics',
-          'data-dashboard-url': metrics_dashboard_url(params)
-        )
-      end
-
       # Search params for selecting metrics links. A few
       # simple checks is enough to boost performance without
       # the cost of doing a full regex match.