Active_model_serializers: Couldn't find template for digesting

[chrishough]

Started GET "/api/shops/1" for 71.237.193.222 at 2016-06-21 15:44:34 -0700
Processing by Api::ShopsController#show as HTML
  Parameters: {"id"=>"1"}
  Shop Load (0.6ms)  SELECT  `shops`.* FROM `shops` WHERE `shops`.`id` = 1 LIMIT 1
  Couldn't find template for digesting: shops/show
[active_model_serializers] Cache read: shops/1-20160621220542000000000/attributes ({:expires_in=>1 day, :skip_digest=>true})
[active_model_serializers] Cache fetch_hit: shops/1-20160621220542000000000/attributes ({:expires_in=>1 day, :skip_digest=>true})
[active_model_serializers]   User Load (0.4ms)  SELECT  `users`.* FROM `users` WHERE `users`.`id` = 1 LIMIT 1
[active_model_serializers]   Provider Load (0.4ms)  SELECT  `providers`.* FROM `providers` WHERE `providers`.`id` = 5 LIMIT 1
[active_model_serializers] Rendered ShopsShowSerializer with ActiveModelSerializers::Adapter::Attributes (193.61ms)
Completed 200 OK in 470ms (Views: 186.7ms | ActiveRecord: 64.1ms)

I have been researching this for awhile now. With GET requests to my JSON api I am seeing these in the logs. Any ideas?

[bf4]

How are you calling render? Are you using the cache-digest gem or anything? This isn't coming from AMS

[bf4]

e.g. https://github.com/rails/rails/issues/19198

[chrishough]

No, I am not. I am just using this for example:

  def show
    respond_with @shop, serializer: ShopsShowSerializer if stale?(@shop)
  end

and...

class ShopsSerializer < ActiveModel::Serializer
  cache expires_in: 1.day, skip_digest: true
  attributes :id
end

[bf4]

@chrishough it's mentioned in http://www.akitaonrails.com/2016/03/23/improving-your-microservices-integration-performance-with-memcache-and-etags seems to be a result of if stale?(@shop) that is okay

[bf4]

@chrishough would you consider this resolved, that it's a non-Rails, non-AMS warning that can be ignored?

[remear]

Closing due to lack of submitter response.

[chrishough]

Sorry for the delay, I have a list of these issues I need to get back to. The issue has disappeared magically for now. I would consider this closed and will re-post if it pops back up.

[bf4]

Great!

[another-dave]

This isn't an AMS issue (at least for me), but just adding details here because this is the best search hit for the error.

I was getting this for an API-only JSON endpoint:

class FooController < ApplicationController
    def bar
        if stale?(bar)
            respond_to do |format|
                format.json do
                    render json: bar
                end
            end
        end
    end
end

Was processing OK, but giving me an error in the logs:

Couldn't find template for digesting: foo/bar

I noticed that the docs for stale? say:

:template By default, the template digest for the current controller/action is included in ETags. If the action renders a different template, you can include its digest instead. If the action doesn't render a template at all, you can pass template: false to skip any attempt to check for a template digest.

So I updated my stale? check to:

if stale(etag: bar, last_modified: bar.updated_at, template: false)

And it no longer logs the error