Merge branch 'feature/cycle-analytics-events' into 'master'

Cycle Analytics: Events per stage

Adds list of events to each stage:

- Issue: list of issues created in the last XX days, that have been labeled or added to a milestone.
- Plan: list of commits that reference for the fist time an issue from the last stage.
- Code: list of MR created in this stage
- Test: List of unique builds triggered by the commits.
- Review: List of MR merged
- Staging: List of deployed builds
- Production: list of issues with the time from idea to production

Fixes #23449 

- [x] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added
- [ ] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)
- Tests
  - [x] Added for this feature/bug
  - [x] All builds are passing
- [x] Conform by the [merge request performance guides](http://docs.gitlab.com/ce/development/merge_request_performance_guidelines.html)
- [x] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [x] Branch has no merge conflicts with `master` (if it does - rebase it please)
- [ ] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

See merge request !6859

2 files changed, 9 insertions, 56 deletions

diff --git a/app/models/cycle_analytics.rb b/app/models/cycle_analytics.rb
index 8ed4a56b19b..314a1ce9b63 100644
--- a/app/models/cycle_analytics.rb
+++ b/app/models/cycle_analytics.rb
@@ -1,12 +1,8 @@
 class CycleAnalytics
-  include Gitlab::Database::Median
-  include Gitlab::Database::DateTime
-
-  DEPLOYMENT_METRIC_STAGES = %i[production staging]
-
   def initialize(project, from:)
     @project = project
     @from = from
+    @fetcher = Gitlab::CycleAnalytics::MetricsFetcher.new(project: project, from: from, branch: nil)
   end
 
   def summary
@@ -14,90 +10,46 @@ class CycleAnalytics
   end
 
   def issue
-    calculate_metric(:issue,
+    @fetcher.calculate_metric(:issue,
                      Issue.arel_table[:created_at],
                      [Issue::Metrics.arel_table[:first_associated_with_milestone_at],
                       Issue::Metrics.arel_table[:first_added_to_board_at]])
   end
 
   def plan
-    calculate_metric(:plan,
+    @fetcher.calculate_metric(:plan,
                      [Issue::Metrics.arel_table[:first_associated_with_milestone_at],
                       Issue::Metrics.arel_table[:first_added_to_board_at]],
                      Issue::Metrics.arel_table[:first_mentioned_in_commit_at])
   end
 
   def code
-    calculate_metric(:code,
+    @fetcher.calculate_metric(:code,
                      Issue::Metrics.arel_table[:first_mentioned_in_commit_at],
                      MergeRequest.arel_table[:created_at])
   end
 
   def test
-    calculate_metric(:test,
+    @fetcher.calculate_metric(:test,
                      MergeRequest::Metrics.arel_table[:latest_build_started_at],
                      MergeRequest::Metrics.arel_table[:latest_build_finished_at])
   end
 
   def review
-    calculate_metric(:review,
+    @fetcher.calculate_metric(:review,
                      MergeRequest.arel_table[:created_at],
                      MergeRequest::Metrics.arel_table[:merged_at])
   end
 
   def staging
-    calculate_metric(:staging,
+    @fetcher.calculate_metric(:staging,
                      MergeRequest::Metrics.arel_table[:merged_at],
                      MergeRequest::Metrics.arel_table[:first_deployed_to_production_at])
   end
 
   def production
-    calculate_metric(:production,
+    @fetcher.calculate_metric(:production,
                      Issue.arel_table[:created_at],
                      MergeRequest::Metrics.arel_table[:first_deployed_to_production_at])
   end
-
-  private
-
-  def calculate_metric(name, start_time_attrs, end_time_attrs)
-    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_for(name), end_time_attrs, start_time_attrs, name.to_s))
-
-    median_datetime(cte_table, interval_query, name)
-  end
-
-  # Join table with a row for every <issue,merge_request> pair (where the merge request
-  # closes the given issue) with issue and merge request metrics included. The metrics
-  # are loaded with an inner join, so issues / merge requests without metrics are
-  # automatically excluded.
-  def base_query_for(name)
-    arel_table = MergeRequestsClosingIssues.arel_table
-
-    # Load issues
-    query = arel_table.join(Issue.arel_table).on(Issue.arel_table[:id].eq(arel_table[:issue_id])).
-            join(Issue::Metrics.arel_table).on(Issue.arel_table[:id].eq(Issue::Metrics.arel_table[:issue_id])).
-            where(Issue.arel_table[:project_id].eq(@project.id)).
-            where(Issue.arel_table[:deleted_at].eq(nil)).
-            where(Issue.arel_table[:created_at].gteq(@from))
-
-    # Load merge_requests
-    query = query.join(MergeRequest.arel_table, Arel::Nodes::OuterJoin).
-            on(MergeRequest.arel_table[:id].eq(arel_table[:merge_request_id])).
-            join(MergeRequest::Metrics.arel_table).
-            on(MergeRequest.arel_table[:id].eq(MergeRequest::Metrics.arel_table[:merge_request_id]))
-
-    if DEPLOYMENT_METRIC_STAGES.include?(name)
-      # Limit to merge requests that have been deployed to production after `@from`
-      query.where(MergeRequest::Metrics.arel_table[:first_deployed_to_production_at].gteq(@from))
-    end
-
-    query
-  end
 end
diff --git a/app/models/merge_request/metrics.rb b/app/models/merge_request/metrics.rb
index 99c49a020c9..cdc408738be 100644
--- a/app/models/merge_request/metrics.rb
+++ b/app/models/merge_request/metrics.rb
@@ -1,5 +1,6 @@
 class MergeRequest::Metrics < ActiveRecord::Base
   belongs_to :merge_request
+  belongs_to :pipeline, class_name: 'Ci::Pipeline', foreign_key: :pipeline_id
 
   def record!
     if merge_request.merged? && self.merged_at.blank?