polish the error handling when object storage is unavailable

app/workers/pseudonymizer_worker.rb

@@ -4,7 +4,7 @@ class PseudonymizerWorker
 
   def perform
     abort "The pseudonymizer is not available with this license." unless License.feature_available?(:pseudonymizer)
-    return unless Gitlab::CurrentSettings.pseudonymizer_enabled?
+    abort "The pseudonymizer is disabled." unless Gitlab::CurrentSettings.pseudonymizer_enabled?
 
     options = Pseudonymizer::Options.new(
       config: YAML.load_file(Gitlab.config.pseudonymizer.manifest),
@@ -14,6 +14,8 @@ class PseudonymizerWorker
     dumper = Pseudonymizer::Dumper.new(options)
     uploader = Pseudonymizer::Uploader.new(options, progress_output: File.open(File::NULL, "w"))
 
+    abort "The pseudonymizer object storage must be configured." unless uploader.available?
+
     begin
       dumper.tables_to_csv
       uploader.upload

lib/pseudonymizer/uploader.rb

 module Pseudonymizer
+  ObjectStorageUnavailableError = Class.new(StandardError)
+
   class Uploader
     include Gitlab::Utils::StrongMemoize
 
@@ -22,12 +24,20 @@ module Pseudonymizer
       @connection_params = self.class.object_store_credentials
     end
 
+    def available?
+      !connect_to_remote_directory.nil?
+    rescue ObjectStorageUnavailableError
+      false
+    end
+
     def upload
       progress_output.puts "Uploading output files to remote storage #{remote_directory}:"
 
       file_list.each do |file|
         upload_file(file, remote_directory)
       end
+    rescue ObjectStorageUnavailableError
+      abort "Cannot upload files, make sure the `pseudonimizer.upload.connection` is set properly".color(:red)
     end
 
     def cleanup
@@ -62,7 +72,8 @@ module Pseudonymizer
 
     def connect_to_remote_directory
       if @connection_params.blank?
-        abort "Cannot upload files, make sure the `pseudonimizer.upload.connection` is set properly".color(:red)
+        raise ObjectStorageUnavailableError
+
       end
 
       connection = ::Fog::Storage.new(@connection_params)

lib/tasks/gitlab/db.rake

@@ -83,6 +83,8 @@ namespace :gitlab do
       dumper = Pseudonymizer::Dumper.new(options)
       uploader = Pseudonymizer::Uploader.new(options)
 
+      abort "There is an error in the pseudonymizer object store configuration." unless uploader.available?
+
       begin
         dumper.tables_to_csv
         uploader.upload

spec/lib/pseudonymizer/pager_spec.rb

 require 'spec_helper'
 
 describe Pseudonymizer::Pager do
-  class Counter
-    @count = 0
-
-    def increment(*args)
-      self.count += 1
-    end
-  end
-
   let(:page_size) { 1 }
   let!(:projects) { create_list(:project, 10) }
   subject { described_class.new("projects", whitelisted_columns) }