Outputs

Outputs are the results of a service.

TL;DR

Define outputs using the output keyword in the service class
Outputs can have default values
Outputs can be validated by type In Development

Define Outputs

You define outputs using the output keyword in the service class.

class AI::Chat < ApplicationService
  output :messages
  output :cost
end

Write Outputs

Outputs function similarly to instance variables created with attr_accessor.

class AI::Chat < ApplicationService
  # Steps
  step :chat

  # Outputs
  output :messages
  output :cost

  private

  def chat
    self.messages = ["Hello!", "Hi, how are you?"]
    self.cost = 0.0013
  end
end

To set outputs programmatically, use the outputs.set method or hash syntax.

class AI::Chat < ApplicationService
  # ...

  def chat
    outputs.set(:messages, ["Hello!", "Hi, how are you?"])
    outputs.set(:cost, 0.0013)

    # Or use hash syntax

    outputs[:messages] = ["Hello!", "Hi, how are you?"]
    outputs[:cost] = 0.0013
  end
end

Type Validation

In Development

You can specify the type of output using the type option. The output type will be validated when the service successfully completes.

class AI::Chat < ApplicationService
  output :messages, type: :string, array: true
  output :cost, type: :float
end

Default Values

Set default values for outputs using the default option. The default value will be automatically set before the execution of steps.

class AI::Chat < ApplicationService
  output :cost, default: 0.0
end

What's Next?

Next, learn about context.