use a single index in elasticsearch for both document types.

WARNING: Must rebuild search index!

Starting with this change, the name of the search index used by the
service has changed.  The new search index must be created before
deploying this version of the application.  There are two ways of doing
this:

* Offline (recommended)
Follow [these instructions](https://github.com/edx/cs_comments_service/wiki/Search-Indexes#offline-procedure) to perform an offline rebuild.

* Online
1. Deploy this code to a host which is not serving HTTP requests, and
run `rake search:rebuild`
2. When the rebuild finishes, deploy the updated code on live servers.
3. run `rake search:catchup[MINUTES]` where minutes is the amount of
time it took to run rebuild in step 1.
4. run `rake search:prune`

app.rb

@@ -53,6 +53,7 @@ CommentService.config = YAML.load(application_yaml).with_indifferent_access
 
 Tire.configure do
   url CommentService.config[:elasticsearch_server]
+  logger STDERR if ENV["ENABLE_ELASTICSEARCH_DEBUGGING"]
 end
 
 Mongoid.load!("config/mongoid.yml", environment)
@@ -75,6 +76,10 @@ Dir[File.dirname(__FILE__) + '/lib/**/*.rb'].each {|file| require file}
 Dir[File.dirname(__FILE__) + '/models/*.rb'].each {|file| require file}
 Dir[File.dirname(__FILE__) + '/presenters/*.rb'].each {|file| require file}
 
+# Ensure elasticsearch index mappings exist.
+Comment.put_search_index_mapping
+CommentThread.put_search_index_mapping
+
 # Comment out observers until notifications are actually set up properly.
 #Dir[File.dirname(__FILE__) + '/models/observers/*.rb'].each {|file| require file}
 #Mongoid.observers = PostReplyObserver, PostTopicObserver, AtUserObserver

models/comment.rb

@@ -30,9 +30,14 @@ class Comment < Content
   include Tire::Model::Search
   include Tire::Model::Callbacks
 
+  index_name Content::ES_INDEX_NAME
+
   mapping do
     indexes :body, type: :string, analyzer: :english, stored: true, term_vector: :with_positions_offsets
     indexes :course_id, type: :string, index: :not_analyzed, included_in_all: false
+    indexes :comment_thread_id, type: :string, index: :not_analyzed, included_in_all: false, as: 'comment_thread_id'
+    indexes :commentable_id, type: :string, index: :not_analyzed, included_in_all: false, as: 'commentable_id'
+    indexes :group_id, type: :string, index: :not_analyzed, included_in_all: false, as: 'group_id'
     indexes :created_at, type: :date, included_in_all: false
     indexes :updated_at, type: :date, included_in_all: false
   end
@@ -111,6 +116,19 @@ class Comment < Content
         t.commentable_id
       end
     end
+  rescue Mongoid::Errors::DocumentNotFound
+    nil
+  end
+
+  def group_id
+    if self.comment_thread_id
+      t = CommentThread.find self.comment_thread_id
+      if t
+        t.group_id
+      end
+    end
+  rescue Mongoid::Errors::DocumentNotFound
+    nil
   end
 
   def self.by_date_range_and_thread_ids from_when, to_when, thread_ids

models/comment_thread.rb

@@ -26,6 +26,8 @@ class CommentThread < Content
   include Tire::Model::Search
   include Tire::Model::Callbacks
 
+  index_name Content::ES_INDEX_NAME
+
   mapping do
     indexes :title, type: :string, analyzer: :english, boost: 5.0, stored: true, term_vector: :with_positions_offsets
     indexes :body, type: :string, analyzer: :english, stored: true, term_vector: :with_positions_offsets
@@ -97,10 +99,11 @@ class CommentThread < Content
       
     #so first, find the comment threads associated with comments that hit the query
         
-    search = Tire::Search::Search.new 'comment_threads'
+    search = Tire::Search::Search.new Content::ES_INDEX_NAME
 
     search.query {|query| query.match [:title, :body], params["text"]} if params["text"]
     search.highlight({title: { number_of_fragments: 0 } } , {body: { number_of_fragments: 0 } }, options: { tag: "<highlight>" })
+    search.filter(:type, value: 'comment_thread')
     search.filter(:term, commentable_id: params["commentable_id"]) if params["commentable_id"]
     search.filter(:terms, commentable_id: params["commentable_ids"]) if params["commentable_ids"]
     search.filter(:term, course_id: params["course_id"]) if params["course_id"]
@@ -117,8 +120,9 @@ class CommentThread < Content
     #again, b/c there is no relationship in ordinality, we cannot paginate if it's a text query
     results = search.results
 
-    search = Tire::Search::Search.new 'comments'
+    search = Tire::Search::Search.new Content::ES_INDEX_NAME
     search.query {|query| query.match :body, params["text"]} if params["text"]
+    search.filter(:type, value: 'comment')
     search.filter(:term, course_id: params["course_id"]) if params["course_id"]
     search.size CommentService.config["max_deep_search_comment_count"].to_i
 
@@ -151,7 +155,8 @@ class CommentThread < Content
     end
     
     #now run one more search to harvest the threads and filter by group
-    search = Tire::Search::Search.new 'comment_threads'
+    search = Tire::Search::Search.new Content::ES_INDEX_NAME
+    search.filter(:type, value: 'comment_thread')
     search.filter(:terms, :thread_id => thread_ids)
     search.filter(:terms, commentable_id: params["commentable_ids"]) if params["commentable_ids"]
     search.filter(:term, course_id: params["course_id"]) if params["course_id"]

models/content.rb

@@ -16,6 +16,16 @@ class Content
   index({comment_thread_id: 1, endorsed: 1}, {sparse: true})
   index({commentable_id: 1}, {sparse: true, background: true})
 
+  ES_INDEX_NAME = 'content'
+
+  def self.put_search_index_mapping(idx=nil)
+    idx ||= self.tire.index
+    success = idx.mapping(self.tire.document_type, {:properties => self.tire.mapping})
+    unless success
+      logger.warn "WARNING! could not apply search index mapping for #{self.name}"
+    end
+  end
+
   before_save :set_username
   def set_username
     # avoid having to look this attribute up later, since it does not change
@@ -29,7 +39,7 @@ class Content
       (anonymous || anonymous_to_peers) ? attr_when_anonymous : author.send(attr)
     end
   end
-  
+
   def self.flagged
     #return an array of flagged content
     holder = []

spec/api/search_spec.rb

@@ -9,8 +9,8 @@ describe "app" do
     let(:author) { create_test_user(42) }
 
     describe "GET /api/v1/search/threads" do
-      it "returns the correct values for total_results and num_pages", :focus => true do
-        course_id = "test_course_id"
+      it "returns the correct values for total_results and num_pages" do
+        course_id = "test/course/id"
         for i in 1..100 do
           text = "all"
           text += " half" if i % 2 == 0
@@ -24,8 +24,7 @@ describe "app" do
         end
         # Elasticsearch does not necessarily make newly indexed content
         # available immediately, so we must explicitly refresh the index
-        CommentThread.tire.index.refresh
-        Comment.tire.index.refresh
+        refresh_es_index
 
         test_text = lambda do |text, expected_total_results, expected_num_pages|
           get "/api/v1/search/threads", course_id: course_id, text: text, per_page: "10"
@@ -46,12 +45,12 @@ describe "app" do
         # Elasticsearch may not be able to handle searching for non-ASCII text,
         # so prepend the text with an ASCII term we can search for.
         search_term = "artichoke"
-        course_id = "unicode_course"
+        course_id = "unicode/course"
         thread = make_thread(author, "#{search_term} #{text}", course_id, "unicode_commentable")
         make_comment(author, thread, text)
         # Elasticsearch does not necessarily make newly indexed content
         # available immediately, so we must explicitly refresh the index
-        CommentThread.tire.index.refresh
+        refresh_es_index
         get "/api/v1/search/threads", course_id: course_id, text: search_term
         last_response.should be_ok
         result = parse(last_response.body)["collection"]

spec/spec_helper.rb

@@ -28,6 +28,25 @@ def set_api_key_header
   current_session.header "X-Edx-Api-Key", TEST_API_KEY
 end
 
+def delete_es_index
+  Tire.index Content::ES_INDEX_NAME do delete end
+end
+
+def create_es_index
+  new_index = Tire.index Content::ES_INDEX_NAME
+  new_index.create
+  [CommentThread, Comment].each do |klass|
+    klass.put_search_index_mapping
+  end
+end
+
+def refresh_es_index
+  # we are using the same index for two types, which is against the
+  # grain of Tire's design.  This is why this method works for both
+  # comment_threads and comments.
+  CommentThread.tire.index.refresh
+end
+
 RSpec.configure do |config|
   config.include Rack::Test::Methods
   config.treat_symbols_as_metadata_keys_with_true_values = true
@@ -36,10 +55,8 @@ RSpec.configure do |config|
   config.before(:each) do
     Mongoid::IdentityMap.clear
     DatabaseCleaner.clean
-    [CommentThread, Comment].each do |class_|
-      class_.tire.index.delete
-      class_.create_elasticsearch_index
-    end
+    delete_es_index
+    create_es_index
   end
 end
 
@@ -59,8 +76,8 @@ def init_without_subscriptions
 
   [Comment, CommentThread, User, Notification, Subscription, Activity, Delayed::Backend::Mongoid::Job].each(&:delete_all).each(&:remove_indexes).each(&:create_indexes)
   Content.mongo_session[:blocked_hash].drop
-  Tire.index 'comment_threads' do delete end
-  CommentThread.create_elasticsearch_index
+  delete_es_index
+  create_es_index
   
   commentable = Commentable.new("question_1")
 
@@ -140,8 +157,8 @@ end
 def init_with_subscriptions
   [Comment, CommentThread, User, Notification, Subscription, Activity, Delayed::Backend::Mongoid::Job].each(&:delete_all).each(&:remove_indexes).each(&:create_indexes)
 
-  Tire.index 'comment_threads' do delete end
-  CommentThread.create_elasticsearch_index
+  delete_es_index
+  create_es_index
 
   user1 = create_test_user(1)
   user2 = create_test_user(2)