[MODEL] Added dynamic getter/setter (block/proc) for MyModel.index_name

    class Article
      index_name { "articles-#{Time.now.year}" }
    end

Closes elastic#159

Author: fbernier

elasticsearch-model/lib/elasticsearch/model/naming.rb

@@ -15,14 +15,30 @@ module ClassMethods
         #       index_name "articles-#{Rails.env}"
         #     end
         #
+        # @example Set the index name for the `Article` model and reevaluate it on each call
+        #
+        #     class Article
+        #       index_name { "articles-#{Time.now.year}" }
+        #     end
+        #
         # @example Directly set the index name for the `Article` model
         #
         #     Article.index_name "articles-#{Rails.env}"
         #
-        # TODO: Dynamic names a la Tire -- `Article.index_name { "articles-#{Time.now.year}" }`
+        # @example Directly set the index name for the `Article` model and reevaluate it on each call
         #
-        def index_name name=nil
-          @index_name = name || @index_name || self.model_name.collection.gsub(/\//, '-')
+        #     Article.index_name { "articles-#{Time.now.year}" }
+        #
+        def index_name name=nil, &block
+          if name || block_given?
+            return (@index_name = name || block)
+          end
+
+          if @index_name.respond_to?(:call)
+            @index_name.call
+          else
+            @index_name || self.model_name.collection.gsub(/\//, '-')
+          end
         end
 
         # Set the index name
@@ -67,8 +83,16 @@ module InstanceMethods
         #     @article.index_name "articles-#{@article.user_id}"
         #     @article.__elasticsearch__.update_document
         #
-        def index_name name=nil
-          @index_name = name || @index_name || self.class.index_name
+        def index_name name=nil, &block
+          if name || block_given?
+            return (@index_name = name || block)
+          end
+
+          if @index_name.respond_to?(:call)
+            @index_name.call
+          else
+            @index_name || self.class.index_name
+          end
         end
 
         # Set the index name

elasticsearch-model/test/integration/dynamic_index_name_test.rb

@@ -0,0 +1,60 @@
+require 'test_helper'
+
+module Elasticsearch
+  module Model
+    class DynamicIndexNameTest < Elasticsearch::Test::IntegrationTestCase
+
+      class ::ArticleWithDynamicIndexName < ActiveRecord::Base
+        include Elasticsearch::Model
+        include Elasticsearch::Model::Callbacks
+
+        class << self
+          attr_accessor :year
+        end
+
+        mapping { indexes :title }
+        index_name { "articles-#{year}" }
+      end
+
+      context "Dynamic index name" do
+        setup do
+          ActiveRecord::Schema.define(:version => 1) do
+            create_table :article_with_dynamic_index_names do |t|
+              t.string   :title
+            end
+          end
+        end
+
+        should 'evaluate the index_name value' do
+          ArticleWithDynamicIndexName.year = '2014'
+
+          assert_equal ArticleWithDynamicIndexName.index_name, "articles-2014"
+        end
+
+        should 'reevaluate the index_name value each time' do
+          ArticleWithDynamicIndexName.year = '2015'
+
+          assert_equal ArticleWithDynamicIndexName.index_name, "articles-2015"
+        end
+
+        should "write and read at the the defined index" do
+          ArticleWithDynamicIndexName.year = '2016'
+
+          ArticleWithDynamicIndexName.delete_all
+          ArticleWithDynamicIndexName.__elasticsearch__.create_index! force: true
+
+          ::ArticleWithDynamicIndexName.create! title: 'Test'
+
+          ArticleWithDynamicIndexName.__elasticsearch__.refresh_index!
+
+          response = ArticleWithDynamicIndexName.search(query: { match_all: {} })
+
+          assert_equal response.results.total, 1
+          assert_equal response.search.definition[:index], ArticleWithDynamicIndexName.index_name
+          assert_equal response.search.definition[:index], 'articles-2016'
+        end
+      end
+
+    end
+  end
+end

elasticsearch-model/test/unit/naming_test.rb

@@ -40,6 +40,20 @@ class DummyNamingModelInNamespace
       d = DummyNamingModel.new
       d.index_name 'foobar_d'
       assert_equal 'foobar_d', d.index_name
+
+      modifier = 'r'
+      d.index_name Proc.new{ "foobar_#{modifier}" }
+      assert_equal 'foobar_r', d.index_name
+
+      modifier = 'z'
+      assert_equal 'foobar_z', d.index_name
+
+      modifier = 'f'
+      d.index_name { "foobar_#{modifier}" }
+      assert_equal 'foobar_f', d.index_name
+
+      modifier = 't'
+      assert_equal 'foobar_t', d.index_name
     end
 
     should "set the index_name with setter" do
@@ -51,6 +65,19 @@ class DummyNamingModelInNamespace
       assert_equal 'foobar_index_s', d.index_name
 
       assert_equal 'foobar_index_S', DummyNamingModel.index_name
+
+      modifier2 = 'y'
+      DummyNamingModel.index_name = Proc.new{ "foobar_index_#{modifier2}" }
+      assert_equal 'foobar_index_y', DummyNamingModel.index_name
+
+      modifier = 'r'
+      d.index_name = Proc.new{ "foobar_index_#{modifier}" }
+      assert_equal 'foobar_index_r', d.index_name
+
+      modifier = 'z'
+      assert_equal 'foobar_index_z', d.index_name
+
+      assert_equal 'foobar_index_y', DummyNamingModel.index_name
     end
 
     should "set and return the document_type" do