Module: CacheInspector::Subscriber

Defined in:
lib/cache_inspector/subscriber.rb

Constant Summary collapse

EVENTS = 
%w[
  cache_read.active_support
  cache_generate.active_support
  cache_write.active_support
  cache_delete.active_support
  cache_fetch_hit.active_support
].freeze

Class Method Summary collapse

Class Method Details

.handle_event(event, e) ⇒ Object 



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# File 'lib/cache_inspector/subscriber.rb', line 29

def self.handle_event(event, e)
  env = rails_env
  return unless @config.enabled?(env)

  key = e.payload[:key]
  value = e.payload[:value]
  size_kb = value.to_s.bytesize / 1024.0 if value

  msg = "#{@config.log_prefix} #{event} key=#{key}"

  case event
  when "cache_fetch_hit.active_support"
    msg << " (hit)"
  when "cache_generate.active_support"
    msg << " (miss -> generating)"
  when "cache_write.active_support"
    msg << " (write)"
    if size_kb && size_kb > @config.warn_large_size_kb
      msg << " ⚠️ large write: #{size_kb.round(1)}KB"
    end
  end

  if @config.log_payloads && value
    msg << " payload=#{truncate(value.inspect)}"
  end

  logger.info(msg)
end

.install!(config) ⇒ Object 



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# File 'lib/cache_inspector/subscriber.rb', line 14

def self.install!(config)
  return if @installed

  @config = config

  EVENTS.each do |event|
    ActiveSupport::Notifications.subscribe(event) do |*args|
      event_obj = ActiveSupport::Notifications::Event.new(*args)
      handle_event(event, event_obj)
    end
  end

  @installed = true
end

.logger ⇒ Object 



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# File 'lib/cache_inspector/subscriber.rb', line 62

def self.logger
  if defined?(Rails) && Rails.respond_to?(:logger)
    Rails.logger
  else
    @logger ||= Logger.new($stdout)
  end
end

.rails_env ⇒ Object 



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# File 'lib/cache_inspector/subscriber.rb', line 70

def self.rails_env
  if defined?(Rails)
    Rails.env.to_sym
  else
    (ENV["RACK_ENV"] || "development").to_sym
  end
end

.truncate(str, max = 150) ⇒ Object 



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# File 'lib/cache_inspector/subscriber.rb', line 58

def self.truncate(str, max = 150)
  str.length > max ? "#{str[0..max]}..." : str
end