Backfill project_repositories for legacy storage projects

Adds a background migration that will ensure all projects that
are on legacy storage have a row in `project_repositories`.

3 files changed, 238 insertions, 123 deletions

diff --git a/lib/gitlab/background_migration/backfill_hashed_project_repositories.rb b/lib/gitlab/background_migration/backfill_hashed_project_repositories.rb
index 2f76f2f7434..a6194616663 100644
--- a/lib/gitlab/background_migration/backfill_hashed_project_repositories.rb
+++ b/lib/gitlab/background_migration/backfill_hashed_project_repositories.rb
@@ -2,132 +2,13 @@
 
 module Gitlab
   module BackgroundMigration
-    # Class that will create fill the project_repositories table
-    # for all projects that are on hashed storage and an entry is
-    # is missing in this table.
-    class BackfillHashedProjectRepositories
-      # Shard model
-      class Shard < ActiveRecord::Base
-        self.table_name = 'shards'
-      end
-
-      # Class that will find or create the shard by name.
-      # There is only a small set of shards, which would
-      # not change quickly, so look them up from memory
-      # instead of hitting the DB each time.
-      class ShardFinder
-        def find_shard_id(name)
-          shard_id = shards.fetch(name, nil)
-          return shard_id if shard_id.present?
-
-          Shard.transaction(requires_new: true) do
-            create!(name)
-          end
-        rescue ActiveRecord::RecordNotUnique
-          reload!
-          retry
-        end
-
-        private
-
-        def create!(name)
-          Shard.create!(name: name).tap { |shard| @shards[name] = shard.id }
-        end
-
-        def shards
-          @shards ||= reload!
-        end
-
-        def reload!
-          @shards = Hash[*Shard.all.map { |shard| [shard.name, shard.id] }.flatten]
-        end
-      end
-
-      # ProjectRegistry model
-      class ProjectRepository < ActiveRecord::Base
-        self.table_name = 'project_repositories'
-
-        belongs_to :project, inverse_of: :project_repository
-      end
-
-      # Project model
-      class Project < ActiveRecord::Base
-        self.table_name = 'projects'
-
-        HASHED_PATH_PREFIX = '@hashed'
-
-        HASHED_STORAGE_FEATURES = {
-          repository: 1,
-          attachments: 2
-        }.freeze
-
-        has_one :project_repository, inverse_of: :project
-
-        class << self
-          def on_hashed_storage
-            where(Project.arel_table[:storage_version]
-              .gteq(HASHED_STORAGE_FEATURES[:repository]))
-          end
-
-          def without_project_repository
-            joins(left_outer_join_project_repository)
-              .where(ProjectRepository.arel_table[:project_id].eq(nil))
-          end
-
-          def left_outer_join_project_repository
-            projects_table = Project.arel_table
-            repository_table = ProjectRepository.arel_table
-
-            projects_table
-              .join(repository_table, Arel::Nodes::OuterJoin)
-              .on(projects_table[:id].eq(repository_table[:project_id]))
-              .join_sources
-          end
-        end
-
-        def hashed_storage?
-          self.storage_version && self.storage_version >= 1
-        end
-
-        def hashed_disk_path
-          "#{HASHED_PATH_PREFIX}/#{disk_hash[0..1]}/#{disk_hash[2..3]}/#{disk_hash}"
-        end
-
-        def disk_hash
-          @disk_hash ||= Digest::SHA2.hexdigest(id.to_s)
-        end
-      end
-
-      def perform(start_id, stop_id)
-        Gitlab::Database.bulk_insert(:project_repositories, project_repositories(start_id, stop_id))
-      end
-
+    # Class that will fill the project_repositories table for projects that
+    # are on hashed storage and an entry is is missing in this table.
+    class BackfillHashedProjectRepositories < BackfillProjectRepositories
       private
 
-      def project_repositories(start_id, stop_id)
+      def projects
         Project.on_hashed_storage
-          .without_project_repository
-          .where(id: start_id..stop_id)
-          .map { |project| build_attributes_for_project(project) }
-          .compact
-      end
-
-      def build_attributes_for_project(project)
-        return unless project.hashed_storage?
-
-        {
-          project_id: project.id,
-          shard_id:   find_shard_id(project.repository_storage),
-          disk_path:  project.hashed_disk_path
-        }
-      end
-
-      def find_shard_id(repository_storage)
-        shard_finder.find_shard_id(repository_storage)
-      end
-
-      def shard_finder
-        @shard_finder ||= ShardFinder.new
       end
     end
   end
diff --git a/lib/gitlab/background_migration/backfill_legacy_project_repositories.rb b/lib/gitlab/background_migration/backfill_legacy_project_repositories.rb
new file mode 100644
index 00000000000..6dc92672929
--- /dev/null
+++ b/lib/gitlab/background_migration/backfill_legacy_project_repositories.rb
@@ -0,0 +1,15 @@
+# frozen_string_literal: true
+
+module Gitlab
+  module BackgroundMigration
+    # Class that will fill the project_repositories table for projects that
+    # are on legacy storage and an entry is is missing in this table.
+    class BackfillLegacyProjectRepositories < BackfillProjectRepositories
+      private
+
+      def projects
+        Project.with_parent.on_legacy_storage
+      end
+    end
+  end
+end
diff --git a/lib/gitlab/background_migration/backfill_project_repositories.rb b/lib/gitlab/background_migration/backfill_project_repositories.rb
new file mode 100644
index 00000000000..aaf520d70f6
--- /dev/null
+++ b/lib/gitlab/background_migration/backfill_project_repositories.rb
@@ -0,0 +1,219 @@
+# frozen_string_literal: true
+
+module Gitlab
+  module BackgroundMigration
+    # Class that will create fill the project_repositories table
+    # for projects an entry is is missing in this table.
+    class BackfillProjectRepositories
+      OrphanedNamespaceError = Class.new(StandardError)
+
+      # Shard model
+      class Shard < ActiveRecord::Base
+        self.table_name = 'shards'
+      end
+
+      # Class that will find or create the shard by name.
+      # There is only a small set of shards, which would
+      # not change quickly, so look them up from memory
+      # instead of hitting the DB each time.
+      class ShardFinder
+        def find_shard_id(name)
+          shard_id = shards.fetch(name, nil)
+          return shard_id if shard_id.present?
+
+          Shard.transaction(requires_new: true) do
+            create!(name)
+          end
+        rescue ActiveRecord::RecordNotUnique
+          reload!
+          retry
+        end
+
+        private
+
+        def create!(name)
+          Shard.create!(name: name).tap { |shard| @shards[name] = shard.id }
+        end
+
+        def shards
+          @shards ||= reload!
+        end
+
+        def reload!
+          @shards = Hash[*Shard.all.map { |shard| [shard.name, shard.id] }.flatten]
+        end
+      end
+
+      module Storage
+        # Class that returns the disk path for a project using hashed storage
+        class HashedProject
+          attr_accessor :project
+
+          ROOT_PATH_PREFIX = '@hashed'
+
+          def initialize(project)
+            @project = project
+          end
+
+          def disk_path
+            "#{ROOT_PATH_PREFIX}/#{disk_hash[0..1]}/#{disk_hash[2..3]}/#{disk_hash}"
+          end
+
+          def disk_hash
+            @disk_hash ||= Digest::SHA2.hexdigest(project.id.to_s)
+          end
+        end
+
+        # Class that returns the disk path for a project using legacy storage
+        class LegacyProject
+          attr_accessor :project
+
+          def initialize(project)
+            @project = project
+          end
+
+          def disk_path
+            project.full_path
+          end
+        end
+      end
+
+      # Concern used by Project and Namespace to determine the full route to the project
+      module Routable
+        extend ActiveSupport::Concern
+
+        def full_path
+          @full_path ||= build_full_path
+        end
+
+        def build_full_path
+          return path unless has_parent?
+
+          raise OrphanedNamespaceError if parent.nil?
+
+          parent.full_path + '/' + path
+        end
+
+        def has_parent?
+          read_attribute(association(:parent).reflection.foreign_key)
+        end
+      end
+
+      # Namespace model.
+      class Namespace < ActiveRecord::Base
+        self.table_name = 'namespaces'
+        self.inheritance_column = nil
+
+        include Routable
+
+        belongs_to :parent, class_name: 'Namespace', inverse_of: 'namespaces'
+
+        has_many :projects, inverse_of: :parent
+        has_many :namespaces, inverse_of: :parent
+      end
+
+      # ProjectRegistry model
+      class ProjectRepository < ActiveRecord::Base
+        self.table_name = 'project_repositories'
+
+        belongs_to :project, inverse_of: :project_repository
+      end
+
+      # Project model
+      class Project < ActiveRecord::Base
+        self.table_name = 'projects'
+
+        include Routable
+
+        HASHED_STORAGE_FEATURES = {
+          repository: 1,
+          attachments: 2
+        }.freeze
+
+        scope :with_parent, -> { includes(:parent) }
+
+        belongs_to :parent, class_name: 'Namespace', foreign_key: :namespace_id, inverse_of: 'projects'
+
+        has_one :project_repository, inverse_of: :project
+
+        delegate :disk_path, to: :storage
+
+        class << self
+          def on_hashed_storage
+            where(Project.arel_table[:storage_version]
+              .gteq(HASHED_STORAGE_FEATURES[:repository]))
+          end
+
+          def on_legacy_storage
+            where(Project.arel_table[:storage_version].eq(nil)
+              .or(Project.arel_table[:storage_version].eq(0)))
+          end
+
+          def without_project_repository
+            joins(left_outer_join_project_repository)
+              .where(ProjectRepository.arel_table[:project_id].eq(nil))
+          end
+
+          def left_outer_join_project_repository
+            projects_table = Project.arel_table
+            repository_table = ProjectRepository.arel_table
+
+            projects_table
+              .join(repository_table, Arel::Nodes::OuterJoin)
+              .on(projects_table[:id].eq(repository_table[:project_id]))
+              .join_sources
+          end
+        end
+
+        def storage
+          @storage ||=
+            if hashed_storage?
+              Storage::HashedProject.new(self)
+            else
+              Storage::LegacyProject.new(self)
+            end
+        end
+
+        def hashed_storage?
+          self.storage_version &&
+            self.storage_version >= HASHED_STORAGE_FEATURES[:repository]
+        end
+      end
+
+      def perform(start_id, stop_id)
+        Gitlab::Database.bulk_insert(:project_repositories, project_repositories(start_id, stop_id))
+      end
+
+      private
+
+      def projects
+        raise NotImplementedError,
+          "#{self.class} does not implement #{__method__}"
+      end
+
+      def project_repositories(start_id, stop_id)
+        projects
+          .without_project_repository
+          .where(id: start_id..stop_id)
+          .map { |project| build_attributes_for_project(project) }
+          .compact
+      end
+
+      def build_attributes_for_project(project)
+        {
+          project_id: project.id,
+          shard_id:   find_shard_id(project.repository_storage),
+          disk_path:  project.disk_path
+        }
+      end
+
+      def find_shard_id(repository_storage)
+        shard_finder.find_shard_id(repository_storage)
+      end
+
+      def shard_finder
+        @shard_finder ||= ShardFinder.new
+      end
+    end
+  end
+end