discourse-chat-integration/app/models/plugin_model.rb

class DiscourseChat::PluginModel < PluginStoreRow
  PLUGIN_NAME = 'discourse-chat-integration'

  default_scope { self.default_scope }

  after_initialize :init_plugin_model
  before_save :set_key

  def self.default_scope
    where(type_name: 'JSON')
      .where(plugin_name: self::PLUGIN_NAME)
      .where("key LIKE ?", "#{self.key_prefix}%")
  end

  def self.key_prefix
    raise 'Not implemented'
  end

  private

  def set_key
    self.key ||= self.class.alloc_key
  end

  def init_plugin_model
    self.type_name ||= 'JSON'
    self.plugin_name ||= PLUGIN_NAME
  end

  def self.alloc_key
    DistributedMutex.synchronize("#{self::PLUGIN_NAME}_#{self.key_prefix}_id") do
      max_id = PluginStore.get(self::PLUGIN_NAME, "#{self.key_prefix}_id")
      max_id = 1 unless max_id
      PluginStore.set(self::PLUGIN_NAME, "#{self.key_prefix}_id", max_id + 1)
      "#{self.key_prefix}#{max_id}"
    end
  end

end