Ruby on Rails integration for ChromaDB based on chroma-db gem.

chromable were tested with Ruby 3.2.2 and Rails 7.1.2.

Install chromable and add it to the application's Gemfile by executing:

$ bundle add chromable

Or, if bundler is not being used to manage dependencies, install chromable by executing:

$ gem install chromable

chromable is depending on chroma-db, so you will need to initialize it in config/initializers/chroma.rb:

require 'chroma-db'

Chroma.connect_host = ENV.fetch('CHROMA_DB_URL', 'http://localhost:8000')
Chroma.logger = Logger.new($stdout)
Chroma.log_level = Chroma::LEVEL_ERROR

Then, include Chromable module in your model and initialize it:

class Post < ApplicationRecord
  include Chromable

  chromable document: :content, metadata: %i[author category], embedder: :embed, keep_document: false

  def self.embed(text, **options)
    options[:is_query] ||= false

    if options[:is_query]
      # Call OpenAI API to embed `text` as a search query.
    else
      # Call OpenAI API to embed `text` as a post content.
    end
  end
end

Where:

• document: is a callable represents the text content you want to embed and store in ChromaDB (e.g. Could be a model attribute).
• metadata: is a list of callables to be evaluated and passed to ChromaDB as metadata to be used to filter (e.g. Could be an instance method).
• embedder: is a callable defined at the model level that returns the embedding representation for the given text based on some options.
• keep_document: tells chromable to pass the document: to ChromaDB and save it or not. It is useful if you just want to have the embeddings in ChromaDB and the rest of the data in your Rails application database to reduce memory footprint. keep_document: is true by default.

Optionaly you can pass collection_name:. If not passed, the plural form of the model name will be used.

The only required option for chromable is document:.

At this point, chromable will create, update, and destroy the ChromaDB embeddings for your objects based on Rails after_save and after_destroy callbacks.

To interact with the ChromaDB collection, chromable provides:

• Model.query to query the collection using similar API used in chroma-db gem, except for accepting text: instead of query_embeddings:. Extra arguments will be passed to the embedder: as options. Behind the scenes, Model.query will embed the given text:, then query the collection, and return the closest results: records.
• Model.collection to access the collection directly.
• Model.delete_collection to delete the entire collection.

puts Post.collection.count # Gets the number of documents inside the collection. Should always match Post.count.

Post.query(
  text: params[:query],
  results: 20,
  where: chroma_search_filters,
  is_query: true # `is_query` here will be passed to `Post.embed` as an option.
)

Post.first.neighbors(results: 20) # => [#<Post:0x0000ffff9e0b5f10 id: "0beb0f98...", ...>, ...]

Also, chromable provides the following methods for each model instance:

• embedding: Retrieves the instance's ChromaDB embedding object.
• upsert_embedding: Creates or updates the instance's ChromaDB embedding object.
• destroy_embedding: Destroys the instance's ChromaDB embedding object.
• neighbors: Gets the closest results: records to the current record.

All these methods (including Model.query, Model.collection, and Model.delete_collection) are available with chroma_ prefix, if you have similar methods defined in your model.

After checking out the repo, run bin/setup to install dependencies. Then, run rspec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle install. To release a new version, update the version number in version.rb, and then create a git tag for the version, push git commits and the created tag. The Publish Gem Github Action will push the .gem file to rubygems.org.

Bug reports and pull requests are welcome on GitHub at https://github.com/AliOsm/chromable. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the code of conduct.

The gem is available as open source under the terms of the MIT License.

Everyone interacting in the Chromable project's codebases, issue trackers, chat rooms and mailing lists is expected to follow the code of conduct.