# dry auto inject initialization without inheritance

**URL:** <https://discourse.dry-rb.org/t/dry-auto-inject-initialization-without-inheritance/1492>\
**Category:** Support\
**Created:** [July 27, 2022, 10:12pm UTC](https://discourse.dry-rb.org/t/dry-auto-inject-initialization-without-inheritance/1492 "2022-07-27T22:12:09Z")\
**Posts on this page:** 4\
**Page:** 1

<div class="post-metadata">

**Author:** ![jedschneider](https://yyz1.discourse-cdn.com/flex031/user_avatar/discourse.dry-rb.org/jedschneider/32/617_2.png) [@jedschneider](https://discourse.dry-rb.org/u/jedschneider)\
**Post date:** [July 27, 2022, 10:12pm UTC](https://discourse.dry-rb.org/t/dry-auto-inject-initialization-without-inheritance/1492/1 "2022-07-27T22:12:09Z")

</div>

Hi Folks, i ran into something today with the Injector that I didn’t have a good solve for right away, so I thought I’d ask. Scenario: we need to initialize a class with a unique property that changes based on context.

All examples are using Ruby 2.7.

```ruby
class Container
  register :client do
    Service::Client.new
  end
end

Import = Dry::AutoInject(Container)

class Action
  include import[:client]

  def call(data)
    # the action instance needs to pass on some specific config
    # known by the context of the caller
    client.call(config, data)
  end
end

```

Our current container uses the default kwyd arguments injection strategy, but I couldn’t seem to get around ruby syntax violations. For example:

```ruby
class Client
end

class Container
  extend Dry::Container::Mixin
  register(:client) do
    Client.new
  end
end

Import = Dry::AutoInject(Container)

class Action
  include Import[:client]

  def initialize(config:); end
end

action = Action.new(config: {})

```

raises:

```auto
in `initialize': unknown keyword: :client (ArgumentError)

```

and since `Action` does not inherit, I can’t use the keyword in the subclass, filter it out, and pass it up with `super` (which I’ve done in subclass cases historically).

thusfar my two best options are of the variety:

```ruby
class Action
  include Import[:client]

  attr_accessor :config
end

config = {}
action.new.tap { _1.config = config }

```

any other thoughts on initialization strategies?

Thanks in advance!

---

<div class="post-metadata">

**Author:** ![bkuhlmann](https://yyz1.discourse-cdn.com/flex031/user_avatar/discourse.dry-rb.org/bkuhlmann/32/557_2.png) [@bkuhlmann](https://discourse.dry-rb.org/u/bkuhlmann)\
**Post date:** [July 28, 2022, 1:09am UTC](https://discourse.dry-rb.org/t/dry-auto-inject-initialization-without-inheritance/1492/2 "2022-07-28T01:09:30Z")

</div>

Hey Jed. I’m not sure I fully follow what you are trying to do here regarding the `Client` but, from the examples you’ve provided, I think the piece you are missing is ensuring `Action` gets constructed with both your `config` keyword argument _and_ your injected `client` dependency by passing your dependencies to `super`.

I rewrote your code snippets, above, as a runable snippet. Note that I wrote this in Ruby 3.1.x syntax to save on vertical space. Regardless, I think all you’ll need to study is how I setup the `Action` constructor.

Here’s the solution:

```ruby
#! /usr/bin/env ruby
# frozen_string_literal: true

# Save as `snippet`, then `chmod 755 snippet`, and run as `./snippet`.

require "bundler/inline"

gemfile true do
  source "https://rubygems.org"

  gem "amazing_print"
  gem "debug"
  gem "dry-container"
  gem "dry-auto_inject"
end

class Client
  def call(config, data) = ap "I'm the client and I just got: Config: #{config}, Data: #{data}."
end

class Container
  extend Dry::Container::Mixin

  register(:client) { Client.new }
end

Import = Dry::AutoInject Container

class Action
  include Import[:client]

  def initialize config:, **dependencies # Important, so AutoInject and still provide client as a keyword.
    super(**dependencies)
    @config = config
  end

  def call(data) = client.call config, data

  private

  attr_reader :config
end

Action.new(config: {a: 1}).call "test_data"

```

Running the above will output as:

```auto
Fetching gem metadata from https://rubygems.org/...
Resolving dependencies...
"I'm the client and I just got: Config: {:a=>1}, Data: test_data."

```

Does the above fix your issue?

---

<div class="post-metadata">

**Author:** ![jedschneider](https://yyz1.discourse-cdn.com/flex031/user_avatar/discourse.dry-rb.org/jedschneider/32/617_2.png) [@jedschneider](https://discourse.dry-rb.org/u/jedschneider)\
**Post date:** [July 28, 2022, 2:28am UTC](https://discourse.dry-rb.org/t/dry-auto-inject-initialization-without-inheritance/1492/3 "2022-07-28T02:28:27Z")

</div>

@bkuhlmann Yes, I think this will solve the issue! My mistake was not destructuring the arguments in the init. Thanks for the quick reply! Jed

---

<div class="post-metadata">

**Author:** ![jedschneider](https://yyz1.discourse-cdn.com/flex031/user_avatar/discourse.dry-rb.org/jedschneider/32/617_2.png) [@jedschneider](https://discourse.dry-rb.org/u/jedschneider)\
**Post date:** [July 30, 2022, 3:01pm UTC](https://discourse.dry-rb.org/t/dry-auto-inject-initialization-without-inheritance/1492/4 "2022-07-30T15:01:36Z")

</div>

Just an update here, we were able to refactor our code to use this solution and it works “as advertised”. Thanks for the help!