Merge branch 'master' into go-go-gadget-webpack

* master: (67 commits)
  Add some API endpoints for time tracking.
  use destructuring syntax instead
  add changelog yml file
  correct User_agent placement in robots.txt
  Fixing typo
  Fix Project#update_repository_size to convert MB to Bytes properly
  Remove repository trait from factories that don't need it in features
  Add the `:repository` trait to `:project` factories in Cucumber steps
  Add a `:repository` trait to the `:empty_project` factory
  Update clipboard_button text: Copy commit SHA to clipboard
  Fix search bar filter dropdown scrollbars
  get rid of log
  fix UI behaviour - only make new calls when button is clicked and dropdown is not displayed
  better UI fix - simple solution
  Disable all cops in .rubocop_todo.yml
  fix spec
  refactored a bunch of stuff based on feedback
  fix serializer
  fix bug retrieving medians
  fix specs
  ...

1 files changed, 54 insertions, 0 deletions

diff --git a/lib/gitlab/cycle_analytics/base_stage.rb b/lib/gitlab/cycle_analytics/base_stage.rb
new file mode 100644
index 00000000000..74bbcdcb3dd
--- /dev/null
+++ b/lib/gitlab/cycle_analytics/base_stage.rb
@@ -0,0 +1,54 @@
+module Gitlab
+  module CycleAnalytics
+    class BaseStage
+      include BaseQuery
+
+      def initialize(project:, options:)
+        @project = project
+        @options = options
+      end
+
+      def events
+        event_fetcher.fetch
+      end
+
+      def as_json
+        AnalyticsStageSerializer.new.represent(self).as_json
+      end
+
+      def title
+        name.to_s.capitalize
+      end
+
+      def median
+        cte_table = Arel::Table.new("cte_table_for_#{name}")
+
+        # Build a `SELECT` query. We find the first of the `end_time_attrs` that isn't `NULL` (call this end_time).
+        # Next, we find the first of the start_time_attrs that isn't `NULL` (call this start_time).
+        # We compute the (end_time - start_time) interval, and give it an alias based on the current
+        # cycle analytics stage.
+        interval_query = Arel::Nodes::As.new(
+          cte_table,
+          subtract_datetimes(base_query.dup, start_time_attrs, end_time_attrs, name.to_s))
+
+        median_datetime(cte_table, interval_query, name)
+      end
+
+      def name
+        raise NotImplementedError.new("Expected #{self.name} to implement name")
+      end
+
+      private
+
+      def event_fetcher
+        @event_fetcher ||= Gitlab::CycleAnalytics::EventFetcher[name].new(project: @project,
+                                                                          stage: name,
+                                                                          options: event_options)
+      end
+
+      def event_options
+        @options.merge(start_time_attrs: start_time_attrs, end_time_attrs: end_time_attrs)
+      end
+    end
+  end
+end