Address Rubocop offenses

lib/gitlab/background_migration/populate_untracked_uploads.rb

+# frozen_string_literal: true
+
 module Gitlab
   module BackgroundMigration
-    class PopulateUntrackedUploads
-      class UntrackedFile < ActiveRecord::Base
+    # This class processes a batch of rows in `untracked_files_for_uploads` by
+    # adding each file to the `uploads` table if it does not exist.
+    class PopulateUntrackedUploads # rubocop:disable Metrics/ClassLength
+      # This class is responsible for producing the attributes necessary to
+      # track an uploaded file in the `uploads` table.
+      class UntrackedFile < ActiveRecord::Base # rubocop:disable Metrics/ClassLength, Metrics/LineLength
         self.table_name = 'untracked_files_for_uploads'
 
         # Ends with /:random_hex/:filename
-        FILE_UPLOADER_PATH_PATTERN = %r{/\h+/[^/]+\z}
-        FILE_UPLOADER_CAPTURE_FULL_PATH_PATTERN = %r{\A(.+)#{FILE_UPLOADER_PATH_PATTERN}}
+        FILE_UPLOADER_PATH = %r{/\h+/[^/]+\z}
+        FULL_PATH_CAPTURE = %r{\A(.+)#{FILE_UPLOADER_PATH}}
 
         # These regex patterns are tested against a relative path, relative to
         # the upload directory.
@@ -44,7 +50,7 @@ module Gitlab
             model_type: 'Project'
           },
           {
-            pattern: FILE_UPLOADER_PATH_PATTERN,
+            pattern: FILE_UPLOADER_PATH,
             uploader: 'FileUploader',
             model_type: 'Project'
           }
@@ -63,9 +69,10 @@ module Gitlab
 
         def upload_path
           # UntrackedFile#path is absolute, but Upload#path depends on uploader
-          @upload_path ||= if uploader == 'FileUploader'
+          @upload_path ||=
+            if uploader == 'FileUploader'
               # Path relative to project directory in uploads
-                             matchd = path_relative_to_upload_dir.match(FILE_UPLOADER_PATH_PATTERN)
+              matchd = path_relative_to_upload_dir.match(FILE_UPLOADER_PATH)
               matchd[0].sub(%r{\A/}, '') # remove leading slash
             else
               path
@@ -83,7 +90,8 @@ module Gitlab
         def model_id
           return @model_id if defined?(@model_id)
 
-          matchd = path_relative_to_upload_dir.match(matching_pattern_map[:pattern])
+          pattern = matching_pattern_map[:pattern]
+          matchd = path_relative_to_upload_dir.match(pattern)
 
           # If something is captured (matchd[1] is not nil), it is a model_id
           # Only the FileUploader pattern will not match an ID
@@ -105,14 +113,20 @@ module Gitlab
             path_relative_to_upload_dir.match(path_pattern_map[:pattern])
           end
 
-          raise "Unknown upload path pattern \"#{path}\"" unless @matching_pattern_map
+          unless @matching_pattern_map
+            raise "Unknown upload path pattern \"#{path}\""
+          end
 
           @matching_pattern_map
         end
 
         def file_uploader_model_id
-          matchd = path_relative_to_upload_dir.match(FILE_UPLOADER_CAPTURE_FULL_PATH_PATTERN)
-          raise "Could not capture project full_path from a FileUploader path: \"#{path_relative_to_upload_dir}\"" unless matchd
+          matchd = path_relative_to_upload_dir.match(FULL_PATH_CAPTURE)
+          not_found_msg = <<~MSG
+            Could not capture project full_path from a FileUploader path:
+              "#{path_relative_to_upload_dir}"
+          MSG
+          raise not_found_msg unless matchd
 
           full_path = matchd[1]
           project = Project.find_by_full_path(full_path)
@@ -123,7 +137,8 @@ module Gitlab
 
         # Not including a leading slash
         def path_relative_to_upload_dir
-          base = %r{\A#{Regexp.escape(Gitlab::BackgroundMigration::PrepareUntrackedUploads::RELATIVE_UPLOAD_DIR)}/}
+          upload_dir = Gitlab::BackgroundMigration::PrepareUntrackedUploads::RELATIVE_UPLOAD_DIR # rubocop:disable Metrics/LineLength
+          base = %r{\A#{Regexp.escape(upload_dir)}/}
           @path_relative_to_upload_dir ||= path.sub(base, '')
         end
 
@@ -132,6 +147,7 @@ module Gitlab
         end
       end
 
+      # This class is used to query the `uploads` table.
       class Upload < ActiveRecord::Base
         self.table_name = 'uploads'
       end
@@ -192,8 +208,10 @@ module Gitlab
         end
 
         ids.each do |model_type, model_ids|
-          found_ids = Object.const_get(model_type).where(id: model_ids.uniq).pluck(:id)
-          ids[model_type] = ids[model_type] - found_ids # replace with deleted ids
+          model_class = Object.const_get(model_type)
+          found_ids = model_class.where(id: model_ids.uniq).pluck(:id)
+          deleted_ids = ids[model_type] - found_ids
+          ids[model_type] = deleted_ids
         end
 
         ids
@@ -204,11 +222,15 @@ module Gitlab
           file.to_h.merge(created_at: 'NOW()')
         end
 
-        Gitlab::Database.bulk_insert('uploads', rows, disable_quote: :created_at)
+        Gitlab::Database.bulk_insert('uploads',
+                                     rows,
+                                     disable_quote: :created_at)
       end
 
       def drop_temp_table_if_finished
-        UntrackedFile.connection.drop_table(:untracked_files_for_uploads) if UntrackedFile.all.empty?
+        if UntrackedFile.all.empty?
+          UntrackedFile.connection.drop_table(:untracked_files_for_uploads)
+        end
       end
     end
   end

lib/gitlab/background_migration/prepare_untracked_uploads.rb

+# frozen_string_literal: true
+
 module Gitlab
   module BackgroundMigration
-    class PrepareUntrackedUploads
+    # This class finds all non-hashed uploaded file paths and saves them to a
+    # `untracked_files_for_uploads` table.
+    class PrepareUntrackedUploads # rubocop:disable Metrics/ClassLength
       # For bulk_queue_background_migration_jobs_by_range
       include Database::MigrationHelpers
 
-      FILE_PATH_BATCH_SIZE = 500
+      FIND_BATCH_SIZE = 500
       RELATIVE_UPLOAD_DIR = "uploads".freeze
       ABSOLUTE_UPLOAD_DIR = "#{CarrierWave.root}/#{RELATIVE_UPLOAD_DIR}".freeze
       FOLLOW_UP_MIGRATION = 'PopulateUntrackedUploads'.freeze
@@ -12,6 +16,8 @@ module Gitlab
       EXCLUDED_HASHED_UPLOADS_PATH = "#{ABSOLUTE_UPLOAD_DIR}/@hashed/*".freeze
       EXCLUDED_TMP_UPLOADS_PATH = "#{ABSOLUTE_UPLOAD_DIR}/tmp/*".freeze
 
+      # This class is used to iterate over batches of
+      # `untracked_files_for_uploads` rows.
       class UntrackedFile < ActiveRecord::Base
         include EachBatch
 
@@ -39,8 +45,9 @@ module Gitlab
       private
 
       def ensure_temporary_tracking_table_exists
-        unless UntrackedFile.connection.table_exists?(:untracked_files_for_uploads)
-          UntrackedFile.connection.create_table :untracked_files_for_uploads do |t|
+        table_name = :untracked_files_for_uploads
+        unless UntrackedFile.connection.table_exists?(table_name)
+          UntrackedFile.connection.create_table table_name do |t|
             t.string :path, limit: 600, null: false
             t.index :path, unique: true
           end
@@ -54,7 +61,7 @@ module Gitlab
       def store_untracked_file_paths
         return unless Dir.exist?(ABSOLUTE_UPLOAD_DIR)
 
-        each_file_batch(ABSOLUTE_UPLOAD_DIR, FILE_PATH_BATCH_SIZE) do |file_paths|
+        each_file_batch(ABSOLUTE_UPLOAD_DIR, FIND_BATCH_SIZE) do |file_paths|
           insert_file_paths(file_paths)
         end
       end
@@ -85,12 +92,17 @@ module Gitlab
       end
 
       def build_find_command(search_dir)
-        cmd = %W[find #{search_dir} -type f ! ( -path #{EXCLUDED_HASHED_UPLOADS_PATH} -prune ) ! ( -path #{EXCLUDED_TMP_UPLOADS_PATH} -prune ) -print0]
+        cmd = %W[find #{search_dir}
+                 -type f
+                 ! ( -path #{EXCLUDED_HASHED_UPLOADS_PATH} -prune )
+                 ! ( -path #{EXCLUDED_TMP_UPLOADS_PATH} -prune )
+                 -print0]
 
         ionice = which_ionice
         cmd = %W[#{ionice} -c Idle] + cmd if ionice
 
-        Rails.logger.info "PrepareUntrackedUploads find command: \"#{cmd.join(' ')}\""
+        log_msg = "PrepareUntrackedUploads find command: \"#{cmd.join(' ')}\""
+        Rails.logger.info log_msg
 
         cmd
       end
@@ -98,25 +110,32 @@ module Gitlab
       def which_ionice
         Gitlab::Utils.which('ionice')
       rescue StandardError
-        # In this case, returning false is relatively safe, even though it isn't very nice
+        # In this case, returning false is relatively safe,
+        # even though it isn't very nice
         false
       end
 
       def insert_file_paths(file_paths)
-        sql = if postgresql_pre_9_5?
+        sql = insert_sql(file_paths)
+
+        ActiveRecord::Base.connection.execute(sql)
+      end
+
+      def insert_sql(file_paths)
+        if postgresql_pre_9_5?
           "INSERT INTO #{table_columns_and_values_for_insert(file_paths)};"
         elsif postgresql?
-                "INSERT INTO #{table_columns_and_values_for_insert(file_paths)} ON CONFLICT DO NOTHING;"
+          "INSERT INTO #{table_columns_and_values_for_insert(file_paths)}"\
+            " ON CONFLICT DO NOTHING;"
         else # MySQL
-                "INSERT IGNORE INTO #{table_columns_and_values_for_insert(file_paths)};"
+          "INSERT IGNORE INTO"\
+            " #{table_columns_and_values_for_insert(file_paths)};"
         end
-
-        ActiveRecord::Base.connection.execute(sql)
       end
 
       def table_columns_and_values_for_insert(file_paths)
         values = file_paths.map do |file_path|
-          ActiveRecord::Base.send(:sanitize_sql_array, ['(?)', file_path]) # rubocop:disable GitlabSecurity/PublicSend
+          ActiveRecord::Base.send(:sanitize_sql_array, ['(?)', file_path]) # rubocop:disable GitlabSecurity/PublicSend, Metrics/LineLength
         end.join(', ')
 
         "#{UntrackedFile.table_name} (path) VALUES #{values}"
@@ -131,11 +150,13 @@ module Gitlab
       end
 
       def postgresql_pre_9_5?
-        @postgresql_pre_9_5 ||= postgresql? && Gitlab::Database.version.to_f < 9.5
+        @postgresql_pre_9_5 ||= postgresql? &&
+          Gitlab::Database.version.to_f < 9.5
       end
 
       def schedule_populate_untracked_uploads_jobs
-        bulk_queue_background_migration_jobs_by_range(UntrackedFile, FOLLOW_UP_MIGRATION)
+        bulk_queue_background_migration_jobs_by_range(
+          UntrackedFile, FOLLOW_UP_MIGRATION)
       end
     end
   end