Remove CommonMetricsImporter patch

Remove CommonMetricsImporter patch and change all references to
CommonMetrics::Importer. Move specs into their appropriate folders. Also
cleans up some common_metric importer namespacing.

db/fixtures/development/99_common_metrics.rb

 # frozen_string_literal: true
 
-require Rails.root.join('db/importers/common_metrics_importer.rb')
-
-::Importers::CommonMetricsImporter.new.execute
+::Gitlab::Importers::CommonMetrics::Importer.new.execute

db/fixtures/production/999_common_metrics.rb

 # frozen_string_literal: true
 
-require Rails.root.join('db/importers/common_metrics_importer.rb')
-
-::Importers::CommonMetricsImporter.new.execute
+::Gitlab::Importers::CommonMetrics::Importer.new.execute

db/importers/common_metrics_importer.rb

-# This functionality has been moved to the lib/gitlab/importers/common_metrics module.
-# This is here only to preserve existing ::Importers::CommonMetricsImporter api
-module Importers
-  module CommonMetricsImporter
-    def self.new(*args)
-      Gitlab::Importers::CommonMetrics::Importer.new(*args)
-    end
-  end
-end

db/migrate/20180831164910_import_common_metrics.rb

@@ -3,12 +3,10 @@
 class ImportCommonMetrics < ActiveRecord::Migration[4.2]
   include Gitlab::Database::MigrationHelpers
 
-  require Rails.root.join('db/importers/common_metrics_importer.rb')
-
   DOWNTIME = false
 
   def up
-    Importers::CommonMetricsImporter.new.execute
+    ::Gitlab::Importers::CommonMetrics::Importer.new.execute
   end
 
   def down

db/migrate/20181006004100_import_common_metrics_nginx_vts.rb

 class ImportCommonMetricsNginxVts < ActiveRecord::Migration[5.0]
   include Gitlab::Database::MigrationHelpers
 
-  require Rails.root.join('db/importers/common_metrics_importer.rb')
-
   DOWNTIME = false
 
   def up
-    Importers::CommonMetricsImporter.new.execute
+    ::Gitlab::Importers::CommonMetrics::Importer.new.execute
   end
 
   def down

db/migrate/20190326164045_import_common_metrics_knative.rb

@@ -3,12 +3,10 @@
 class ImportCommonMetricsKnative < ActiveRecord::Migration[5.0]
   include Gitlab::Database::MigrationHelpers
 
-  require Rails.root.join('db/importers/common_metrics_importer.rb')
-
   DOWNTIME = false
 
   def up
-    Importers::CommonMetricsImporter.new.execute
+    ::Gitlab::Importers::CommonMetrics::Importer.new.execute
   end
 
   def down

db/migrate/20190408163745_prometheus_knative05_fix.rb

@@ -6,12 +6,10 @@
 class PrometheusKnative05Fix < ActiveRecord::Migration[5.0]
   include Gitlab::Database::MigrationHelpers
 
-  require Rails.root.join('db/importers/common_metrics_importer.rb')
-
   DOWNTIME = false
 
   def up
-    Importers::CommonMetricsImporter.new.execute
+    ::Gitlab::Importers::CommonMetrics::Importer.new.execute
   end
 
   def down

doc/development/prometheus_metrics.md

@@ -33,12 +33,10 @@ For example: you might be interested in migrating all dependent data to a differ
 class ImportCommonMetrics < ActiveRecord::Migration[4.2]
   include Gitlab::Database::MigrationHelpers
 
-  require Rails.root.join('db/importers/common_metrics_importer.rb')
-
   DOWNTIME = false
 
   def up
-    Importers::CommonMetricsImporter.new.execute
+    ::Gitlab::Importers::CommonMetrics::Importer.new.execute
   end
 
   def down

lib/gitlab/importers/common_metrics/importer.rb

@@ -13,7 +13,7 @@ module Gitlab
         end
 
         def execute
-          ::Gitlab::Importers::CommonMetrics::PrometheusMetric.reset_column_information
+          CommonMetrics::PrometheusMetric.reset_column_information
 
           process_content do |id, attributes|
             find_or_build_metric!(id)
@@ -62,17 +62,17 @@ module Gitlab
         def find_or_build_metric!(id)
           raise MissingQueryId unless id
 
-          ::Gitlab::Importers::CommonMetrics::PrometheusMetric.common.find_by(identifier: id) ||
-            ::Gitlab::Importers::CommonMetrics::PrometheusMetric.new(common: true, identifier: id)
+          CommonMetrics::PrometheusMetric.common.find_by(identifier: id) ||
+            CommonMetrics::PrometheusMetric.new(common: true, identifier: id)
         end
         # rubocop: enable CodeReuse/ActiveRecord
 
         def find_group_title_key(title)
-          ::Gitlab::Importers::CommonMetrics::PrometheusMetricEnums.groups[find_group_title(title)]
+          CommonMetrics::PrometheusMetricEnums.groups[find_group_title(title)]
         end
 
         def find_group_title(title)
-          ::Gitlab::Importers::CommonMetrics::PrometheusMetricEnums.group_titles.invert[title]
+          CommonMetrics::PrometheusMetricEnums.group_titles.invert[title]
         end
       end
     end

lib/gitlab/importers/common_metrics/prometheus_metric_enums.rb

@@ -38,3 +38,5 @@ module Gitlab
     end
   end
 end
+
+::Gitlab::Importers::CommonMetrics::PrometheusMetricEnums.prepend EE::Gitlab::Importers::CommonMetrics::PrometheusMetricEnums

spec/db/importers/common_metrics_importer_spec.rb → spec/lib/gitlab/importers/common_metrics/importer_spec.rb

 # frozen_string_literal: true
 
 require 'rails_helper'
-require Rails.root.join("db", "importers", "common_metrics_importer.rb")
 
-describe Gitlab::Importers::CommonMetrics::PrometheusMetric do
-  let(:existing_group_titles) do
-    ::PrometheusMetricEnums.group_details.each_with_object({}) do |(key, value), memo|
-      memo[key] = value[:group_title]
-    end
-  end
-
-  it 'group enum equals ::PrometheusMetric' do
-    expect(described_class.groups).to eq(::PrometheusMetric.groups)
-  end
-
-  it 'GROUP_TITLES equals ::PrometheusMetric' do
-    expect(Gitlab::Importers::CommonMetrics::PrometheusMetricEnums.group_titles).to eq(existing_group_titles)
-  end
-end
-
-describe Importers::CommonMetricsImporter do
+describe Gitlab::Importers::CommonMetrics::Importer do
   subject { described_class.new }
 
   context "does import common_metrics.yml" do

spec/lib/gitlab/importers/common_metrics/prometheus_metric_spec.rb

+# frozen_string_literal: true
+
+require 'rails_helper'
+
+describe Gitlab::Importers::CommonMetrics::PrometheusMetric do
+  let(:existing_group_titles) do
+    ::PrometheusMetricEnums.group_details.each_with_object({}) do |(key, value), memo|
+      memo[key] = value[:group_title]
+    end
+  end
+
+  it 'group enum equals ::PrometheusMetric' do
+    expect(described_class.groups).to eq(::PrometheusMetric.groups)
+  end
+
+  it '.group_titles equals ::PrometheusMetric' do
+    expect(Gitlab::Importers::CommonMetrics::PrometheusMetricEnums.group_titles).to eq(existing_group_titles)
+  end
+end