Calling cached cell writes nothing to log file about cells HOT 9 CLOSED

We once had this in earlier versions but removed it as nobody seemed to take advantage of this feature. I'd be happy to see a patch, however, maybe we should introduce some cell/debugging.rb module responsible for mixing in development-specific behaviour into cells (e.g. caching logging, template finding output, etc). If you send a patch for logging I can take care of the rest. Thanks!

from cells.

Assuming we only need to support Rails 3 we can use ActiveSupport::Notifications (RailsCast).

I had a quick play with it and simply modifying #expire_cache_key and #render_state in Cell::Caching::ClassMethods to include instrumentation seems to do the job:

def expire_cache_key(key, *args)
  ActiveSupport::Notifications.instrument("expire_fragment.action_controller", :key => key) do
    cache_store.delete(key, *args)
  end
end

def render_state(state, *args)
  return super(state, *args) unless self.class.cache?(state)

  key     = self.class.state_cache_key(state, call_state_versioner(state, *args))
  options = self.class.cache_options[state]

  ActiveSupport::Notifications.instrument("read_fragment.action_controller", :key => key) do
    self.class.cache_store.fetch(key, options) do
      ActiveSupport::Notifications.instrument("write_fragment.action_controller", :key => key) do
        super(state, *args)
      end
    end
  end
end

Note that the instrumentation in #render_state does result in both a read and write being logged the when the cache is empty, so the logic may want to be changed to conditionally do a cache read or write instead of a fetch.

I wasn't sure how to go about testing this however as I couldn't see any caching tests.

from cells.

Yeah, notifications seem to be a good choice, although I'd like to push stuff like this in a Cell::Debugging module. Cash tests are here: https://github.com/apotonick/cells/blob/master/test/rails/caching_test.rb

from cells.

Hi!

Is the Cell::Debugging module feature going forward? We'd be also interested in having such a logging feature. We just started playing caching our cells and its difficult to understand what is happening without some logging.

Regards!

from cells.

Cool, only 3 years later this got implemented. Thanks @Fractious I basically copied your code to Caching::Notifications.

from cells.

Do i need to wire the notifications to the log output myself? As the cache output is pretty usefull for a dev.

... yes i finally made it to try cells

from cells.

@schorsch Yo! Good to see you here!

@timoschilling Hilft!

from cells.

@schorsch
Here is a subscribe example for read_fragment.action_controller and write_fragment.action_controller

ActiveSupport::Notifications.subscribe('read_fragment.action_controller') do |name, start, finish, id, payload|
  name    # => String, name of the event (such as 'read_fragment.action_controller' from above)
  start   # => Time, when the instrumented block started execution
  finish  # => Time, when the instrumented block ended execution
  id      # => String, unique ID for this notification
  payload # => Hash, the payload
  Rails.logger.debug "..."
end

from cells.

@schorsch contact me if you need more support

from cells.