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A simple extensions which allows you to automatically inject dependencies to your object constructors from a configured container.

It does 3 things:

  • Defines a constructor which accepts dependencies
  • Defines attribute readers for dependencies
  • Injects dependencies automatically to the constructor with overridden .new


Add this line to your application's Gemfile:

gem 'dry-auto_inject'

And then execute:

$ bundle

Or install it yourself as:

$ gem install dry-auto_inject


You can use AutoInject with any container that responds to []. In this example we're going to use dry-container:

# set up your container
my_container = Dry::Container.new

my_container.register(:data_store, -> { DataStore.new })
my_container.register(:user_repository, -> { container[:data_store][:users] })
my_container.register(:persist_user, -> { PersistUser.new })

# set up your auto-injection function
AutoInject = Dry::AutoInject(my_container)

# then simply include it in your class providing which dependencies should be
# injected automatically from the configured container
class PersistUser
  include AutoInject[:user_repository]

  def call(user)
    user_repository << user

persist_user = my_container[:persist_user]

persist_user.call(name: 'Jane')


After checking out the repo, run bin/setup to install dependencies. Then, run rake spec 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 exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.


Bug reports and pull requests are welcome on GitHub at https://github.com/dry-rb/dry-auto_inject.