FEATURE: Support for locally infered embeddings in 100 languages (#115)

* FEATURE: Support for locally infered embeddings in 100 languages

* add table

config/locales/server.en.yml

@@ -46,13 +46,11 @@ en:
     ai_embeddings_enabled: "Enable the embeddings module."
     ai_embeddings_discourse_service_api_endpoint: "URL where the API is running for the embeddings module"
     ai_embeddings_discourse_service_api_key: "API key for the embeddings API"
-    ai_embeddings_models: "Discourse will generate embeddings for each of the models enabled here"
-    ai_embeddings_semantic_related_model: "Model to use for related topics."
+    ai_embeddings_model: "Use all-mpnet-base-v2 for local and fast inference in english, text-embedding-ada-002 to use OpenAI API (need API key) and multilingual-e5-large for local multilingual embeddings"
     ai_embeddings_generate_for_pms: "Generate embeddings for personal messages."
     ai_embeddings_semantic_related_topics_enabled: "Use Semantic Search for related topics."
     ai_embeddings_semantic_related_topics: "Maximum number of topics to show in related topic section."
     ai_embeddings_pg_connection_string: "PostgreSQL connection string for the embeddings module. Needs pgvector extension enabled and a series of tables created. See docs for more info."
-    ai_embeddings_semantic_search_model: "Model to use for semantic search."
     ai_embeddings_semantic_search_enabled: "Enable full-page semantic search."
     ai_embeddings_semantic_related_include_closed_topics: "Include closed topics in semantic search results"
 

config/settings.yml

@@ -154,6 +154,7 @@ plugins:
     choices:
      - all-mpnet-base-v2
      - text-embedding-ada-002
+     - multilingual-e5-large
   ai_embeddings_generate_for_pms: false
   ai_embeddings_semantic_related_topics_enabled: false
   ai_embeddings_semantic_related_topics: 5

db/migrate/20230710171141_enable_pg_vector_extension.rb

@@ -2,6 +2,17 @@
 
 class EnablePgVectorExtension < ActiveRecord::Migration[7.0]
   def change
-    enable_extension :vector
+    begin
+      enable_extension :vector
+    rescue Exception => e
+      if DB.query_single("SELECT 1 FROM pg_available_extensions WHERE name = 'vector';").empty?
+        STDERR.puts "------------------------------DISCOURSE AI ERROR----------------------------------"
+        STDERR.puts "    Discourse AI requires the pgvector extension on the PostgreSQL database."
+        STDERR.puts "         Run a `./launcher rebuild app` to fix it on a standard install."
+        STDERR.puts "            Alternatively, you can remove Discourse AI to rebuild."
+        STDERR.puts "------------------------------DISCOURSE AI ERROR----------------------------------"
+      end
+      raise e
+    end
   end
 end

db/migrate/20230727170222_create_multilingual_topic_embeddings_table.rb

@@ -0,0 +1,25 @@
+# frozen_string_literal: true
+
+class CreateMultilingualTopicEmbeddingsTable < ActiveRecord::Migration[7.0]
+  def change
+    models = [DiscourseAi::Embeddings::Models::MultilingualE5Large]
+    strategies = [DiscourseAi::Embeddings::Strategies::Truncation]
+
+    models.each do |model|
+      strategies.each do |strategy|
+        table_name = "ai_topic_embeddings_#{model.id}_#{strategy.id}".to_sym
+
+        create_table table_name, id: false do |t|
+          t.integer :topic_id, null: false
+          t.integer :model_version, null: false
+          t.integer :strategy_version, null: false
+          t.text :digest, null: false
+          t.column :embeddings, "vector(#{model.dimensions})", null: false
+          t.timestamps
+
+          t.index :topic_id, unique: true
+        end
+      end
+    end
+  end
+end

lib/modules/embeddings/entry_point.rb

@@ -7,6 +7,7 @@ module DiscourseAi
         require_relative "models/base"
         require_relative "models/all_mpnet_base_v2"
         require_relative "models/text_embedding_ada_002"
+        require_relative "models/multilingual_e5_large"
         require_relative "strategies/truncation"
         require_relative "manager"
         require_relative "jobs/regular/generate_embeddings"

lib/modules/embeddings/models/multilingual_e5_large.rb

@@ -0,0 +1,52 @@
+# frozen_string_literal: true
+
+module DiscourseAi
+  module Embeddings
+    module Models
+      class MultilingualE5Large < Base
+        class << self
+          def id
+            3
+          end
+
+          def version
+            1
+          end
+
+          def name
+            "multilingual-e5-large"
+          end
+
+          def dimensions
+            1024
+          end
+
+          def max_sequence_length
+            512
+          end
+
+          def pg_function
+            "<=>"
+          end
+
+          def pg_index_type
+            "vector_cosine_ops"
+          end
+
+          def generate_embeddings(text)
+            DiscourseAi::Inference::DiscourseClassifier.perform!(
+              "#{SiteSetting.ai_embeddings_discourse_service_api_endpoint}/api/v1/classify",
+              name,
+              "query: #{text}",
+              SiteSetting.ai_embeddings_discourse_service_api_key,
+            )
+          end
+
+          def tokenizer
+            DiscourseAi::Tokenizer::MultilingualE5LargeTokenizer
+          end
+        end
+      end
+    end
+  end
+end

lib/shared/tokenizer/tokenizer.rb

@@ -59,6 +59,13 @@ module DiscourseAi
       end
     end
 
+    class MultilingualE5LargeTokenizer < BasicTokenizer
+      def self.tokenizer
+        @@tokenizer ||=
+          Tokenizers.from_file("./plugins/discourse-ai/tokenizers/multilingual-e5-large.json")
+      end
+    end
+
     class OpenAiTokenizer < BasicTokenizer
       class << self
         def tokenizer

plugin.rb

@@ -68,13 +68,4 @@ after_initialize do
   on(:reviewable_transitioned_to) do |new_status, reviewable|
     ModelAccuracy.adjust_model_accuracy(new_status, reviewable)
   end
-
-  if DB.query_single("SELECT 1 FROM pg_available_extensions WHERE name = 'vector';").empty?
-    STDERR.puts "------------------------------DISCOURSE AI ERROR----------------------------------"
-    STDERR.puts "    Discourse AI requires the pgvector extension on the PostgreSQL database."
-    STDERR.puts "         Run a `./launcher rebuild app` to fix it on a standard install."
-    STDERR.puts "            Alternatively, you can remove Discourse AI to rebuild."
-    STDERR.puts "------------------------------DISCOURSE AI ERROR----------------------------------"
-    exit 1
-  end
 end

spec/shared/tokenizer_spec.rb

@@ -117,3 +117,20 @@ describe DiscourseAi::Tokenizer::Llama2Tokenizer do
     end
   end
 end
+
+describe DiscourseAi::Tokenizer::MultilingualE5LargeTokenizer do
+  describe "#size" do
+    describe "returns a token count" do
+      it "for a sentence with punctuation and capitalization and numbers" do
+        expect(described_class.size("Hello, World! 123")).to eq(7)
+      end
+    end
+  end
+
+  describe "#truncate" do
+    it "truncates a sentence" do
+      sentence = "foo bar baz qux quux corge grault garply waldo fred plugh xyzzy thud"
+      expect(described_class.truncate(sentence, 3)).to eq("foo")
+    end
+  end
+end

tokenizers/README.md

@@ -13,3 +13,7 @@ Licensed under Apache License
 ## llama-2-70b-chat-hf
 
 Licensed under LLAMA 2 COMMUNITY LICENSE AGREEMENT
+
+## multilingual-e5-large
+
+Licensed under MIT License