[Fix #594] Reindex implementation (#784)

.rubocop.yml

@@ -57,4 +57,5 @@ Metrics/BlockLength:
 
 Metrics/ModuleLength:
   Exclude:
+    - 'lib/chewy/rake_helper.rb'
     - '**/*_spec.rb'

CHANGELOG.md

@@ -10,6 +10,9 @@
 
 ### Changes
 
+  * [#594](https://github.com/toptal/chewy/issues/594): Add `.reindex` to Index class ([@Vitalina-Vakulchyk][]):
+    * Wrapped Elasticsearch gem `.reindex` with `.reindex` in Index class
+    * Add `rake chewy:reindex` task
   * [#679](https://github.com/toptal/chewy/issues/679): Wrapped `Elasticsearch::API::Indices::Actions#clear_cache` with `.clear_cache` in Index class ([@Vitalina-Vakulchyk][])
   * [#495](https://github.com/toptal/chewy/issues/495): Ability to change Rails console strategy with `Chewy.console_strategy` ([@Vitalina-Vakulchyk][])
   * [#778](https://github.com/toptal/chewy/pull/778): **(Breaking)** Drop support for Ruby 2.5 ([@Vitalina-Vakulchyk][])

lib/chewy/index/actions.rb

@@ -225,6 +225,18 @@ def clear_cache(args = {index: index_name})
           client.indices.clear_cache(args)
         end
 
+        def reindex(source: index_name, dest: index_name)
+          client.reindex(
+            {
+              body:
+                {
+                  source: {index: source},
+                  dest: {index: dest}
+                }
+            }
+          )
+        end
+
       private
 
         def optimize_index_settings(index_name)

lib/chewy/rake_helper.rb

@@ -203,6 +203,20 @@ def all_indexes
         Chewy::Index.descendants - [Chewy::Stash::Journal, Chewy::Stash::Specification]
       end
 
+      # Reindex data from source index to destination index
+      #
+      # @example
+      #   Chewy::RakeHelper.reindex(source: 'users_index', dest: 'cities_index') reindex data from 'users_index' index to 'cities_index'
+      #
+      # @param source [String], dest [String] indexes to reindex
+      def reindex(source:, dest:, output: $stdout)
+        subscribed_task_stats(output) do
+          output.puts "Source index is #{source}\nDestination index is #{dest}"
+          Chewy::Index.reindex(source: source, dest: dest)
+          output.puts "#{source} index successfully reindexed with #{dest} index data"
+        end
+      end
+
       def normalize_indexes(*identifiers)
         identifiers.flatten(1).map { |identifier| normalize_index(identifier) }
       end

lib/tasks/chewy.rake

@@ -47,6 +47,11 @@ namespace :chewy do
     Chewy::RakeHelper.sync(except: processed)
   end
 
+  desc 'Reindex data from source index to destination index'
+  task :reindex, %i[source dest] => :environment do |_task, args|
+    Chewy::RakeHelper.reindex(source: args[:source], dest: args[:dest])
+  end
+
   namespace :parallel do
     desc 'Parallel version of `rake chewy:reset`'
     task reset: :environment do |_task, args|

spec/chewy/index/actions_spec.rb

@@ -731,4 +731,75 @@
       end
     end
   end
+
+  describe '.reindex' do
+    before do
+      stub_model(:city)
+      stub_index(:cities) do
+        define_type City
+      end
+      CitiesIndex.create(source_index)
+      DummiesIndex.create(dest_index)
+    end
+
+    let(:source_index) { 'source_index' }
+    let(:source_index_with_prefix) { 'cities_source_index' }
+    let(:dest_index) { 'dest_index' }
+    let(:dest_index_with_prefix) { 'dummies_dest_index' }
+    let(:unexisting_index) { 'wrong_index' }
+
+    context 'with existing indexes' do
+      specify do
+        expect(CitiesIndex)
+          .to receive(:reindex)
+          .and_call_original
+        expect { CitiesIndex.reindex(source: source_index_with_prefix, dest: dest_index_with_prefix) }
+          .not_to raise_error
+      end
+    end
+
+    context 'with unexisting indexes' do
+      context 'source index' do
+        specify do
+          expect(CitiesIndex)
+            .to receive(:reindex)
+            .and_call_original
+          expect { CitiesIndex.reindex(source: unexisting_index, dest: dest_index_with_prefix) }
+            .to raise_error Elasticsearch::Transport::Transport::Errors::NotFound
+        end
+      end
+
+      context 'dest index' do
+        specify do
+          expect(CitiesIndex)
+            .to receive(:reindex)
+            .and_call_original
+          expect { CitiesIndex.reindex(source: source_index_with_prefix, dest: unexisting_index) }
+            .not_to raise_error
+        end
+      end
+    end
+
+    context 'with missing indexes' do
+      context 'without dest index' do
+        specify do
+          expect(DummiesIndex)
+            .to receive(:reindex)
+            .and_call_original
+          expect { DummiesIndex.reindex(source: source_index_with_prefix) }
+            .not_to raise_error
+        end
+      end
+
+      context 'without source index' do
+        specify do
+          expect(CitiesIndex)
+            .to receive(:reindex)
+            .and_call_original
+          expect { CitiesIndex.reindex(dest: dest_index_with_prefix) }
+            .not_to raise_error
+        end
+      end
+    end
+  end
 end

spec/chewy/rake_helper_spec.rb

@@ -393,4 +393,46 @@
       OUTPUT
     end
   end
+
+  describe '.reindex' do
+    before do
+      journal
+      CitiesIndex.create!
+      CountriesIndex.create!
+    end
+
+    let(:source_index) { 'cities' }
+    let(:dest_index) { 'countries' }
+
+    context 'with correct arguments' do
+      specify do
+        output = StringIO.new
+        described_class.reindex(source: source_index, dest: dest_index, output: output)
+        expect(output.string).to match(Regexp.new(<<-OUTPUT, Regexp::MULTILINE))
+\\Source index is cities
+\\Destination index is countries
+cities index successfully reindexed with countries index data
+Total: \\d+s\\Z
+        OUTPUT
+      end
+    end
+
+    context 'with missing indexes' do
+      context 'without dest index' do
+        specify do
+          output = StringIO.new
+          expect { described_class.reindex(source: source_index, output: output) }
+            .to raise_error ArgumentError
+        end
+      end
+
+      context 'without source index' do
+        specify do
+          output = StringIO.new
+          expect { described_class.reindex(dest: dest_index, output: output) }
+            .to raise_error ArgumentError
+        end
+      end
+    end
+  end
 end