Move BaseService to Services directory

In preparation for embedding specific metrics in issues
https://gitlab.com/gitlab-org/gitlab-ce/issues/62971,
this commit moves the BaseService for metrics dashboards
to a new services subdirectory. This is purely for the sake
of organization and maintainability.

1 files changed, 63 insertions, 0 deletions

diff --git a/app/services/metrics/dashboard/default_embed_service.rb b/app/services/metrics/dashboard/default_embed_service.rb
new file mode 100644
index 00000000000..0967c5bcfeb
--- /dev/null
+++ b/app/services/metrics/dashboard/default_embed_service.rb
@@ -0,0 +1,63 @@
+# frozen_string_literal: true
+
+# Responsible for returning a filtered system dashboard
+# containing only the default embedded metrics. In future,
+# this class may be updated to support filtering to
+# alternate metrics/panels.
+#
+# Why isn't this filtering in a processing stage? By filtering
+# here, we ensure the dynamically-determined dashboard is cached.
+#
+# Use Gitlab::Metrics::Dashboard::Finder to retrive dashboards.
+module Metrics
+  module Dashboard
+    class DefaultEmbedService < ::Metrics::Dashboard::BaseService
+      # For the default filtering for embedded metrics,
+      # uses the 'id' key in dashboard-yml definition for
+      # identification.
+      DEFAULT_EMBEDDED_METRICS_IDENTIFIERS = %w(
+        system_metrics_kubernetes_container_memory_total
+        system_metrics_kubernetes_container_cores_total
+      ).freeze
+
+      # Returns a new dashboard with only the matching
+      # metrics from the system dashboard, stripped of groups.
+      # @return [Hash]
+      def raw_dashboard
+        panels = panel_groups.each_with_object([]) do |group, panels|
+          matched_panels = group['panels'].select { |panel| matching_panel?(panel) }
+
+          panels.concat(matched_panels)
+        end
+
+        { 'panel_groups' => [{ 'panels' => panels }] }
+      end
+
+      def cache_key
+        "dynamic_metrics_dashboard_#{metric_identifiers.join('_')}"
+      end
+
+      private
+
+      # Returns an array of the panels groups on the
+      # system dashboard
+      def panel_groups
+        ::Metrics::Dashboard::SystemDashboardService
+          .new(project, nil)
+          .raw_dashboard['panel_groups']
+      end
+
+      # Identifies a panel as "matching" if any metric ids in
+      # the panel is in the list of identifiers to collect.
+      def matching_panel?(panel)
+        panel['metrics'].any? do |metric|
+          metric_identifiers.include?(metric['id'])
+        end
+      end
+
+      def metric_identifiers
+        DEFAULT_EMBEDDED_METRICS_IDENTIFIERS
+      end
+    end
+  end
+end