Migrate group milestones when using Bulk Import

- Add group milestones relation to Group Migration tool
  in order to provide closer feature parity to Group
  Import/Export

changelogs/unreleased/georgekoltsov-bulk-import-migrate-milestones.yml

+---
+title: Migrate group milestones when using Bulk Import
+merge_request: 55981
+author:
+type: added

doc/user/group/import/index.md

@@ -49,6 +49,14 @@ The following resources are migrated to the target instance:
   - parent epic ([Introduced in 13.9](https://gitlab.com/gitlab-org/gitlab/-/issues/297459))
   - emoji award ([Introduced in 13.9](https://gitlab.com/gitlab-org/gitlab/-/issues/297466))
   - events ([Introduced in 13.10](https://gitlab.com/gitlab-org/gitlab/-/issues/297465))
+- Milestones ([Introduced in 13.10](https://gitlab.com/gitlab-org/gitlab/-/issues/292427))
+  - title
+  - description
+  - state (active / closed)
+  - start date
+  - due date
+  - created at
+  - updated at
 
 Any other items are **not** migrated.
 

ee/spec/lib/ee/bulk_imports/importers/group_importer_spec.rb

@@ -22,6 +22,7 @@ RSpec.describe BulkImports::Importers::GroupImporter do
       expect_to_run_pipeline BulkImports::Groups::Pipelines::SubgroupEntitiesPipeline, context: context
       expect_to_run_pipeline BulkImports::Groups::Pipelines::MembersPipeline, context: context
       expect_to_run_pipeline BulkImports::Groups::Pipelines::LabelsPipeline, context: context
+      expect_to_run_pipeline BulkImports::Groups::Pipelines::MilestonesPipeline, context: context
       expect_to_run_pipeline EE::BulkImports::Groups::Pipelines::EpicsPipeline, context: context
       expect_to_run_pipeline EE::BulkImports::Groups::Pipelines::EpicAwardEmojiPipeline, context: context
 

lib/bulk_imports/groups/graphql/get_milestones_query.rb

+# frozen_string_literal: true
+
+module BulkImports
+  module Groups
+    module Graphql
+      module GetMilestonesQuery
+        extend self
+
+        def to_s
+          <<-'GRAPHQL'
+          query ($full_path: ID!, $cursor: String) {
+            group(fullPath: $full_path) {
+              milestones(first: 100, after: $cursor, includeDescendants: false) {
+                page_info: pageInfo {
+                  end_cursor: endCursor
+                  has_next_page: hasNextPage
+                }
+                nodes {
+                  title
+                  description
+                  state
+                  start_date: startDate
+                  due_date: dueDate
+                  created_at: createdAt
+                  updated_at: updatedAt
+                }
+              }
+            }
+          }
+          GRAPHQL
+        end
+
+        def variables(context)
+          {
+            full_path: context.entity.source_full_path,
+            cursor: context.entity.next_page_for(:milestones)
+          }
+        end
+
+        def base_path
+          %w[data group milestones]
+        end
+
+        def data_path
+          base_path << 'nodes'
+        end
+
+        def page_info_path
+          base_path << 'page_info'
+        end
+      end
+    end
+  end
+end

lib/bulk_imports/groups/pipelines/milestones_pipeline.rb

+# frozen_string_literal: true
+
+module BulkImports
+  module Groups
+    module Pipelines
+      class MilestonesPipeline
+        include Pipeline
+
+        extractor BulkImports::Common::Extractors::GraphqlExtractor,
+          query: BulkImports::Groups::Graphql::GetMilestonesQuery
+
+        transformer Common::Transformers::ProhibitedAttributesTransformer
+
+        def load(context, data)
+          return unless data
+
+          raise ::BulkImports::Pipeline::NotAllowedError unless authorized?
+
+          context.group.milestones.create!(data)
+        end
+
+        def after_run(extracted_data)
+          context.entity.update_tracker_for(
+            relation: :milestones,
+            has_next_page: extracted_data.has_next_page?,
+            next_page: extracted_data.next_page
+          )
+
+          if extracted_data.has_next_page?
+            run
+          end
+        end
+
+        private
+
+        def authorized?
+          context.current_user.can?(:admin_milestone, context.group)
+        end
+      end
+    end
+  end
+end

lib/bulk_imports/importers/group_importer.rb

@@ -24,7 +24,8 @@ module BulkImports
           BulkImports::Groups::Pipelines::GroupPipeline,
           BulkImports::Groups::Pipelines::SubgroupEntitiesPipeline,
           BulkImports::Groups::Pipelines::MembersPipeline,
-          BulkImports::Groups::Pipelines::LabelsPipeline
+          BulkImports::Groups::Pipelines::LabelsPipeline,
+          BulkImports::Groups::Pipelines::MilestonesPipeline
         ]
       end
     end

spec/lib/bulk_imports/groups/graphql/get_milestones_query_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe BulkImports::Groups::Graphql::GetMilestonesQuery do
+  it 'has a valid query' do
+    entity = create(:bulk_import_entity)
+    context = BulkImports::Pipeline::Context.new(entity)
+
+    query = GraphQL::Query.new(
+      GitlabSchema,
+      described_class.to_s,
+      variables: described_class.variables(context)
+    )
+    result = GitlabSchema.static_validator.validate(query)
+
+    expect(result[:errors]).to be_empty
+  end
+
+  describe '#data_path' do
+    it 'returns data path' do
+      expected = %w[data group milestones nodes]
+
+      expect(described_class.data_path).to eq(expected)
+    end
+  end
+
+  describe '#page_info_path' do
+    it 'returns pagination information path' do
+      expected = %w[data group milestones page_info]
+
+      expect(described_class.page_info_path).to eq(expected)
+    end
+  end
+end

spec/lib/bulk_imports/groups/pipelines/milestones_pipeline_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe BulkImports::Groups::Pipelines::MilestonesPipeline do
+  let_it_be(:user) { create(:user) }
+  let_it_be(:group) { create(:group) }
+  let_it_be(:cursor) { 'cursor' }
+  let_it_be(:timestamp) { Time.new(2020, 01, 01).utc }
+  let_it_be(:bulk_import) { create(:bulk_import, user: user) }
+
+  let(:entity) do
+    create(
+      :bulk_import_entity,
+      bulk_import: bulk_import,
+      source_full_path: 'source/full/path',
+      destination_name: 'My Destination Group',
+      destination_namespace: group.full_path,
+      group: group
+    )
+  end
+
+  let(:context) { BulkImports::Pipeline::Context.new(entity) }
+
+  subject { described_class.new(context) }
+
+  def milestone_data(title)
+    {
+      'title' => title,
+      'description' => 'desc',
+      'state' => 'closed',
+      'start_date' => '2020-10-21',
+      'due_date' => '2020-10-22',
+      'created_at' => timestamp.to_s,
+      'updated_at' => timestamp.to_s
+    }
+  end
+
+  def extracted_data(title:, has_next_page:, cursor: nil)
+    page_info = {
+      'end_cursor' => cursor,
+      'has_next_page' => has_next_page
+    }
+
+    BulkImports::Pipeline::ExtractedData.new(data: [milestone_data(title)], page_info: page_info)
+  end
+
+  before do
+    group.add_owner(user)
+  end
+
+  describe '#run' do
+    it 'imports group milestones' do
+      first_page = extracted_data(title: 'milestone1', has_next_page: true, cursor: cursor)
+      last_page = extracted_data(title: 'milestone2', has_next_page: false)
+
+      allow_next_instance_of(BulkImports::Common::Extractors::GraphqlExtractor) do |extractor|
+        allow(extractor)
+          .to receive(:extract)
+          .and_return(first_page, last_page)
+      end
+
+      expect { subject.run }.to change(Milestone, :count).by(2)
+
+      expect(group.milestones.pluck(:title)).to contain_exactly('milestone1', 'milestone2')
+
+      milestone = group.milestones.last
+
+      expect(milestone.description).to eq('desc')
+      expect(milestone.state).to eq('closed')
+      expect(milestone.start_date.to_s).to eq('2020-10-21')
+      expect(milestone.due_date.to_s).to eq('2020-10-22')
+      expect(milestone.created_at).to eq(timestamp)
+      expect(milestone.updated_at).to eq(timestamp)
+    end
+  end
+
+  describe '#after_run' do
+    context 'when extracted data has next page' do
+      it 'updates tracker information and runs pipeline again' do
+        data = extracted_data(title: 'milestone', has_next_page: true, cursor: cursor)
+
+        expect(subject).to receive(:run)
+
+        subject.after_run(data)
+
+        tracker = entity.trackers.find_by(relation: :milestones)
+
+        expect(tracker.has_next_page).to eq(true)
+        expect(tracker.next_page).to eq(cursor)
+      end
+    end
+
+    context 'when extracted data has no next page' do
+      it 'updates tracker information and does not run pipeline' do
+        data = extracted_data(title: 'milestone', has_next_page: false)
+
+        expect(subject).not_to receive(:run)
+
+        subject.after_run(data)
+
+        tracker = entity.trackers.find_by(relation: :milestones)
+
+        expect(tracker.has_next_page).to eq(false)
+        expect(tracker.next_page).to be_nil
+      end
+    end
+  end
+
+  describe '#load' do
+    it 'creates the milestone' do
+      data = milestone_data('milestone')
+
+      expect { subject.load(context, data) }.to change(Milestone, :count).by(1)
+    end
+
+    context 'when user is not authorized to create the milestone' do
+      before do
+        allow(user).to receive(:can?).with(:admin_milestone, group).and_return(false)
+      end
+
+      it 'raises NotAllowedError' do
+        data = extracted_data(title: 'milestone', has_next_page: false)
+
+        expect { subject.load(context, data) }.to raise_error(::BulkImports::Pipeline::NotAllowedError)
+      end
+    end
+  end
+
+  describe 'pipeline parts' do
+    it { expect(described_class).to include_module(BulkImports::Pipeline) }
+    it { expect(described_class).to include_module(BulkImports::Pipeline::Runner) }
+
+    it 'has extractors' do
+      expect(described_class.get_extractor)
+        .to eq(
+          klass: BulkImports::Common::Extractors::GraphqlExtractor,
+          options: {
+            query: BulkImports::Groups::Graphql::GetMilestonesQuery
+          }
+        )
+    end
+
+    it 'has transformers' do
+      expect(described_class.transformers)
+        .to contain_exactly(
+          { klass: BulkImports::Common::Transformers::ProhibitedAttributesTransformer, options: nil }
+        )
+    end
+  end
+end

spec/lib/bulk_imports/importers/group_importer_spec.rb

@@ -22,6 +22,7 @@ RSpec.describe BulkImports::Importers::GroupImporter do
       expect_to_run_pipeline BulkImports::Groups::Pipelines::SubgroupEntitiesPipeline, context: context
       expect_to_run_pipeline BulkImports::Groups::Pipelines::MembersPipeline, context: context
       expect_to_run_pipeline BulkImports::Groups::Pipelines::LabelsPipeline, context: context
+      expect_to_run_pipeline BulkImports::Groups::Pipelines::MilestonesPipeline, context: context
 
       if Gitlab.ee?
         expect_to_run_pipeline('EE::BulkImports::Groups::Pipelines::EpicsPipeline'.constantize, context: context)