Squashed commit of the following:

commit 65a7a5c009a13005273653812ffbf460cb28159b
Merge: 4d8b7c0 e0fe05d
Author: Nate Berkopec <nate.berkopec@gmail.com>
Date:   Sun Feb 19 17:49:42 2023 -0800

    Merge branch 'on_booted_feature' of github.com:rodzyn/puma into rodzyn-on_booted_feature

commit e0fe05d
Author: Marcin Olichwirowicz <marcin.olichwirowicz.ext@qonto.com>
Date:   Sat Jan 28 20:09:42 2023 +0800

    Add on_booted support for Rack::Handler::Puma

commit 2a14a32
Author: Marcin Olichwirowicz <marcin.olichwirowicz@nedap.com>
Date:   Wed Sep 22 16:10:23 2021 +0200

    Add on_booted event

README.md

@@ -157,6 +157,15 @@ before_fork do
 end
 ```
 
+You can also specify a block to be run after puma is booted using `on_booted`:
+
+```ruby
+# config/puma.rb
+on_booted do
+  # configuration here
+end
+```
+
 ### Error handling
 
 If puma encounters an error outside of the context of your application, it will respond with a 500 and a simple

lib/puma/cli.rb

@@ -93,7 +93,7 @@ def configure_control_url(command_line_arg)
     #
 
     def setup_options
-      @conf = Configuration.new do |user_config, file_config|
+      @conf = Configuration.new({}, {events: @events}) do |user_config, file_config|
         @parser = OptionParser.new do |o|
           o.on "-b", "--bind URI", "URI to bind to (tcp://, unix://, ssl://)" do |arg|
             user_config.bind arg

lib/puma/dsl.rb

@@ -664,6 +664,16 @@ def after_worker_fork(&block)
 
     alias_method :after_worker_boot, :after_worker_fork
 
+    # Code to run after puma is booted (works for both: single and clustered)
+    #
+    # @example
+    #   on_booted do
+    #     puts 'After booting...'
+    #   end
+    def on_booted(&block)
+      @config.options[:events].on_booted(&block)
+    end
+
     # When `fork_worker` is enabled, code to run in Worker 0
     # before all other workers are re-forked from this process,
     # after the server has temporarily stopped serving requests

lib/rack/handler/puma.rb

@@ -27,7 +27,7 @@ def config(app, options = {})
         end
       end
 
-      conf = ::Puma::Configuration.new(options, default_options) do |user_config, file_config, default_config|
+      conf = ::Puma::Configuration.new(options, default_options.merge({events: @events})) do |user_config, file_config, default_config|
         if options.delete(:Verbose)
           require 'rack/common_logger'
           app = Rack::CommonLogger.new(app, STDOUT)
@@ -63,8 +63,8 @@ def run(app, **options)
 
       log_writer = options.delete(:Silent) ? ::Puma::LogWriter.strings : ::Puma::LogWriter.stdio
 
-      launcher = ::Puma::Launcher.new(conf, :log_writer => log_writer)
-
+      launcher = ::Puma::Launcher.new(conf, :log_writer => log_writer, events: @events)
+      
       yield launcher if block_given?
       begin
         launcher.run

test/config/event_on_booted.rb

@@ -0,0 +1,3 @@
+on_booted do
+  puts "on_booted called"
+end

test/config/event_on_booted_exit.rb

@@ -0,0 +1,5 @@
+on_booted do
+  pid = Process.pid
+  Process.kill :TERM, pid
+  Process.wait pid
+end

test/test_integration_cluster.rb

@@ -130,6 +130,16 @@ def test_term_suppress
     assert_equal 0, status
   end
 
+  def test_on_booted
+    cli_server "-w #{workers} -C test/config/event_on_booted.rb -C test/config/event_on_booted_exit.rb test/rackup/hello.ru", no_wait: true
+
+    output = []
+
+    output << $_ while @server.gets
+
+    assert output.any? { |msg| msg == "on_booted called\n" } != nil
+  end
+
   def test_term_worker_clean_exit
     cli_server "-w #{workers} test/rackup/hello.ru"
 

test/test_integration_single.rb

@@ -49,6 +49,16 @@ def test_term_exit_code
     assert_equal 15, status
   end
 
+  def test_on_booted
+    cli_server "-C test/config/event_on_booted.rb -C test/config/event_on_booted_exit.rb test/rackup/hello.ru", no_wait: true
+
+    output = []
+
+    output << $_ while @server.gets
+
+    assert output.any? { |msg| msg == "on_booted called\n" } != nil
+  end
+
   def test_term_suppress
     skip_unless_signal_exist? :TERM
 

test/test_rack_handler.rb

@@ -4,6 +4,48 @@
 # RackUp#test_bin runs Puma using the rackup bin file
 module TestRackUp
   require "rack/handler/puma"
+  require "puma/events"
+
+  class TestHandlerGetStrSym < Minitest::Test
+    def test_handler
+      handler = Rack::Handler.get(:puma)
+      assert_equal Rack::Handler::Puma, handler
+      handler = Rack::Handler.get('Puma')
+      assert_equal Rack::Handler::Puma, handler
+    end
+  end
+
+  class TestOnBootedHandler < Minitest::Test
+    def app
+      Proc.new {|env| @input = env; [200, {}, ["hello world"]]}
+    end
+
+    def test_on_booted
+      on_booted = false
+      events = Puma::Events.new
+      events.on_booted do
+        on_booted = true
+      end
+
+      launcher = nil
+      thread = Thread.new do
+        Rack::Handler::Puma.run(app, events: events, Silent: true) do |l|
+          launcher = l
+        end
+      end
+
+      # Wait for launcher to boot
+      Timeout.timeout(10) do
+        sleep 0.5 until launcher
+      end
+      sleep 1.5 unless Puma::IS_MRI
+
+      launcher.stop
+      thread.join
+
+      assert_equal on_booted, true
+    end
+  end
 
   class TestPathHandler < Minitest::Test
     def app