Easy8 initialization process

In this article we try to explain the order in which is Easy8 initialized with Zeitwerk enabled

1. Engine Initializers #1
2. code in lib/EngineName/engine.rb, e.g. lib/easy_b2b/engine.rb

3. code that is not in any later blocks

4. Rails application initializers

5. config/initializers/*

6. code that is not in any of the later blocks

7. Engines Initializers #2

8. initializer code blocks from lib/EngineName/engine.rb

   class Engine < ::Rails::Engine
     initializer 'My initializer' do
       # Custom initializer
     end
   end
   

9. Engines Initializers #3

10. config/initializers/*

11. Rails.application.config.to_prepare blocks

12. These are run on every code reload in development mode

13. This block runs before patches are applied !!

14. Railtie.config.to_prepare blocks

15. These are run on every code reload in development mode

16. Redmine plugins are loaded in this block

    • in Rails.application.config.to_prepare
    • this means that EasyB2b::Engine.config.to_prepare will be called after plugin application if defined in easy_b2b/config/initializers
    • if defined in easy_b2b/lib/easy_b2b/engine.rb then it will run before patches

17. Rails.application.config.after_initialize blocks

Example

1.

# Rys/lib/EngineName/engine.rb
class Rys < ::Rails::Engine
  puts "This runs right away"
end

2.

# Rails.root/config/initializers/30-redmine.rb
puts "This is where plugins/PLUGIN_NAME/app/* + lib is added to autoload_paths"

3.

# Rys/lib/EngineName/engine.rb
class Rys < ::Rails::Engine
  initializer do
    puts "Enqueued but runs very early"
  end
end

4.

# Rys/config/initializers/03_hooks.rb
puts "Enqueued but runs very early"

5.

# Rails.root/config/initializers/00_core_plugins.rb
Rails.application.config.to_prepare do
  puts "This is before easy patch application"
end

6.

# Rys/config/initializers/03_hooks.rb
Rails.application.config.to_prepare do
  puts "This is before easy patch application"
end

7.

# Rys/lib/EngineName/engine.rb
class Rys < ::Rails::Engine
  config.to_prepare do
    puts "This is still before easy patch application"
  end
end

8.

# Rails.root/config/initializers/30_redmine.rb
# inside Redmine::PluginLoader.load
Rails.application.config.to_prepare do
  puts "In this block redmine plugin initializers are run"
end
# Rails.root/config/initializers/33_patches.rb
Rails.application.config.to_prepare do
  puts "In this block we apply easy_patches"
end

9.

# Rys/config/initializers/03_hooks.rb
Rys::Engine.config.to_prepare do
  puts "Runs as #1 out of these 3"
end
Rails.application.config.to_prepare do
  puts "Runs as #2 out of these 3"
end
Rys::Engine.config.to_prepare do
  puts "Runs as #3 out of these 3"
end

10.

# Rys/lib/EngineName/engine.rb
class Rys < ::Rails::Engine
  config.after_initialze do
    puts "This is the first after_initialize block"
  end
end

11.

# Rails.root/config/30-redmine.rb
Rails.application.config.to_prepare do
  puts "After initialize block from core app"
end

12.

# Rys/config/initializers/03_hooks.rb
Rails.application.config.to_prepare do
  puts "After initialize block from engine initializer files"
end