16 files changed, 517 insertions, 0 deletions
diff --git a/lib/gitlab/cycle_analytics/base_event.rb b/lib/gitlab/cycle_analytics/base_event.rb
new file mode 100644
index 00000000000..53a148ad703
--- /dev/null
+++ b/lib/gitlab/cycle_analytics/base_event.rb
@@ -0,0 +1,57 @@
+module Gitlab
+  module CycleAnalytics
+    class BaseEvent
+      include MetricsTables
+
+      attr_reader :stage, :start_time_attrs, :end_time_attrs, :projections, :query
+
+      def initialize(project:, options:)
+        @query = EventsQuery.new(project: project, options: options)
+        @project = project
+        @options = options
+      end
+
+      def fetch
+        update_author!
+
+        event_result.map do |event|
+          serialize(event) if has_permission?(event['id'])
+        end.compact
+      end
+
+      def custom_query(_base_query); end
+
+      def order
+        @order || @start_time_attrs
+      end
+
+      private
+
+      def update_author!
+        return unless event_result.any? && event_result.first['author_id']
+
+        Updater.update!(event_result, from: 'author_id', to: 'author', klass: User)
+      end
+
+      def event_result
+        @event_result ||= @query.execute(self).to_a
+      end
+
+      def serialize(_event)
+        raise NotImplementedError.new("Expected #{self.name} to implement serialize(event)")
+      end
+
+      def has_permission?(id)
+        allowed_ids.nil? || allowed_ids.include?(id.to_i)
+      end
+
+      def allowed_ids
+        nil
+      end
+
+      def event_result_ids
+        event_result.map { |event| event['id'] }
+      end
+    end
+  end
+end
diff --git a/lib/gitlab/cycle_analytics/code_event.rb b/lib/gitlab/cycle_analytics/code_event.rb
new file mode 100644
index 00000000000..2afdf0b8518
--- /dev/null
+++ b/lib/gitlab/cycle_analytics/code_event.rb
@@ -0,0 +1,28 @@
+module Gitlab
+  module CycleAnalytics
+    class CodeEvent < BaseEvent
+      include MergeRequestAllowed
+
+      def initialize(*args)
+        @stage = :code
+        @start_time_attrs = issue_metrics_table[:first_mentioned_in_commit_at]
+        @end_time_attrs = mr_table[:created_at]
+        @projections = [mr_table[:title],
+                        mr_table[:iid],
+                        mr_table[:id],
+                        mr_table[:created_at],
+                        mr_table[:state],
+                        mr_table[:author_id]]
+        @order = mr_table[:created_at]
+
+        super(*args)
+      end
+
+      private
+
+      def serialize(event)
+        AnalyticsMergeRequestSerializer.new(project: @project).represent(event).as_json
+      end
+    end
+  end
+end
diff --git a/lib/gitlab/cycle_analytics/events.rb b/lib/gitlab/cycle_analytics/events.rb
new file mode 100644
index 00000000000..2d703d76cbb
--- /dev/null
+++ b/lib/gitlab/cycle_analytics/events.rb
@@ -0,0 +1,38 @@
+module Gitlab
+  module CycleAnalytics
+    class Events
+      def initialize(project:, options:)
+        @project = project
+        @options = options
+      end
+
+      def issue_events
+        IssueEvent.new(project: @project, options: @options).fetch
+      end
+
+      def plan_events
+        PlanEvent.new(project: @project, options: @options).fetch
+      end
+
+      def code_events
+        CodeEvent.new(project: @project, options: @options).fetch
+      end
+
+      def test_events
+        TestEvent.new(project: @project, options: @options).fetch
+      end
+
+      def review_events
+        ReviewEvent.new(project: @project, options: @options).fetch
+      end
+
+      def staging_events
+        StagingEvent.new(project: @project, options: @options).fetch
+      end
+
+      def production_events
+        ProductionEvent.new(project: @project, options: @options).fetch
+      end
+    end
+  end
+end
diff --git a/lib/gitlab/cycle_analytics/events_query.rb b/lib/gitlab/cycle_analytics/events_query.rb
new file mode 100644
index 00000000000..2418832ccc2
--- /dev/null
+++ b/lib/gitlab/cycle_analytics/events_query.rb
@@ -0,0 +1,37 @@
+module Gitlab
+  module CycleAnalytics
+    class EventsQuery
+      attr_reader :project
+
+      def initialize(project:, options: {})
+        @project = project
+        @from = options[:from]
+        @branch = options[:branch]
+        @fetcher = Gitlab::CycleAnalytics::MetricsFetcher.new(project: project, from: @from, branch: @branch)
+      end
+
+      def execute(stage_class)
+        @stage_class = stage_class
+
+        ActiveRecord::Base.connection.exec_query(query.to_sql)
+      end
+
+      private
+
+      def query
+        base_query = @fetcher.base_query_for(@stage_class.stage)
+        diff_fn = @fetcher.subtract_datetimes_diff(base_query, @stage_class.start_time_attrs, @stage_class.end_time_attrs)
+
+        @stage_class.custom_query(base_query)
+
+        base_query.project(extract_epoch(diff_fn).as('total_time'), *@stage_class.projections).order(@stage_class.order.desc)
+      end
+
+      def extract_epoch(arel_attribute)
+        return arel_attribute unless Gitlab::Database.postgresql?
+
+        Arel.sql(%Q{EXTRACT(EPOCH FROM (#{arel_attribute.to_sql}))})
+      end
+    end
+  end
+end
diff --git a/lib/gitlab/cycle_analytics/issue_allowed.rb b/lib/gitlab/cycle_analytics/issue_allowed.rb
new file mode 100644
index 00000000000..a7652a70641
--- /dev/null
+++ b/lib/gitlab/cycle_analytics/issue_allowed.rb
@@ -0,0 +1,9 @@
+module Gitlab
+  module CycleAnalytics
+    module IssueAllowed
+      def allowed_ids
+        @allowed_ids ||= IssuesFinder.new(@options[:current_user], project_id: @project.id).execute.where(id: event_result_ids).pluck(:id)
+      end
+    end
+  end
+end
diff --git a/lib/gitlab/cycle_analytics/issue_event.rb b/lib/gitlab/cycle_analytics/issue_event.rb
new file mode 100644
index 00000000000..705b7e5ce24
--- /dev/null
+++ b/lib/gitlab/cycle_analytics/issue_event.rb
@@ -0,0 +1,27 @@
+module Gitlab
+  module CycleAnalytics
+    class IssueEvent < BaseEvent
+      include IssueAllowed
+
+      def initialize(*args)
+        @stage = :issue
+        @start_time_attrs = issue_table[:created_at]
+        @end_time_attrs = [issue_metrics_table[:first_associated_with_milestone_at],
+                           issue_metrics_table[:first_added_to_board_at]]
+        @projections = [issue_table[:title],
+                        issue_table[:iid],
+                        issue_table[:id],
+                        issue_table[:created_at],
+                        issue_table[:author_id]]
+
+        super(*args)
+      end
+
+      private
+
+      def serialize(event)
+        AnalyticsIssueSerializer.new(project: @project).represent(event).as_json
+      end
+    end
+  end
+end
diff --git a/lib/gitlab/cycle_analytics/merge_request_allowed.rb b/lib/gitlab/cycle_analytics/merge_request_allowed.rb
new file mode 100644
index 00000000000..28f6db44759
--- /dev/null
+++ b/lib/gitlab/cycle_analytics/merge_request_allowed.rb
@@ -0,0 +1,9 @@
+module Gitlab
+  module CycleAnalytics
+    module MergeRequestAllowed
+      def allowed_ids
+        @allowed_ids ||= MergeRequestsFinder.new(@options[:current_user], project_id: @project.id).execute.where(id: event_result_ids).pluck(:id)
+      end
+    end
+  end
+end
diff --git a/lib/gitlab/cycle_analytics/metrics_fetcher.rb b/lib/gitlab/cycle_analytics/metrics_fetcher.rb
new file mode 100644
index 00000000000..b71e8735e27
--- /dev/null
+++ b/lib/gitlab/cycle_analytics/metrics_fetcher.rb
@@ -0,0 +1,60 @@
+module Gitlab
+  module CycleAnalytics
+    class MetricsFetcher
+      include Gitlab::Database::Median
+      include Gitlab::Database::DateTime
+      include MetricsTables
+
+      DEPLOYMENT_METRIC_STAGES = %i[production staging]
+
+      def initialize(project:, from:, branch:)
+        @project = project
+        @project = project
+        @from = from
+        @branch = branch
+      end
+
+      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), start_time_attrs, end_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)
+        # Load issues
+        query = mr_closing_issues_table.join(issue_table).on(issue_table[:id].eq(mr_closing_issues_table[:issue_id])).
+          join(issue_metrics_table).on(issue_table[:id].eq(issue_metrics_table[:issue_id])).
+          where(issue_table[:project_id].eq(@project.id)).
+          where(issue_table[:deleted_at].eq(nil)).
+          where(issue_table[:created_at].gteq(@from))
+
+        query = query.where(build_table[:ref].eq(@branch)) if name == :test && @branch
+
+        # Load merge_requests
+        query = query.join(mr_table, Arel::Nodes::OuterJoin).
+          on(mr_table[:id].eq(mr_closing_issues_table[:merge_request_id])).
+          join(mr_metrics_table).
+          on(mr_table[:id].eq(mr_metrics_table[:merge_request_id]))
+
+        if DEPLOYMENT_METRIC_STAGES.include?(name)
+          # Limit to merge requests that have been deployed to production after `@from`
+          query.where(mr_metrics_table[:first_deployed_to_production_at].gteq(@from))
+        end
+
+        query
+      end
+    end
+  end
+end
diff --git a/lib/gitlab/cycle_analytics/metrics_tables.rb b/lib/gitlab/cycle_analytics/metrics_tables.rb
new file mode 100644
index 00000000000..9d25ef078e8
--- /dev/null
+++ b/lib/gitlab/cycle_analytics/metrics_tables.rb
@@ -0,0 +1,37 @@
+module Gitlab
+  module CycleAnalytics
+    module MetricsTables
+      def mr_metrics_table
+        MergeRequest::Metrics.arel_table
+      end
+
+      def mr_table
+        MergeRequest.arel_table
+      end
+
+      def mr_diff_table
+        MergeRequestDiff.arel_table
+      end
+
+      def mr_closing_issues_table
+        MergeRequestsClosingIssues.arel_table
+      end
+
+      def issue_table
+        Issue.arel_table
+      end
+
+      def issue_metrics_table
+        Issue::Metrics.arel_table
+      end
+
+      def user_table
+        User.arel_table
+      end
+
+      def build_table
+        ::CommitStatus.arel_table
+      end
+    end
+  end
+end
diff --git a/lib/gitlab/cycle_analytics/permissions.rb b/lib/gitlab/cycle_analytics/permissions.rb
new file mode 100644
index 00000000000..bef3b95ff1b
--- /dev/null
+++ b/lib/gitlab/cycle_analytics/permissions.rb
@@ -0,0 +1,44 @@
+module Gitlab
+  module CycleAnalytics
+    class Permissions
+      STAGE_PERMISSIONS = {
+        issue: :read_issue,
+        code: :read_merge_request,
+        test: :read_build,
+        review: :read_merge_request,
+        staging: :read_build,
+        production: :read_issue,
+      }.freeze
+
+      def self.get(*args)
+        new(*args).get
+      end
+
+      def initialize(user:, project:)
+        @user = user
+        @project = project
+        @stage_permission_hash = {}
+      end
+
+      def get
+        ::CycleAnalytics::STAGES.each do |stage|
+          @stage_permission_hash[stage] = authorized_stage?(stage)
+        end
+
+        @stage_permission_hash
+      end
+
+      private
+
+      def authorized_stage?(stage)
+        return false unless authorize_project(:read_cycle_analytics)
+
+        STAGE_PERMISSIONS[stage] ? authorize_project(STAGE_PERMISSIONS[stage]) : true
+      end
+
+      def authorize_project(permission)
+        Ability.allowed?(@user, permission, @project)
+      end
+    end
+  end
+end
diff --git a/lib/gitlab/cycle_analytics/plan_event.rb b/lib/gitlab/cycle_analytics/plan_event.rb
new file mode 100644
index 00000000000..7c3f0e9989f
--- /dev/null
+++ b/lib/gitlab/cycle_analytics/plan_event.rb
@@ -0,0 +1,46 @@
+module Gitlab
+  module CycleAnalytics
+    class PlanEvent < BaseEvent
+      def initialize(*args)
+        @stage = :plan
+        @start_time_attrs = issue_metrics_table[:first_associated_with_milestone_at]
+        @end_time_attrs = [issue_metrics_table[:first_added_to_board_at],
+                           issue_metrics_table[:first_mentioned_in_commit_at]]
+        @projections = [mr_diff_table[:st_commits].as('commits'),
+                        issue_metrics_table[:first_mentioned_in_commit_at]]
+
+        super(*args)
+      end
+
+      def custom_query(base_query)
+        base_query.join(mr_diff_table).on(mr_diff_table[:merge_request_id].eq(mr_table[:id]))
+      end
+
+      private
+
+      def serialize(event)
+        st_commit = first_time_reference_commit(event.delete('commits'), event)
+
+        return unless st_commit
+
+        serialize_commit(event, st_commit, query)
+      end
+
+      def first_time_reference_commit(commits, event)
+        return nil if commits.blank?
+
+        YAML.load(commits).find do |commit|
+          next unless commit[:committed_date] && event['first_mentioned_in_commit_at']
+
+          commit[:committed_date].to_i == DateTime.parse(event['first_mentioned_in_commit_at'].to_s).to_i
+        end
+      end
+
+      def serialize_commit(event, st_commit, query)
+        commit = Commit.new(Gitlab::Git::Commit.new(st_commit), @project)
+
+        AnalyticsCommitSerializer.new(project: @project, total_time: event['total_time']).represent(commit).as_json
+      end
+    end
+  end
+end
diff --git a/lib/gitlab/cycle_analytics/production_event.rb b/lib/gitlab/cycle_analytics/production_event.rb
new file mode 100644
index 00000000000..4868c3c6237
--- /dev/null
+++ b/lib/gitlab/cycle_analytics/production_event.rb
@@ -0,0 +1,26 @@
+module Gitlab
+  module CycleAnalytics
+    class ProductionEvent < BaseEvent
+      include IssueAllowed
+
+      def initialize(*args)
+        @stage = :production
+        @start_time_attrs = issue_table[:created_at]
+        @end_time_attrs = mr_metrics_table[:first_deployed_to_production_at]
+        @projections = [issue_table[:title],
+                        issue_table[:iid],
+                        issue_table[:id],
+                        issue_table[:created_at],
+                        issue_table[:author_id]]
+
+        super(*args)
+      end
+
+      private
+
+      def serialize(event)
+        AnalyticsIssueSerializer.new(project: @project).represent(event).as_json
+      end
+    end
+  end
+end
diff --git a/lib/gitlab/cycle_analytics/review_event.rb b/lib/gitlab/cycle_analytics/review_event.rb
new file mode 100644
index 00000000000..b394a02cc52
--- /dev/null
+++ b/lib/gitlab/cycle_analytics/review_event.rb
@@ -0,0 +1,25 @@
+module Gitlab
+  module CycleAnalytics
+    class ReviewEvent < BaseEvent
+      include MergeRequestAllowed
+
+      def initialize(*args)
+        @stage = :review
+        @start_time_attrs = mr_table[:created_at]
+        @end_time_attrs = mr_metrics_table[:merged_at]
+        @projections = [mr_table[:title],
+                        mr_table[:iid],
+                        mr_table[:id],
+                        mr_table[:created_at],
+                        mr_table[:state],
+                        mr_table[:author_id]]
+
+        super(*args)
+      end
+
+      def serialize(event)
+        AnalyticsMergeRequestSerializer.new(project: @project).represent(event).as_json
+      end
+    end
+  end
+end
diff --git a/lib/gitlab/cycle_analytics/staging_event.rb b/lib/gitlab/cycle_analytics/staging_event.rb
new file mode 100644
index 00000000000..a1f30b716f6
--- /dev/null
+++ b/lib/gitlab/cycle_analytics/staging_event.rb
@@ -0,0 +1,31 @@
+module Gitlab
+  module CycleAnalytics
+    class StagingEvent < BaseEvent
+      def initialize(*args)
+        @stage = :staging
+        @start_time_attrs = mr_metrics_table[:merged_at]
+        @end_time_attrs = mr_metrics_table[:first_deployed_to_production_at]
+        @projections = [build_table[:id]]
+        @order = build_table[:created_at]
+
+        super(*args)
+      end
+
+      def fetch
+        Updater.update!(event_result, from: 'id', to: 'build', klass: ::Ci::Build)
+
+        super
+      end
+
+      def custom_query(base_query)
+        base_query.join(build_table).on(mr_metrics_table[:pipeline_id].eq(build_table[:commit_id]))
+      end
+
+      private
+
+      def serialize(event)
+        AnalyticsBuildSerializer.new.represent(event['build']).as_json
+      end
+    end
+  end
+end
diff --git a/lib/gitlab/cycle_analytics/test_event.rb b/lib/gitlab/cycle_analytics/test_event.rb
new file mode 100644
index 00000000000..d553d0b5aec
--- /dev/null
+++ b/lib/gitlab/cycle_analytics/test_event.rb
@@ -0,0 +1,13 @@
+module Gitlab
+  module CycleAnalytics
+    class TestEvent < StagingEvent
+      def initialize(*args)
+        super(*args)
+
+        @stage = :test
+        @start_time_attrs =  mr_metrics_table[:latest_build_started_at]
+        @end_time_attrs = mr_metrics_table[:latest_build_finished_at]
+      end
+    end
+  end
+end
diff --git a/lib/gitlab/cycle_analytics/updater.rb b/lib/gitlab/cycle_analytics/updater.rb
new file mode 100644
index 00000000000..953268ebd46
--- /dev/null
+++ b/lib/gitlab/cycle_analytics/updater.rb
@@ -0,0 +1,30 @@
+module Gitlab
+  module CycleAnalytics
+    class Updater
+      def self.update!(*args)
+        new(*args).update!
+      end
+
+      def initialize(event_result, from:, to:, klass:)
+        @event_result = event_result
+        @klass = klass
+        @from = from
+        @to = to
+      end
+
+      def update!
+        @event_result.each do |event|
+          event[@to] = items[event.delete(@from).to_i].first
+        end
+      end
+
+      def result_ids
+        @event_result.map { |event| event[@from] }
+      end
+
+      def items
+        @items ||= @klass.find(result_ids).group_by { |item| item['id'] }
+      end
+    end
+  end
+end