Prompt template integration (#101)

* core functionality

* prompt spec

* renamed Prompt to Prompting

took it out of the model folder due to naming collision with the actual AR model

* copy change

* rubocop & standardrb fixes

* Update README.md

* fixes

* Fix spec

* Code comments

---------

Co-authored-by: Andrei Bondarev <[email protected]>
Co-authored-by: Andrei Bondarev <[email protected]>

Author: sergiobayona

Gemfile

@@ -9,10 +9,11 @@ gem "rake", "~> 13.2"
 
 gem "rspec", "~> 3.13"
 
-gem "bundler-audit", require: false
 gem "brakeman", require: false
+gem "bundler-audit", require: false
 gem "rubocop", require: false
 
 gem "standardrb"
 
+gem "generator_spec"
 gem "langchainrb"

Gemfile.lock

@@ -103,6 +103,9 @@ GEM
     diff-lcs (1.5.1)
     drb (2.2.1)
     erubi (1.12.0)
+    generator_spec (0.10.0)
+      activesupport (>= 3.0.0)
+      railties (>= 3.0.0)
     globalid (1.2.1)
       activesupport (>= 6.1)
     i18n (1.14.5)
@@ -294,6 +297,7 @@ PLATFORMS
 DEPENDENCIES
   brakeman
   bundler-audit
+  generator_spec
   langchainrb
   langchainrb_rails!
   pry-byebug (~> 3.10.0)

README.md

@@ -129,3 +129,20 @@ Pinecone Generator does the following:
 2. Adds necessary code to the ActiveRecord model to enable vectorsearch
 3. Adds `pinecone` gem to the Gemfile
 
+### Prompt Generator - adds prompt templating capabilities to your ActiveRecord model
+```bash
+rails generate langchainrb_rails:prompt
+```
+
+This generator adds the following files to your Rails project:
+1. An ActiveRecord `Prompt` model at `app/models/prompt.rb`
+2. A rails migration to create the `prompts` table
+
+You can then use the `Prompt` model to create and manage prompts for your model.
+
+Example usage:
+```ruby
+prompt = Prompt.create!(template: "Tell me a {adjective} joke about {subject}.")
+prompt.render(adjective: "funny", subject: "elephants")
+# => "Tell me a funny joke about elephants."
+```

lib/langchainrb_rails.rb

@@ -6,6 +6,7 @@
 require_relative "langchainrb_rails/version"
 require "langchainrb_rails/railtie"
 require "langchainrb_rails/config"
+require "langchainrb_rails/prompting"
 require_relative "langchainrb_overrides/vectorsearch/pgvector"
 
 module LangchainrbRails
@@ -20,6 +21,7 @@ module Generators
     autoload :ChromaGenerator, "langchainrb_rails/generators/langchainrb_rails/chroma_generator"
     autoload :PgvectorGenerator, "langchainrb_rails/generators/langchainrb_rails/pgvector_generator"
     autoload :QdrantGenerator, "langchainrb_rails/generators/langchainrb_rails/qdrant_generator"
+    autoload :PromptGenerator, "langchainrb_rails/generators/langchainrb_rails/prompt_generator"
   end
 
   class << self

lib/langchainrb_rails/generators/langchainrb_rails/base_generator.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require "rails/generators"
 require "rails/generators/active_record"
 
@@ -18,7 +20,7 @@ class BaseGenerator < Rails::Generators::Base
         "ollama" => "Langchain::LLM::Ollama",
         "openai" => "Langchain::LLM::OpenAI",
         "replicate" => "Langchain::LLM::Replicate"
-      }
+      }.freeze
 
       def post_install_message
         say "Please do the following to start Q&A with your #{model_name} records:", :green

lib/langchainrb_rails/generators/langchainrb_rails/prompt_generator.rb

@@ -0,0 +1,28 @@
+# frozen_string_literal: true
+
+require "rails/generators"
+require "rails/generators/active_record"
+
+module LangchainrbRails
+  module Generators
+    # Adds prompt templating capabilities to your ActiveRecord model
+    #
+    # Usage:
+    #     rails generate langchainrb_rails:prompt
+    #
+    class PromptGenerator < Rails::Generators::Base
+      include ::ActiveRecord::Generators::Migration
+
+      source_root File.join(__dir__, "templates")
+
+      def create_prompt_model
+        template "prompt_model.rb", "app/models/prompt.rb"
+        migration_template "create_prompts.rb", "db/migrate/create_prompts.rb"
+      end
+
+      def migration_version
+        "[#{::ActiveRecord::VERSION::MAJOR}.#{::ActiveRecord::VERSION::MINOR}]"
+      end
+    end
+  end
+end

lib/langchainrb_rails/generators/langchainrb_rails/templates/create_prompts.rb.tt

@@ -0,0 +1,9 @@
+class CreatePrompts < ActiveRecord::Migration<%= migration_version %>
+  def change
+    create_table :prompts do |t|
+      t.text :template, null: false
+
+      t.timestamps
+    end
+  end
+end

lib/langchainrb_rails/generators/langchainrb_rails/templates/prompt_model.rb.tt

@@ -0,0 +1,3 @@
+class Prompt < ApplicationRecord
+  include LangchainrbRails::Prompting
+end

lib/langchainrb_rails/prompting.rb

@@ -0,0 +1,22 @@
+# frozen_string_literal: true
+
+module LangchainrbRails
+  module Prompting
+    extend ActiveSupport::Concern
+
+    included do
+      validates :template, presence: true
+
+      def render(variables = {})
+        template.gsub(/\{(\w+)\}/) do |match|
+          variable = ::Regexp.last_match(1).to_sym
+          variables.fetch(variable, match)
+        end
+      end
+
+      def template_variables
+        template.scan(/\{(\w+)\}/).flatten.uniq
+      end
+    end
+  end
+end

lib/langchainrb_rails/railtie.rb

@@ -13,6 +13,7 @@ class Railtie < Rails::Railtie
       require_relative "generators/langchainrb_rails/pinecone_generator"
       require_relative "generators/langchainrb_rails/pgvector_generator"
       require_relative "generators/langchainrb_rails/qdrant_generator"
+      require_relative "generators/langchainrb_rails/prompt_generator"
     end
   end
 end