REFACTOR: Restoring of backups and migration of uploads to S3

lib/backup_restore/backup_file_handler.rb

@@ -0,0 +1,96 @@
+# frozen_string_literal: true
+
+module BackupRestore
+  class BackupFileHandler
+    OLD_DUMP_FILENAME = "dump.sql"
+
+    delegate :log, to: :@logger, private: true
+
+    def initialize(logger, filename, current_db, root_tmp_directory = Rails.root)
+      @logger = logger
+      @filename = filename
+      @current_db = current_db
+      @root_tmp_directory = root_tmp_directory
+      @is_archive = !(@filename =~ /\.sql\.gz$/)
+    end
+
+    def decompress
+      create_tmp_directory
+      @archive_path = File.join(@tmp_directory, @filename)
+
+      copy_archive_to_tmp_directory
+      decompress_archive
+      extract_db_dump
+
+      [@tmp_directory, @db_dump_path]
+    end
+
+    def clean_up
+      return if @tmp_directory.blank?
+
+      log "Removing tmp '#{@tmp_directory}' directory..."
+      FileUtils.rm_rf(@tmp_directory) if Dir[@tmp_directory].present?
+    rescue => ex
+      log "Something went wrong while removing the following tmp directory: #{@tmp_directory}", ex
+    end
+
+    protected
+
+    def create_tmp_directory
+      timestamp = Time.zone.now.strftime("%Y-%m-%d-%H%M%S")
+      @tmp_directory = File.join(@root_tmp_directory, "tmp", "restores", @current_db, timestamp)
+      ensure_directory_exists(@tmp_directory)
+    end
+
+    def ensure_directory_exists(directory)
+      log "Making sure #{directory} exists..."
+      FileUtils.mkdir_p(directory)
+    end
+
+    def copy_archive_to_tmp_directory
+      store = BackupRestore::BackupStore.create
+
+      if store.remote?
+        log "Downloading archive to tmp directory..."
+        failure_message = "Failed to download archive to tmp directory."
+      else
+        log "Copying archive to tmp directory..."
+        failure_message = "Failed to copy archive to tmp directory."
+      end
+
+      store.download_file(@filename, @archive_path, failure_message)
+    end
+
+    def decompress_archive
+      return if !@is_archive
+
+      log "Unzipping archive, this may take a while..."
+      pipeline = Compression::Pipeline.new([Compression::Tar.new, Compression::Gzip.new])
+      unzipped_path = pipeline.decompress(@tmp_directory, @archive_path, available_size)
+      pipeline.strip_directory(unzipped_path, @tmp_directory)
+    end
+
+    def extract_db_dump
+      @db_dump_path =
+        if @is_archive
+          # for compatibility with backups from Discourse v1.5 and below
+          old_dump_path = File.join(@tmp_directory, OLD_DUMP_FILENAME)
+          File.exists?(old_dump_path) ? old_dump_path : File.join(@tmp_directory, BackupRestore::DUMP_FILE)
+        else
+          File.join(@tmp_directory, @filename)
+        end
+
+      if File.extname(@db_dump_path) == '.gz'
+        log "Extracting dump file..."
+        Compression::Gzip.new.decompress(@tmp_directory, @db_dump_path, available_size)
+        @db_dump_path.delete_suffix!('.gz')
+      end
+
+      @db_dump_path
+    end
+
+    def available_size
+      SiteSetting.decompressed_backup_max_file_size_mb
+    end
+  end
+end