Merge pull request #17 from Sage/feature_index_alias

Feature - Index Alias

Author: adamgeorgeson

Gemfile

@@ -1,5 +1,7 @@
 source 'https://rubygems.org'
 
+gem 'json', '2.1.0'
+
 # Specify your gem's dependencies in elastic_search_framework.gemspec
 gemspec
 

README.md

@@ -51,6 +51,60 @@ This is used to set the port that should be used for all connection actions.
 
 > DEFAULT = 9200
 
+# IndexAlias
+To define an index alias within elasticsearch, create an index alias class that extends from the `ElasticSearchFramework::IndexAlias` module.
+
+Example:
+
+
+```ruby
+class ExampleIndexAlias
+  extend ElasticSearchFramework::IndexAlias
+
+  index ExampleIndex, active: true
+  index ExampleIndex2, active: false
+
+  name :example
+end
+```
+
+**attributes**
+
+ - **index** [Hash] [Required] [Multi] This is used to specify the indexes associated with this alias and which index is the current active index for the alias to point to.
+ - **name** [Hash] [Required] [Single] This is used to specify the unique name of the index alias.
+
+---
+
+Index Aliases are required to decouple your application from a specific index and allow you to handle index updates without downtime.
+
+To change the mapping of an existing index Create a new version of the index, then associate the new index with the index alias as an inactive index `active: false`. This will allow index writes and deletes to be performed on both indexes so no new data is lost while you perform a `_reindex` operation to move existing data from the old index into the new index.
+
+Once you have `_reindexed` into your new index you can then de-activate the old index `active: false` and activate the new index `active: true` in your index alias. This will swap all requests to the new index.
+
+Doing the above steps should enable you to seamlessly transition between 1 index and another when mapping/analyzer changes are required.
+
+## #create
+This method is called to create the index alias within an elastic search instance.
+> This method is idempotent and will modify the index alias if it already exists.
+
+> All associated indexes must exist before this method is called.
+
+    ExampleIndexAlias.create
+
+## Index operation methods
+The following index operation methods are available for an index alias:
+
+- `#get_item`
+- `#put_item`
+- `#delete_item`
+- `#query`
+
+> `#put_item` calls will be performed against all indexes associated with the alias.
+
+> `#delete_item` calls will be performed against all indexes associated with the alias.
+
+> Details for how to use the above index operation methods can be found below.
+
 # Index
 To define an index within elasticsearch, create an index definition class that extends from the `ElasticSearchFramework::Index` module.
 

lib/elastic_search_framework.rb

@@ -8,6 +8,7 @@
 require_relative 'elastic_search_framework/exceptions'
 require_relative 'elastic_search_framework/repository'
 require_relative 'elastic_search_framework/index'
+require_relative 'elastic_search_framework/index_alias'
 require_relative 'elastic_search_framework/query'
 
 module ElasticSearchFramework

lib/elastic_search_framework/index.rb

@@ -2,14 +2,19 @@ module ElasticSearchFramework
   module Index
     attr_accessor :index_settings
 
-    def index(name:)
+    def index(name:, version: nil)
       unless instance_variable_defined?(:@elastic_search_index_def)
-        instance_variable_set(:@elastic_search_index_def, name: "#{name}")
+        instance_variable_set(:@elastic_search_index_def, name: "#{name}#{version}")
+        instance_variable_set(:@elastic_search_index_version, version: version) unless version.nil?
       else
         raise ElasticSearchFramework::Exceptions::IndexError.new("[#{self.class}] - Duplicate index description. Name: #{name}.")
       end
     end
 
+    def version
+      instance_variable_defined?(:@elastic_search_index_version) ? instance_variable_get(:@elastic_search_index_version) : 0
+    end
+
     def id(field)
       unless instance_variable_defined?(:@elastic_search_index_id)
         instance_variable_set(:@elastic_search_index_id, field)
@@ -160,7 +165,7 @@ def host
     end
 
     def repository
-      ElasticSearchFramework::Repository.new
+      @repository ||= ElasticSearchFramework::Repository.new
     end
 
     def get_item(id:, type: 'default')

lib/elastic_search_framework/index_alias.rb

@@ -0,0 +1,146 @@
+module ElasticSearchFramework
+  module IndexAlias
+    def index(klass, active:)
+      unless instance_variable_defined?(:@elastic_search_indexes)
+        instance_variable_set(:@elastic_search_indexes, [])
+      end
+      indexes = self.instance_variable_get(:@elastic_search_indexes)
+      indexes << {klass: klass, active: active}
+      instance_variable_set(:@elastic_search_indexes, indexes)
+    end
+
+    def indexes
+      self.instance_variable_get(:@elastic_search_indexes)
+    end
+
+    def name(name)
+      unless instance_variable_defined?(:@elastic_search_index_alias_name)
+        instance_variable_set(:@elastic_search_index_alias_name, "#{name}")
+      else
+        raise ElasticSearchFramework::Exceptions::IndexError.new("[#{self.class}] - Duplicate index alias name: #{name}.")
+      end
+    end
+
+    def valid?
+      indexes.select { |i| i[:active] == true }.length == 1
+    end
+
+    def create
+      if !valid?
+        raise ElasticSearchFramework::Exceptions::IndexError.new("[#{self.class}] - Invalid Index alias.")
+      end
+
+      uri = URI("#{host}/_aliases")
+
+      payload = {
+        actions: [],
+      }
+
+      indexes.each do |index|
+        action = nil
+        if exists?(index: index[:klass])
+          action = "remove" if !index[:active]
+        else
+          action = "add" if index[:active]
+        end
+        next if action.nil?
+
+        payload[:actions] << {action => {index: index[:klass].full_name, alias: self.full_name}}
+      end
+
+      request = Net::HTTP::Post.new(uri.request_uri)
+      request.body = JSON.dump(payload)
+      request.content_type = "application/json"
+
+      response = repository.with_client do |client|
+        client.request(request)
+      end
+
+      is_valid_response?(response.code) || Integer(response.code) == 404
+    end
+
+    def delete
+      uri = URI("#{host}/_all/_aliases/#{full_name}")
+
+      request = Net::HTTP::Delete.new(uri.request_uri)
+
+      response = repository.with_client do |client|
+        client.request(request)
+      end
+
+      is_valid_response?(response.code) || Integer(response.code) == 404
+    end
+
+    def exists?(index:)
+      uri = URI("#{host}/#{index.full_name}/_alias/#{full_name}")
+
+      request = Net::HTTP::Get.new(uri.request_uri)
+
+      response = repository.with_client do |client|
+        client.request(request)
+      end
+
+      return false if response.code == "404"
+
+      result = nil
+      if is_valid_response?(response.code)
+        result = JSON.parse(response.body)
+      end
+
+      return true if !result.nil? && result[index.full_name]["aliases"] != nil
+      return false
+    end
+
+    def is_valid_response?(code)
+      [200, 201, 202].include?(Integer(code))
+    end
+
+    def full_name
+      name = instance_variable_get(:@elastic_search_index_alias_name)
+      if ElasticSearchFramework.namespace != nil
+        "#{ElasticSearchFramework.namespace}#{ElasticSearchFramework.namespace_delimiter}#{name.downcase}"
+      else
+        name.downcase
+      end
+    end
+
+    def description
+      index = indexes.last[:klass]
+      hash = index.instance_variable_get(:@elastic_search_index_def)
+      if index.instance_variable_defined?(:@elastic_search_index_id)
+        hash[:id] = index.instance_variable_get(:@elastic_search_index_id)
+      else
+        hash[:id] = :id
+      end
+      hash
+    end
+
+    def host
+      "#{ElasticSearchFramework.host}:#{ElasticSearchFramework.port}"
+    end
+
+    def repository
+      @repository ||= ElasticSearchFramework::Repository.new
+    end
+
+    def get_item(id:, type: "default")
+      repository.get(index: self, id: id, type: type)
+    end
+
+    def put_item(type: "default", item:)
+      indexes.each do |index|
+        repository.set(entity: item, index: index[:klass], type: type)
+      end
+    end
+
+    def delete_item(id:, type: "default")
+      indexes.each do |index|
+        repository.drop(index: index[:klass], id: id, type: type)
+      end
+    end
+
+    def query
+      ElasticSearchFramework::Query.new(index: self)
+    end
+  end
+end

lib/elastic_search_framework/version.rb

@@ -1,3 +1,3 @@
 module ElasticSearchFramework
-  VERSION = '2.1.0'
+  VERSION = '2.2.0'
 end

script/docker-compose.yml

@@ -2,7 +2,7 @@ version: '2.1'
 
 services:
   elasticsearch:
-    image: elasticsearch:alpine
+    image: elasticsearch:5.6-alpine
     container_name: elasticsearch
     environment:
       - "ES_JAVA_OPTS=-Xms512m -Xmx512m"