A simple dry-monitor example

dry-monitor-example.rb

require 'dry/monitor/notifications'

module MyApp
  def self.notifications
    @__notifications__ ||= Dry::Monitor::Notifications.new(:my_app)
  end

  notifications.register_event("users.created")

  class Logger
    def on_users_created(user:, object:, time:)
      puts "user #{user} created by #{object} in #{time}ms"
    end
  end

  class CreateUser
    attr_reader :notifications

    def initialize(notifications)
      @notifications = notifications
    end

    def call(user)
      notifications.instrument("users.created", object: self, user: user) do
        # do your thing
        sleep 1
        user
      end
    end
  end
end

# subscribe an object where its methods are treated as event listeners
MyApp.notifications.subscribe(MyApp::Logger.new)

# subscribe arbitrary code as an event listener
MyApp.notifications.subscribe("users.created") do |event|
  puts "EVENT: #{event.id}"
  puts "PAYLOAD: #{event.payload.inspect}"
end

create_user = MyApp::CreateUser.new(MyApp.notifications)
create_user.call(name: "Jane")

output.txt

user {:name=>"Jane"} created by #<MyApp::CreateUser:0x007fa61618d1c0> in 1005.25ms

EVENT: users.created
PAYLOAD: {:object=>#<MyApp::CreateUser:0x007fa61618d1c0 @notifications=#<Dry::Monitor::Notifications:0x007fa6158651d8 @id=:my_app, @clock=#<Dry::Monitor::Clock:0x007fa6158779a0>, @__bus__=#<Dry::Events::Bus:0x007fa61585ea40 @listeners=#<Concurrent::Map:0x007fa61585f3f0 entries=1 default_proc=#<Proc:0x007fa61606bb98@/Users/solnic/Workspace/dry-rb/dry-events/lib/dry/events/constants.rb:8>>, @events=#<Concurrent::Map:0x007fa61585ff80 entries=1 default_proc=nil>>>>, :user=>{:name=>"Jane"}, :time=>1005.25}