Build a Custom Trigger

Create a Hello World Agent with Time Interval Trigger

Let’s make a simple time interval trigger for a hello world sublayer agent

# bash
mkdir hello_world_agent
cd hello_world_agent
touch Gemfile
touch hello_world_agent.rb
touch time_interval.rb

# Gemfile
source 'https://rubygems.org'
gem 'sublayer', '~>0.1.0'

# bash
bundle install

• Build a sublayer generator with the following description:
  • “A Time Interval Trigger that takes an integer for seconds to wait”

• Paste the result from above into time_interval.rb (rename and adjust arguments if needed)

• Write the following code in hello_world_agent.rb:

  # hello_world_agent.rb
  require "sublayer"
  require "./time_interval.rb"
  
  class HelloWorldAgent < Sublayer::Agents::Base
    trigger TimeInterval.new(2)
  
    goal_condition { false }
  
    check_status {}
  
    step do
      puts "hello world"
    end
  end
  
  HelloWorldAgent.new.run
  

  Adjust the name of the TimeInterval class and the arguments as needed!

• Run your code:

  ruby hello_world_agent.rb
  

Additional Examples of Custom Triggers

File Change Trigger Example

Create a custom trigger that activates when a specific file is changed.

class FileChangeTrigger < Sublayer::Triggers::Base
  def initialize(file_path)
    @file_path = file_path
  end

  def setup(agent)
    Listen.to(File.dirname(@file_path)) do |modified, added, removed|
      if modified.include?(@file_path)
        activate(agent)
      end
    end.start
  end
end

class MyFileChangeAgent < Sublayer::Agents::Base
  trigger FileChangeTrigger.new("/path/to/watched_file.txt")

  goal_condition { false }

  check_status {}

  step do
    puts "File changed!"
  end
end

HTTP Endpoint Trigger Example

Create a trigger that starts an agent based on an HTTP request.

require 'sinatra'
class HTTPEndpointTrigger < Sublayer::Triggers::Base
  def initialize(endpoint:, port:)
    @endpoint = endpoint
    @port = port
  end

  def setup(agent)
    Sinatra::Base.set :port, @port
    Sinatra::Base.set :bind, '0.0.0.0'

    Sinatra::Base.post(@endpoint) do
      activate(agent)
      status 204 # No content
    end

    Thread.new do
      begin
        Sinatra::Base.run!
      rescue StandardError => e
        puts "Error starting HTTP endpoint: #{e.message}"
      end
    end
  end
end

class MyHTTPAgent < Sublayer::Agents::Base
  trigger HTTPEndpointTrigger.new(endpoint: "/trigger", port: 4567)

  goal_condition { false }

  check_status {}

  step do
    puts "HTTP endpoint triggered!"
  end
end

Run this agent and send a GET request to http://localhost:4567/trigger to activate it.