1 files changed, 176 insertions, 0 deletions
diff --git a/lib/gitlab/background_migration/migrate_events_to_push_event_payloads.rb b/lib/gitlab/background_migration/migrate_events_to_push_event_payloads.rb
new file mode 100644
index 00000000000..432f7c3e706
--- /dev/null
+++ b/lib/gitlab/background_migration/migrate_events_to_push_event_payloads.rb
@@ -0,0 +1,176 @@
+module Gitlab
+  module BackgroundMigration
+    # Class that migrates events for the new push event payloads setup. All
+    # events are copied to a shadow table, and push events will also have a row
+    # created in the push_event_payloads table.
+    class MigrateEventsToPushEventPayloads
+      class Event < ActiveRecord::Base
+        self.table_name = 'events'
+
+        serialize :data
+
+        BLANK_REF = ('0' * 40).freeze
+        TAG_REF_PREFIX = 'refs/tags/'.freeze
+        MAX_INDEX = 69
+        PUSHED = 5
+
+        def push_event?
+          action == PUSHED && data.present?
+        end
+
+        def commit_title
+          commit = commits.last
+
+          return nil unless commit && commit[:message]
+
+          index = commit[:message].index("\n")
+          message = index ? commit[:message][0..index] : commit[:message]
+
+          message.strip.truncate(70)
+        end
+
+        def commit_from_sha
+          if create?
+            nil
+          else
+            data[:before]
+          end
+        end
+
+        def commit_to_sha
+          if remove?
+            nil
+          else
+            data[:after]
+          end
+        end
+
+        def data
+          super || {}
+        end
+
+        def commits
+          data[:commits] || []
+        end
+
+        def commit_count
+          data[:total_commits_count] || 0
+        end
+
+        def ref
+          data[:ref]
+        end
+
+        def trimmed_ref_name
+          if ref_type == :tag
+            ref[10..-1]
+          else
+            ref[11..-1]
+          end
+        end
+
+        def create?
+          data[:before] == BLANK_REF
+        end
+
+        def remove?
+          data[:after] == BLANK_REF
+        end
+
+        def push_action
+          if create?
+            :created
+          elsif remove?
+            :removed
+          else
+            :pushed
+          end
+        end
+
+        def ref_type
+          if ref.start_with?(TAG_REF_PREFIX)
+            :tag
+          else
+            :branch
+          end
+        end
+      end
+
+      class EventForMigration < ActiveRecord::Base
+        self.table_name = 'events_for_migration'
+      end
+
+      class PushEventPayload < ActiveRecord::Base
+        self.table_name = 'push_event_payloads'
+
+        enum action: {
+          created: 0,
+          removed: 1,
+          pushed: 2
+        }
+
+        enum ref_type: {
+          branch: 0,
+          tag: 1
+        }
+      end
+
+      # start_id - The start ID of the range of events to process
+      # end_id - The end ID of the range to process.
+      def perform(start_id, end_id)
+        return unless migrate?
+
+        find_events(start_id, end_id).each { |event| process_event(event) }
+      end
+
+      def process_event(event)
+        replicate_event(event)
+        create_push_event_payload(event) if event.push_event?
+      end
+
+      def replicate_event(event)
+        new_attributes = event.attributes
+          .with_indifferent_access.except(:title, :data)
+
+        EventForMigration.create!(new_attributes)
+      rescue ActiveRecord::InvalidForeignKey
+        # A foreign key error means the associated event was removed. In this
+        # case we'll just skip migrating the event.
+      end
+
+      def create_push_event_payload(event)
+        commit_from = pack(event.commit_from_sha)
+        commit_to = pack(event.commit_to_sha)
+
+        PushEventPayload.create!(
+          event_id: event.id,
+          commit_count: event.commit_count,
+          ref_type: event.ref_type,
+          action: event.push_action,
+          commit_from: commit_from,
+          commit_to: commit_to,
+          ref: event.trimmed_ref_name,
+          commit_title: event.commit_title
+        )
+      rescue ActiveRecord::InvalidForeignKey
+        # A foreign key error means the associated event was removed. In this
+        # case we'll just skip migrating the event.
+      end
+
+      def find_events(start_id, end_id)
+        Event
+          .where('NOT EXISTS (SELECT true FROM events_for_migration WHERE events_for_migration.id = events.id)')
+          .where(id: start_id..end_id)
+      end
+
+      def migrate?
+        Event.table_exists? && PushEventPayload.table_exists? &&
+          EventForMigration.table_exists?
+      end
+
+      def pack(value)
+        value ? [value].pack('H*') : nil
+      end
+    end
+  end
+end