Make dymanic session store key for Rails on Multi-Tenant Arch

dynamic_cookie_store.rb

class ActionDispatch::Session::DynamicCookieStore
  def initialize(app, options = {})
    @app = app
    @options = options
  end

  def call(env)
    # Write a middleware to resolve tenant service(each service bind one doman) based on request.host
    service = env['tenant.service']

    new_options = @options.dup

    if service
      new_options[:key] = service_to_key(service)
      new_options[:domain] = service.domain
      new_options[:same_site] = service.cookie_same_site
    else
      new_options[:domain] = nil
      new_options[:same_site] = nil
    end

    ActionDispatch::Session::CookieStore.new(@app, new_options).call(env)
  end

  private

    def service_to_key(service)
      "#{service.class.name.underscore}_#{service.id}"
    end
end

session_store.rb

# Why I need this?
# 
# Rails cookie session store is a static value set on boot, in config/initializers/session_store.rb
# My Rails project is multi-tenant arch, she allows tenant bind their own domains to each service(Workspace, 
# CMS, Community, Wiki etc.), some domains are in the same zone, such as:
# 
# - www.helo.com
# - app.hello.com
# - help.app.hello.com
# 
# if three domains above are binded by our system, their cookies are messed up due to the same name 'baklib',
# this cause some weird cases we found.
# 
# Thinking:
# 
# If we can make each tenant service has their own cookie name, it should be fixed.
# 
# How:
# 
# Write a middleware.
# 

# before
Rails.application.config.session_store :cookie_store, key: 'baklib', httponly: true

# after
Rails.application.config.session_store :dynamic_cookie_store, key: 'baklib', httponly: true