Added error classes for specific backup rake task

Add error class for backup rake tasks

Changelog: added

lib/backup.rb

@@ -2,4 +2,43 @@
 
 module Backup
   Error = Class.new(StandardError)
+
+  class FileBackupError < Backup::Error
+    attr_reader :app_files_dir, :backup_tarball
+
+    def initialize(app_files_dir, backup_tarball)
+      @app_files_dir = app_files_dir
+      @backup_tarball = backup_tarball
+    end
+
+    def message
+      "Failed to create compressed file '#{backup_tarball}' when trying to backup the following paths: '#{app_files_dir}'"
+    end
+  end
+
+  class RepositoryBackupError < Backup::Error
+    attr_reader :container, :backup_repos_path
+
+    def initialize(container, backup_repos_path)
+      @container = container
+      @backup_repos_path = backup_repos_path
+    end
+
+    def message
+      "Failed to create compressed file '#{backup_repos_path}' when trying to backup the following paths: '#{container.disk_path}'"
+    end
+  end
+
+  class DatabaseBackupError < Backup::Error
+    attr_reader :config, :db_file_name
+
+    def initialize(config, db_file_name)
+      @config = config
+      @db_file_name = db_file_name
+    end
+
+    def message
+      "Failed to create compressed file '#{db_file_name}' when trying to backup the main database:\n - host: '#{config[:host]}'\n - port: '#{config[:port]}'\n - database: '#{config[:database]}'"
+    end
+  end
 end

spec/lib/backup/database_backup_error_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe Backup::DatabaseBackupError do
+  let(:config) do
+    {
+      host: 'localhost',
+      port: 5432,
+      database: 'gitlabhq_test'
+    }
+  end
+
+  let(:db_file_name) { File.join(Gitlab.config.backup.path, 'db', 'database.sql.gz') }
+
+  subject { described_class.new(config, db_file_name) }
+
+  it { is_expected.to respond_to :config }
+  it { is_expected.to respond_to :db_file_name }
+
+  it 'expects exception message to include database file' do
+    expect(subject.message).to include("#{db_file_name}")
+  end
+
+  it 'expects exception message to include database paths being back-up' do
+    expect(subject.message).to include("#{config[:host]}")
+    expect(subject.message).to include("#{config[:port]}")
+    expect(subject.message).to include("#{config[:database]}")
+  end
+end

spec/lib/backup/file_backup_error_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe Backup::FileBackupError do
+  let_it_be(:lfs) { create(:lfs_object) }
+  let_it_be(:upload) { create(:upload) }
+
+  let(:backup_tarball) { '/tmp/backup/uploads' }
+
+  shared_examples 'includes backup path' do
+    it { is_expected.to respond_to :app_files_dir }
+    it { is_expected.to respond_to :backup_tarball }
+
+    it 'expects exception message to include file backup path location' do
+      expect(subject.message).to include("#{subject.backup_tarball}")
+    end
+
+    it 'expects exception message to include file being back-up' do
+      expect(subject.message).to include("#{subject.app_files_dir}")
+    end
+  end
+
+  context 'with lfs file' do
+    subject { described_class.new(lfs, backup_tarball) }
+
+    it_behaves_like 'includes backup path'
+  end
+
+  context 'with uploads file' do
+    subject { described_class.new(upload, backup_tarball) }
+
+    it_behaves_like 'includes backup path'
+  end
+end

spec/lib/backup/repository_backup_error_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe Backup::RepositoryBackupError do
+  let_it_be(:snippet) { create(:snippet, content: 'foo', file_name: 'foo') }
+  let_it_be(:project) { create(:project, :repository) }
+  let_it_be(:wiki) { ProjectWiki.new(project, nil ) }
+
+  let(:backup_repos_path) { '/tmp/backup/repositories' }
+
+  shared_examples 'includes backup path' do
+    it { is_expected.to respond_to :container }
+    it { is_expected.to respond_to :backup_repos_path }
+
+    it 'expects exception message to include repo backup path location' do
+      expect(subject.message).to include("#{subject.backup_repos_path}")
+    end
+
+    it 'expects exception message to include container being back-up' do
+      expect(subject.message).to include("#{subject.container.disk_path}")
+    end
+  end
+
+  context 'with snippet repository' do
+    subject { described_class.new(snippet, backup_repos_path) }
+
+    it_behaves_like 'includes backup path'
+  end
+
+  context 'with project repository' do
+    subject { described_class.new(project, backup_repos_path) }
+
+    it_behaves_like 'includes backup path'
+  end
+
+  context 'with wiki repository' do
+    subject { described_class.new(wiki, backup_repos_path) }
+
+    it_behaves_like 'includes backup path'
+  end
+end